UNIT I - PRINCIPLES AND PRACTICES OF MAINTENANCE PLANNING

1. Define maintenance?
Maintenance is the routine and recurring process of keeping a particular machine or asset in
its normal operating conditions So that it can deliver the expected performance or service
without any loss or damage.

2. Define reliability?
Reliability is defined as the probability that a component /system, when operating under
given condition, will perform its intended functions adequately for a specified period of time.
It refers to the like hood that equipment will not fail during its operation.

3. State the benefits of reliability analysis in industries?

The main advantages of imposing reliability requirements are increased productivity and
reductions in forced outage equipment due to planned maintenance activity.

4. Define failure rate?

Failure rate is the ratio of the number of failures during particular unit interval to the average
population during that interval. This failure rate is also known as hazard rate and
instantaneous failure rate.

5. What is Mean Failure Rate?

The mean failure rate h is obtained by finding the mean of the failures rates for specified
period of time.
h = (Z1 + Z2 + Z3+....+Zt) /T
where Zt represents failure rates over the specified period of time T

6. Define Mean Time to Failure.

Let t1 is the time to failure for the first specimen, t2 is the time to failure for the second
specimen and t N is the time to failure for the Nth specimen. Hence the mean time to failure
for N specimens are
MTTR = (t1+t2+......+t N) /N

7. What is Mean Time between Failures (MTBF)?

Mean Time between Failures (MTBF) is the mean or average time between successive
failures of a product. Mean time between failures refers tom the average time of breakdown
until the device is beyond repair.

8. Define Mean Time to Repair (MTTR)?

Mean Time to Repair is the arithmetic mean of the time required to perform maintenance
action. MTTR is defined as the Ratio of total maintenance time and number of maintenance
action.
MTTR = Total maintenance time/ Number of maintenance action.

9. Define Maintenance Action Rate?

Maintenance action rate is the number of maintenance action that can be carried out on
equipment per hour.
10. Define Failure Density?
Failure Density is the ratio of the number of failures during a given unit interval of time to the
total number of items at the very beginning of the test.

11. State the types of reliability?

Reliability can be generally of two types:
Inherent Reliability: It is associated with the quality of the material and design of machine
parts. (ii) Achievable Reliability: It depends upon other factors such as maintenance and
operation of the equipment.
12. Draw the equipment life cycle and name the various phases ln it?
Phase I - Failure pattern inherent in a new product because of manufacturing or design
defects.
Phase II - Life period of an equipment.
Phase III - Failures due to wear out conditions because to aging of the equipment.

13. Define maintainability?

Maintainability is defined as the probability that a unit or system will be restored to specified
working conditions within a given period when maintenance action is taken in accordance
with the prescribed procedures and resources

14. Define availability?

Availability is the ratio of the time at which equipment is available for the designated
operation/service to the total time of operation and maintenance of the equipment. It is also
defined as the ratio of equipment uptime to the equipment uptime and downtime over a
specified period of time.

15. State the advantages of life cycle cost analysis.

(i) Integration of engineering, economics and financial aspects lead to the way of robust
metric for the selection and purchase equipment required for the industry.
(ii) Reduced operating and maintenance cost of equipment due to cost analysis over span of
time.
(iii) It leads to the selection of proper and economically viable equipment.

16. Draw the curve to determine the economic life of equipment?

The economic life of equipment depends on the maintenance and repair costs, availability and
operational efficiency. A plot of cumulative efficiency and maintenance and repair cost per
cumulative hours Vs operating hours of the equipment to find the economic life of the
equipment.

17. State the components of maintenance cost?

The maintenance cost is comprised of two factors:
(i) Fixed cost: This includes the cost of support facilities including the maintenance staff.
(ii) Variable cost: This includes the consumption of spare parts, replacement of
components and cost other facilities requirements of maintenance.

18. State the role of maintenance budget

The maintenance budget is used to set aside certain amount of money to meet the
expenditures incurred in achieving the objectives of maintenance.

19. State the types of maintenance budget?

(i) Appropriation Budget: Budget used to allocate money for each activity independently.
(ii) Fixed Budget: Fixed used to allocate money for a specified period of time. (iii)Variable
Budget: Dynamic allocation of expenditure based on maintenance requirements and
activities.

20. State the any two objectives of Maintenance planning

To achieve minimum breakdown
To keep the plant in working condition at the lowest possible cost
To ensure the availability of the machines and services in an optimum working condition

21. What are the basic principles of Maintenance planning?

Maintenance planning is the task of organizing resources to carry out job satisfactorily at
reasonable cost within specified period of time. Maintenance planning involves
assignment of job to the maintenance crew.
 22. What are the benefits of sound management system?
Minimization of downtime.
Improvement in availability of system.
Extended life of equipment.
Safety and smooth operation of the process
Provide adequate back up supply

23. What are the objectives of maintenance?

To achieve product quality and customer satisfaction through adjusted & serviced equipment
Maximize useful life of equipment
Keep equipment safe and prevent safety hazards
Minimize frequency and severity of interruptions
Maximize production capacity – through high utilization of facility

24. Define the MWT.

MWT refers mean wait time. It is defined average length of time a customer waits before
being served.

Part B
1. State the various objectives of Maintenance planning.
The most important objective of the maintenance system is the maximization of availability
of equipments and facilities so as to help in achieving goals of the organization.

The following are objectives of planned maintenance activities

 To achieve minimum breakdown
 To keep the plant in working condition at the lowest possible cost
 To ensure the availability of the machines and services in an optimum working condition
 To keep the machines and other facilities in a condition to be used to achieve the maximum
profit without any interruption or hindrance
 To keep the time schedule of delivery to the customers or to the sections for further
processing
 To meet the availability requirements for critical equipments
 To keep the maintenance cost as low as possible for non critical equipments
 To control cost of maintenance related activities
 To provide effective and trained supervision
 To meet the quality requirements of the product
 To increase the profits of production systems

2. Write at least ten maintenance system importance and benefits.

 Minimization of downtime.
 Improvement in availability of system.
 Extended life of equipment.
 Safety and smooth operation of the process
 Provide adequate back up supply
 Minimization of normal expected wear and tear of equipment.
 Safety of the personal involved in the organization.
 Increased reliability of the system.
 Provide proper working environment.

3. Explain the principles of maintenance?

The principles of maintenance are
 to guide the staff to work efficiently
 to achieve overall objectives of maintenance system
The main areas of work governed by these principles are
a) Plant management in maintenance work:
The main role of a maintenance function is
 To provide safe and effective operation of the equipment
 To achieve the desired targets on time with economics usage of resources.
b) Production and maintenance objectives:
 The plant operation is driven by the production targets.
 The objective of maintenance function is to support these target.
 The achievement of desired goals of the production system is to be supported by both the
production and maintenance department to ensure smooth and successful operation of the
industry.
c) Establishment of work order and recording system:
 The maintenance system should have proper work and recording system.
 The work order for the maintenance function indicates the nature of work to be performed
and the series of operations to be followed to execute a particular job.
 It is necessary to maintain proper records and entries to monitor the maintenance function.
d) Information based decision making:
 The maintenance objectives are successfully achieved by the use of reliable information
system.
 Reliable information is used to meet the manpower and spare parts requirements of the
industry.
e) Adherence to planned maintenance strategy:
 A sound maintenance management should adhere to the planned maintenance strategy.
 It includes the use of manufacturer information on the life and maintenance schedules of
the equipment and other material resources available.
f) Planning of maintenance function:
All the maintenance function are to be carefully executed by a way of proper planning to
ensure the effective utilization of manpower and materials.
g) Manpower for maintenance:
 The manpower requirement of the maintenance system must be carefully evaluated
based on the time and motion study.
 The requirements should also satisfies the need arising in case of overhauls,
component replacement, emergency and unscheduled repair.
h) Work force control:
 Determination of exact work force required to meet the maintenance objectives of the
system is difficult task due to the element of uncertainty.
 Hence the proper control and monitoring of workforce are needs to be ensured.
i) Role of spare parts :
Availability of spare parts ensures proper function of the maintenance work.
j) Training of maintenance work force:
 Training of the workforce must be integral part of any good maintenance management
system.
 Training helps the workforce to learn about the modern techniques, recent trends in
maintenance and to chalk out a strategy to meet the growing demands of the industry

4. Explain the important factors considered in maintenance planning?

The important factors considered in maintenance planning
 Job distribution
 Program
 Manpower allocation
 Staffing
 Planning technique
 Planning procedure
 Estimation of maintenance work
 Maintenance control
a) Job distribution:
The first and foremost task in maintenance planning is the distribution of the jobs to the
personnel for preventive and emergency maintenance works. It is the practice to form two separate
task groups to tackle the both. If not possible a same group can also be used to tackle both the
situations in such way that during scheduling, time must be devoted for unforeseen breakdowns or
situations in maintenance. The distribution is also ensure that neither underutilization nor over
utilization of resource is done
b) Program:
The objective of any planned maintenance system is to reduce the system cost for providing
services.
A maintenance program is well formulated combination of the availability skills and
resources that ensures optimum and appropriate utilization to meet the objectives of organization
The development of maintenance programs involves
 Selection of activities for maintenance
 Determination of the frequency of preventive maintenance
 Decision on the cost effective methodology
i) Selection of activities
The selection of activities is determined by the nature of the system and dictated by the cost
incurred for maintenance. This selection is based on cost involved between preventive and
breakdown maintenance. If the cost of preventive maintenance is lower, then it is preferred over the
breakdown maintenance.
ii) Determination of the frequency of maintenance
The frequency for preventing maintenance is determined from the failure data. The time period for
different types of breakdown to occur is calculated by analyzing the breakdown failure information
this information is also vital in determining the interval of preventive maintenance strategy.
iii) Decision on the cost effective methodology
The important decision in any maintenance activity is working out a cost effective methodology. The
choice is usually taken with either is possible, the defective parts may be replaced during the
scheduled inspections. The decision on scheduled replacement policy has to be based on the analysis
of the past failure data on these components of the system.
c) Manpower allocation:
The manpower allocation is the most important task of the maintenance management group.
It provides adequate manpower to execute various jobs in the system. This should also take into
consideration the skill level of personal deputed for the maintenance tasks. The central idea of
manpower allocation can be drafted using the information available from maintenance records and
planning the task to meet the objectives of the organization. The allocation can only be established
after proper planning and control over maintenance and by keeping reliable records of analysis of
results of maintenance
d) Staffing:
Staffing is the task of providing the required manpower for the maintenance function. This
has to be achieved at optimum cost. Staffing is depend upon the ability of the organization to tackle
the regular as well as attending the unforeseen situations. Staffing should be sufficient to handle
preventive and emergency maintenance task. The advantage of preventive maintenance is that the
work can be planed and scheduled properly for effective resources. Emergence maintenance task are
not predefined and staffing for such case is the difficult due to random nature of failure
e) Planning technique:
Planning techniques are required to develop the overall master plan and for scheduling the major
work of planning and execution. Some of the planning methods are Gantt charts, Milestone method,
Critical path method and Program evaluation review. Evolutionary computation based techniques are
recently used for maintenance planning and scheduling.
f) Planning procedure:
The role of maintenance planning is to evolve a detailed organizational chart for the maintenance
department that include assignment of responsibility and a detailed procedure of feedback and
control mechanism.
Planning procedure involves four step processes
 Organizing maintenance resources to ensure their effective use in future
 Scheduling the resources for the planned period
 Execution of plans according to the schedules
 Establishing a feedback system for all the above processes to know the deficiencies of each
of the processes.
g) Estimation of maintenance work:
Estimation is used to find out the quantity and quality of the maintenance work. This will
help in allocation of the required manpower.
The following methods are used for the estimation of maintenance wok.
 Measurement by estimates,
 Historical data
 By conventional standard time data.
h) Maintenance control:
Maintenance control is the auditing techniques to ensure the effective utilization of the
maintenance budget. This involves the integration of accountability within the system. Proper
accounting of maintenance work should be carried out at every level of the maintenance
organization. This accountability based control improves the quality of man power and material
utilization in an organization.

5. Explain the important and benefits of sound maintenance management system

The profit of any industry depends only on the return of the investment. The capital cost
and operating cost are the major factors involved in any industrial investment. The life of the
equipment and maintenance schedule information provided by manufacturer may not be realized in
practice to make the need for having a sound management system.
The following are the benefits of sound maintenance management system.

 Minimization of downtime.
 Improvement in availability of system.
 Extended life of equipment.
 Safety and smooth operation of the process
 Provide adequate back up supply
 Minimization of normal expected wear and tear of equipment.
 Safety of the personal involved in the organization.
 Increased reliability of the system
 Provide proper working environment.

6. Explain the benefit of availability of reliability information,

The concept of reliability has found increased use in industries engineering maintenance and
management.
Higher reliable equipment ensures uninterrupted availability to achieve the desired
objective of the industry
The main advantage of imposing reliability requirements are increased productivity and
reduction in forced outage equipment due to planned maintenance activity
The application reliability to any equipment helps to identify the flaws in system design,
compare several possible configurations, minimize down time, maximize operational readiness,
reduce operating costs and develop maintenance policies
Need for reliability of Maintenance:
The reliability of a system, equipment and product is very important aspect of quality for its
consistent performance over the expected life span.
 Uninterrupted availability, service and hazard free operation are essential requirements of
large complex industrial system
In case of any sudden failure in any one component, the entire assembly result in loss in
production, may cause potential hazard, accident and interruption in continuity of service.
The reliability helps in planning the scheduled maintenance work to increase the equipment
availability for production. If the overall reliability of any equipment is low, it suggests those
periodic maintenance tasks are required to keep the system at desired level of performance.
Reliability of equipment is of prime importance to maintenance personal, since they have to keep
the equipment in a state of readiness of all time
Reality is defined as the probability that ac component / system, when operating under
given condition will perform it intended functions adequate for a specified period of time. It refers
to the like hood that equipment will not fail during its operation.
The four important factors required in the determination of reliability are
⦁ Reliability expressed as probability
 Adequate performance acquirements
 Duration of adequate performance.
 Environmental or operating conditions.
i) Reliability expressed as probability
Probability is the ratio of the number of times we can expect an event to occur to the
total number of trail undertaken. A reliability factor can be expressed as probability. A reliability
factor equal to one means that device performs satisfactorily for the prescribed duration
under the give environmental condition.

ii) Adequate Performance Requirement:

A system may perform satisfactorily even though one or more components may not be
functioning. In reliability analysis there is a need to define the magnitude of satisfactory or adequate
performance of the system.

iii) Duration of Adequate Performance:

The duration of adequate performance is used to state the time up to which the desired
performance of the system is achieved under the given operating conditions.

iv) Environmental or Operating condition:

Environmental condition indicate the prevailing conditions at which the system is under
operation.

7. Derive an expression of Mean time to failure (MTTF)

Mean time to failure (MTTF)
Let t, is the time to failure for the first specimen, t is the time to failure for the second
specimen and tN is the time to failure for the N specimen. Hence the mean time to failure for N
specimens are
t  t  t  ...  t N
MTTF  1 2 3
N
N
1
  ti
N i 1
It is difficult to record the failure for each component when the numbers of specimens
tested are large.
Instead, we can record the number which fails during the specific intervals of time.
n  2n 2  3n 3  ...  knk
MTTF  1
N

It is better to represent the time as interval instead of time

 Hence time interval  t is instead of one hour
Then MTTF is calculated as
n t  2n 2 t  3n 3t  ...  knk t  ...  rn r t
MTTF  1
N
r
1
  knk t
N k 1

where
n1 is the number of specimen that failed during first hour
n2 is the number of specimen that failed during second hour
nk is the number of specimen that failed during kth hour

8.Explain MTBS, MTBF, MTTF, MTTR , Failure rate, Maintenance action rate and Failure
density
Mean Failure Rate (h)

The mean failure is the rate h is obtained by finding the mean of the failure rates for
specified period of time.
Z  Z 2  Z3  ...  Z n
h 1
T
Mean time to failure (MTTF)
Let t, is the time to failure for the first specimen, t is the time to failure for the
second specimen and t N is the time to failure for the N specimen. Hence the mean time to
failure for N specimens are
t  t  t  ...  t N
MTTF  1 2 3
N
N
1
  ti
N i 1
It is difficult to record the failure for each component when the numbers of specimens
tested are large.
Instead, we can record the number which fails during the specific intervals of time.
n  2n 2  3n 3  ...  knk
MTTF  1
N

It is better to represent the time as interval instead of time.

Hence time interval  t is instead of one hour
Then MTTF is calculated as
n t  2n 2 t  3n 3t  ...  knk t  ...  rn r t
MTTF  1
N
r
1
  knk t
N k 1

where
n1 is the number of specimen that failed during first hour
n2 is the number of specimen that failed during second hour
nk is the number of specimen that failed during kth hour

Mean time between failures (MTBF)

Mean time between failures (MTBF) is the mean or average time between successive
failures of a product. Mean time between failures refers to the average time of breakdown until the
device is beyond repair.
 Mean time to Repair (MTTR)

Mean time to repair (MTTR) is the arithmetic mean of the time required to perform
maintenance action. MTTR is defined as the ratio of total maintenance time and number of
maintenance action.
Total maintenace time
MTTR 
Number of maintenanc e action

Maintenance Action Rate:

Maintenance action rate is the number of maintenance action that can be carried out on
equipment per hour.
1
μ
MTTR

Failure rate
Failure rate is the ratio of the number of failure during particular unit interval to the average
population during that interval. This failure rate is also known as hazard rate and instantaneous
failure rate.

Failure Density
Failure density is the ratio of number of failures during a given interval of time to the total
number of items at the very beginning of the test.

9. What are the different types of organizations are in use in Indian industries?

a) Line organization
Line organization consists of a general foreman and a number of specialist foremen
with their under them.
The specialist foreman executes maintenance work in their respective areas while the general
foreman supervises the total work under his control and coordinates the various maintenance tasks
carried out in the industry. This kind of structure is an old type maintenance organization.

General Foreman

Foreman Foreman
(Mechanical) (Electrical)

\M
Crew Members Crew Members
Line Staff organization
A few more staff members such as storekeeper and clerk are added to the line organization to form
the line organization structure as given below.
General Foreman

Foreman Foreman Store keeper Clerk

(Mechanical) (Electrical)

\M
Crew Members Crew Members

The advantage lies in separating the maintenance work from the storekeeping and the role of
clerk is to record the maintenance activities. The recording of maintenance related activities helps the
organization to restructure the strategies adopted to achieve the objectives of maintenance. The
recording of maintenance related activities helps the organization to restructure the strategies adopted
to achieve the objectives of maintenance.

Maintenance functional organization

Maintenance functional organization is the structure based on craft concept. In this
organization structure, persons joined the organization as apprentices and elevated to higher
positions such as foreman after sufficient experience in their respective jobs.

Maintenance Engineer

Chief Foreman

Foreman Foreman Foreman Foreman

Engine Electrical Shop Welding Shop Hydraulic Shop
Shop
This organization structure is based on craft skills acquired through experience. There is no
\M mechanism available at each stage of organization
formal training

Controlled Maintenance Organization

In Centrally Controlled Maintenance Organization, all major types of maintenance work are
undertaken by the central workshop. The limitation of this kind of maintenance is that it is possible
only for equipment’s which can be shifted to workshop.
 Maintenance Superintendent

Maintenance Engineer

General General General Planning Foreman

Foreman Foreman Foreman Supervisor (Fabrication Shop)
(Mechanical) (Service (Electrical) Shop
Shop)
\M \M
Area Maintenance organization
Area maintenance organization provides better utility of manpower when the units are located
at various locations. For example mining industry, area maintenance manager takes care of
maintenance for a particular area and is equipped with number of workers to carryout maintenance
works including emergency work.

Area Chief Engineer

Area Area Area

Production Administration Maintenance
Engineer Engineer Engineer
Shop

Mechanical
Engineer

Maintenance
Workshop Instumentation Lubrication
Documentation Engineer Engineer
Suprintendent
Engineer
10. Explain the general structure of industrial maintanenance organization

Maintenance

Superintendent
Engineering

Assistant

Facilities Foreman Foreman Foreman Field

Foreman Shop Planning & Engineering Foreman
Maintenance
1. Steam 1. Maintenance 1. Engineering 1. Building
2. Power 2. Repair 1. Work order 2. Design 2. Yard
3. Water 3. Lubrication System 3. Fire
4. Air. 4. Construction 2. Planning & protection
Estimating 4. Waste
3. Scheduling disposal
4. Backlog
control
5. Performance
Report

Organization structure of maintenance department

11. Explain about the external maintenance services

External Maintenance Services
It is available in two forms contract maintenance service and manufacturers
after sale service
Advantages of external maintenance service
⦁ It is very economical
⦁ Technically better and specialist are responsible for maintenance activities
⦁ Skill preservation
⦁ Better service
⦁ Updating to modern and existing trends and needs

Outsourcing in maintenance
The term outsourcing assumed recent importance in the area of computer information
technology and communication due to emergence of Business Process Outsourcing (BPO).
Outsourcing is followed in small industries to hand once the maintenance activities to
external agencies. This is due to the reason that economy of the industry does not permit to have
maintenance people on their own.
Outsourcing is followed in large industries also to ensure maximum control over the
maintenance activities.
⦁ Lost of maintenance is minimized
⦁ No need for having maintenance as a department.
⦁ Better quality of service achieved through employing specialists.
⦁ Better maintenance practice
⦁ Performance metrics are clearly defined & achieved by outsourcing.
12. Explain about maintenance economics
Maintenance Economics
The maintenance budget is sued to set aside crtain amount of money to meet the
expenditures incurred in achieveing the objectives of maintenance.
The following are the types of maintenance budget.
i) Appropriation Budget
Budget used to allocate money for each activity independently
ii) Fixed Budget
Fixed used to allocate money for a specified period of time.
iii) Variable budget
Dynamic allocation of expenditure based on maintenance requirements and
activities.
The maintenance cost is comprised of two factors
Fixed cost
Variable cost
Fixed Cost
This includes the cost of support facilities including the maintenance staff.
Variable Cost
This include the consumption of spare parts, replacement of components and cost
other facilities required to meet the requirements of maintenance.

13. State the factors involved in determining the maintenance cost in an industry
The evaluation of maintenance cost should consider the following factors
 Cost of maintenance from the recorded data.
 Level and requirements of maintenance.
 Cost of replacement of components and assemblies subjected to wearand tear.
 Accounting the number of break downs with their levels
 Downtime of the equipment for wants of maintenance repair.
 Penalty cost due to loss of production.
 Cost of manpower involved.
 Cost of additional manpower requirement for emergency break down and
maintenance.

14. State the step necessary to reduce maintenance cost in an industry

The cost minimization in maintenance can be achieved by following ways
 Centralized, planning, scheduling and control.
 Grouping of specialized workforce.
 Effective labor utilization strategies.
 Proper and effective use of contract maintenance system to reduce the overhead
costs on equipment and manpower.
 Purchase of reliable equipment and spares.
 Use of skilled and trained workforce.
 Proper selection of suitable type of spares, materials and lubricants.
 Proper safety education and formulating the safe practice.
 Constant appraisal and education to workforce about the objectives, strategies and
modern techniques adopted in the area of maintenance.
 Budgetary control and proper check mechanism to implement the cost control
strategies
 UNIT 2 MAINTENANCE CATEGORIES-PREVENTIVE MAINTENTANCE

1. Define the term Preventive Maintenance?

It is a maintenance program which is committed to the elimination or prevention of
corrective and breakdown maintenance. It is designed for day to day maintenance like
cleaning, inspection, lubricating, retightening etc. to retain the healthy condition of
equipments.

2. Define predictive maintenance?

Predictive maintenance is a management technique that uses regular evaluation of
the actual operating conditions of plant equipment, production systems and plant
management function to optimize total plant operation.

3. What is meant by Breakdown maintenance approach?

It is a type of maintenance approach in which equipment is allowed to function /
operate till no failure occurs that no maintenance work is carried out ion advance to prevent
failure.

4. Classify various planned maintenance approach.

 preventive maintenance
 corrective maintenance
 predictive maintenance
 condition based maintenance

5. Define corrective maintenance approach.

Corrective maintenance is the program focused on regular planed tasks that will
maintain all critical machinery and system in optimum operation conditions.

6. What is meant by preventive maintenance approach?

A comprehensive preventive maintenance program involves periodical evaluation of
critical equipment, machinery to detect problem and schedule maintenance task to avoid
degradation in operating conditions. It is designed for day to day maintenance like cleaning
inspection, lubricating, retightening etc. to retain the healthy condition of equipments.

7. List the objectives of corrective maintenance?

 Elimination break downs
 Elimination deviations from optimum operating condition.
 Elimination unnecessary repairs

8. What is meant by predictive Maintenance?

Predictive maintenance is a management technique that uses regular evaluation of the actual
operating conditions of plant equipment production systems and plant management
functions to optimize total plant operation.

9. List out some condition based monitoring techniques and briefly discuss on them.
 Vibration monitoring
 Thermograph
 Tribology
 Electrical motor analysis
10. What is meant by reliability centered maintenance (RCM)?
Reliability centered maintenance is one of the well-established systematic and a step
by step instructional tool for selecting applicable and appropriate maintenance operation
types. It helps in how to analyze all failure modes in a system and define how to prevent or
find those failures early.

11. What is total productive maintenance and discuss its similarities with TQM?
Total productive maintenance is a maintenance program which involves a
newly defined concept of maintaining plants and equipments. The goal ofTPM program is
to significantly increase the production, at the same time increasing employee morale and
job satisfaction.

12. What is meant by reliability centered maintenance?

Reliability centered maintenance is one of the well-established systematic and a step
by step instructional tool for selecting applicable and appropriate maintenance operational
types.

13. What does safety, health and environment pillar of TPM aims at?
 Zero accident,
 Zero health damage
 Zero fires
14. What is limitation of breakdown maintenance?
1. Most repairs are poorly planned due to time constraint caused by production and plant
management. This will cost three to four times than the same repair when it is well planned.
2. This approach focus only on repair or the symptoms of failure and not on the root cause
of failure. This results only in increase in the frequency of repair and correspondingly the
maintenance costs.

15. List the benefits of implementing preventive maintenance.

 It maintains the equipment in good condition to prevent them from bigger problems.
 Prolongs the effective life of the equipments.
 Detects the problem at earlier stages.
 minimizes/eliminates the rework/scrap and helps in reducing the process variability
 Significantly reduces unplanned downtime.
16. Name the five S principles used for implementations of TPM.
 SEIRI – Sort out
 SEITON –Organize
 SEISO – Shine workplace
 SEIKETSU – Standardization
 SHITSUKE – Self discipline
17. List the various pillars of TPM?
 5,S Principle
 Jishu hozen(JH)
 Kaizen
 Planned maintenance
 Quality maintenance.
 Training
 Office TPM
 Safety, health and environment
18. What are the objectives of TPM?
The main objectives of TPM are
 To achieve zero defects
 Achieve zero accidents and zero break downs in all functional areas of an
organization
 To create different team of people to have active participation.
 To aim at minimization of defects and
 To inculcate autonomous policy.

19. Name the various stakeholders of maintenance scheduling.

 Operators
 Planners
 Schedulers
 Maintenance supervisors
 Craftsman
 Store’s in charge
 Operation superintendent

20. Define Maintenance Scheduling.

Maintenance scheduling is a joint maintenance operations activity in which
maintenance agrees to make the recourses available at a specific time when the unit can also
be made available by operations.

21. Define environmental impact

The factor which affects the quality of human environment is called environmental
impact.

22. Mention the reason for preventive maintenance is adopted in the present times.
 It maintains the equipment in good working condition to preventing the m from
bigger problems
 Detects the problem in early stages
 Prolong effective life of equipment
 Minimize the scrap

23. Why do you need lubricants?

 The primary objective of lubrication is to reduce wear and heat between contacting
surfaces in relative motion.
 Lubrication also aids to
⦁ Reduction of rust formation
⦁ Reduce oxidation
⦁ Transmit mechanical power into hydro fluid power systems
⦁ Seal against dust, dirt and water.
 Part B
1. Explain with sketch various types of maintenance approach?

Basically there are two types of maintenance tasks they are

 Unplanned maintenance
 Planned maintenance
Planned maintenance may further be classified into
 Preventive maintenance
 Routine Maintenance
 Corrective maintenance
 Predictive maintenance
 Condition based maintenance
 Reliability centered maintenance

Preventive maintenance
It is a maintenance program which is committed to the elimination or prevention of
corrective and break down maintenance.
Benefits of preventive maintenance
 It maintains the equipment in good condition to preventing them from bigger
problems.
 Prolongs the effective life of the equipments.
 Detects the problem at earlier stages.
 Minimize/eliminates the rework/scrap and helps in reducing the process variability.
 Significantly reduces unplanned downtime
Predictive Maintenance
Predictive maintenance is a management technique that uses regular evaluation of
the actual operating conditions of the plant equipment.

Benefits of preventive maintenance

 Reduced breakdown losses.
 Reduction of quality defects.
 Increased net operating profit
 Reduced maintenance costs

Reliability Centered maintenance

The rough process of RCM is as follows
1. Target products or systems of maintenance should be clearly identified and
necessary data should be collected
2. All possible failures and their effect on target products or systems are systematically
analyzed

Breakdown Maintenance
 In this system the equipment is allowed to function / operate till no failure occurs ie.
no maintenance work is carried out in advance to prevent the failure. As long as
the equipment is functioning at a minimum acceptable level, it is assumed to be
effective. This means the people wait till the equipment fails and repair. This
approach of maintenance is ineffective and extremely expensive. The following
factors contribute to high maintenance costs.
⦁ Poor planning
⦁ Incomplete repair
Limitations:
 Most repairs are poorly planned due to time constraint caused by production and
plant management. This will cost three to four times than the same repair when it is
well planned.
 This approach focus only on repair or the symptoms of failure and not on the root
cause of failure. This results only in increase in the frequency of repair and
correspondingly the maintenance costs.
For example when a bearing fails, it leads to production stop. By this approach
only the bearing will be replaced with a new one, but no attempt will be made to study
the cause of failure or to present a recurrence of this failure. This may seriously affect
the reliability of the system.

Corrective Maintenance
 Corrective maintenance is the progress focused on regular planned tasks that will
maintain all critical machinery and system in optimum operating conditions. The
effectiveness of this program is judged on life cycle cost of critical equipment rather
than on how quickly the broken machines are restored to working conditions. It is
proactive approach towards maintenance management.

The main objectives of this program are to

⦁ Eliminate breakdowns
⦁ Eliminate deviations from optimum operating conditions
⦁ Eliminate unnecessary repair
 ⦁ Optimize all critical plant systems.

Condition based maintenance techniques

Vibration Monitoring
Determines the actual conditions of equipment’s/machines by studying the
noise or vibration produced during functioning.
Thermography
Determines the condition of plant machinery, systems etc. by studying the
emissions of infra-red energy i.e. temperature
Tribology
Determines the dynamic condition of bearing lubrication, rotor support
structure of machinery etc by adopting any one of the techniques like lubricating oil
analysis, spectrographic analysis, ferrography and wear particle analysis.
Electrical Motor Analysis
Determines the problem within motors and other electrical equipment’s.
Visual inspection
Determines the conditions of working elements visually based on the
experience.

2. Explain briefly about TPM with the help of flow chart?

TPM is a maintenance program which involves a newly defined concept of maintaining
plants and equipments.
The goal of TPM program is to significantly increase the production, at the same time
increasing employee morale and job satisfaction.
TPM philosophically resembles TQM in many aspects such as
 Requirements of commitment by top level management
 Requirement of empowering employees to initiate corrective action
 Accepting long range plan on any ongoing process.
Total Productive Maintenance
The goal of TPM program is to significant increase the production, at the same time
increasing employee morale and job satisfaction.
The aim of total production maintenance was to maximize plant and equipment
effectiveness to achieve optimum life cycle cost of equipment. To implement an effective
TPM is an organization there are certain stages to be planned and executed.

Stage I
Announcement by management about TPM. Top level management people should
attend awareness programs on TPM to have proper understanding, commitment and
active involvement. Then all matters about TPM should be communicated to all others
in the company.
⦁ Initial education
⦁ Setting up TPM departmental committees.
⦁ Establishing TPM working system and target
⦁ A plan for institutionalizing.
Implementation of TPM

Stage-I-Initialization

Stage-II-Introduction of TPM

Stage-III-Implementation of
TPM

Stage-IV-Institutionalization

Stage II Introduction Stage

A grand ceremony is to be arranged inviting our customers, affiliated companies,

sister concerns and communicating them that we care for quality.
 Stage III – Implementation Stage
There are certain activities which are performed and known as pillars of TPM are
carried out.

Stage IV Institutionalizing stage

Once the actions are familiar with the TPM process and have experienced success
with small level problems and then with high and complicated problems, the company
can apply for PM award.

The five S principles used for implementations of TPM.

 SEIRI – Sort out

 SEITON –Organize
 SEISO – Shine workplace
 SEIKETSU – Standardization
 SHITSUKE – Self discipline
Various pillars of TPM
 5,S Principle
 Jishu hozen(JH)
 Kaizen
 Planned maintenance
 Quality maintenance
 Training
 office TPM
 Safety, health and environment

3. Discuss in brief the roles of various stakeholders of maintenance scheduling

communication chain.

Maintenance scheduling is a joint maintenance operations activity in which

maintenance agrees to make the recourses available at a specific time when the unit can also
be made available by operations
Various stakeholders of maintenance scheduling.
 Operators
 Planners
 Schedulers
 Maintenance supervisors
 craftsman
 Store’s in charge
 Operation superintendent

Planner:
He/She should ensure that the work is properly planned with respect to customer
requirements, stores material, directly purchased material and special service mentioned on
work order. Also the work to be carried out with the line of safety requirements should be
described.
Craftsman:
He/She executes the assigned task and keep informing the maintenance team, the
outcome as well as any practical difficulty in their part, for any further analysis.
Scheduler:
He/She should ensure that
 Trades are available to conduct the work during the schedule duration
 Materials and/or service availability
 Communicating the details of the above to person involved in maintenance and
operations
Maintenance supervisor:
He/She will be the responsible for the day-to-day activities comprised in weekly
schedule and also determines the business availability. They attend to specify such as to
who-what-where-when.

Storeroom Personnel:
They maintain the records of the receipt of goods and notify if any damages exists.

Operations Superintendent:
He must be kept informed in advance about the equipment condition. Since he is
well aware of production schedule, should determine the opportune time with maintenance
to release the equipment.
Operator:
 He is the person responsible for securing the equipment and report back to the
maintenance personnel if any deviation is observed.

4.Explain the methods of lubrication

1.HYDROSTATIC LUBRICATION
In hydrostatic lubrication systems, a their film of lubrication is created
between the journal and the bearing by supplying lubricant under pressure with an
external source like pump. Since the lubricant is supplied under pressure, this type of
bearing is called externally pressurized bearing
Compared to Hydrostatic bearing, hydrodynamic bearings are simple in
construction, easy to maintain and lower in initial as well as maintenance.

2. Hydrodynamic or Fluid film lubrication

In heavily loaded bearings such a thrust bearings and horizontal journal pressure is
also required to support the load until the film is established.
If the pressure is generated externally is called as hydrostatic lubrication and if
generated internally in within the bearing by dynamic action, it is referred to as
hydrodynamic lubrication. In this type of lubrication, a fluid wedge is formed by the
relative surface motion of the journals or the thrust runners over their bearing surfaces.
a. Thrust Bearings
In hydrodynamic lubrication, the wearing surfaces are completely separated by a
film of oil. This type of lubrication is similar to motorized speed moving on water.
When not moving the boat begins to move, it experiences a resistance due to the
viscosity of water.
This causes a slight lift of leading edge of the boat and allows a small amount of
water between it and supporting water surface.
As the velocity of boat increases, the wedge shaped water film increases until a
constant velocity is reached.
When the velocity is constant the amount of water entering the leading edge
equal the amount passing outward from the trailing edge.
For the boat to remain above the supporting surface there should exist a upward
 pressure equal to the load. The same principle can be applied to sliding surface.
The operation of thrust bearing is an example of hydrodynamic lubrication. Thrust
bearing assembly used in hydropower industries are also called tilt pad bearings.

The pads of these bearings are designed to lift and to tilt to provide enough area for
lifting the load of generator. As the thrust runner moves over the thrust shoe, fluid adhering
to the runner is drawn between the runner and shoe forming a wedge of oil.
As the velocity of thrust runner, increases the pressure of oil wedge and the runner
is lifted as full fluid film lubrication takes place. When the load high the pressure pumps
are used to provide initial oil film.

JOURNAL BEARING
The operation of a journal or sleeve bearing is also an example of hydrodynamic
lubrication. When the journal is at rest its weight squeezes out the oil film so that the
journal directly rests on the bearing surface. During operation, the journal has the tendency
roll up the side of bearing. So the fluid adhering to the journal is drawn into contact area
and when the speed increases an oil wedge is formed
The pressure of the oil wedge increase until the journal is lifted up
vertically but also pushed to the side by pressure of oil wedge.
When the journal is rotating at a constant velocity, film thickness will exist only at
the left center and not at the bottom of the bearing.

ELASTO – HYDRODYNAMIC (EHD LUBRICATION)

The lubrication principle is applicable to rolling bodies such as tail or roller
bearings, is known as EHD lubrication.
The formation of the lubricant film between mating bearing surfaces is called
elasto – hydrodynamic mechanism of lubrication.
The two major considerations in EHD lubrication are the elastic
deformation of the contacting bodies under load and the hydrodynamic effects forcing
the lubricant to separate the contracting surfaces while the pressure of the load is
deforming them.
The contact between the large end of the roller and the inner race it is called
elasto – hydrodynamic contact or a hydrodynamic contract. As the rib / roller loads are
much lower than the roller / race loads, the film at the rib/ roller end contact is
usually twice as thick on the roller / race contact
 However, scoring and welding may still occur in severe conditions, including
high speeds, viscosity, load or inadequate lubrication, in there conditions, a lubricant
with extreme (EP) pressure additives is to be used to prevent bearing damage.
Even though the lubrication principle of rolling object is different from sliding
objects, the principle of hydrodynamic lubrication can be applied up to certain limits.
An oil wedge similar to hydrodynamic lubrication exists at lower leading edge of
bearing. Adhesion of oil to the sliding element and support surfaces increases pressure and
creates an oil film between two surfaces.
Since the area of contract is extremely small in a roller bearing or ball bearing, the
force per unit area will be extremely high. Under this pressure, it would appear that the oil
could be squeezed from between the surfaces. The viscosity increase and prevents the oil
from being entire squeezed out.

Extreme Pressure Lubrication

Anti-wear agents (chemicals) which are normally used in boundary lubrication
will not be effective beyond certain temperature (250 degree Celsius).
In heavy loading applications oil temperature raises beyond the anti-wear
protection.
Under this situation lubricants containing additives that protect against extreme
pressure called EP lubricants are used.
EP lubrication can be achieved by chemical compounds of phosphorus, sulphur,
chloride or combination of these.

5. Describe the repair cycle

REPAIR
Generally, the maintenance scheduling embraces the following activities.
 Inspection
 Repair
 Overhauling
Hence the term repair does not reflect the actual but only the time duration
consumed to perform the corrective action. Based on the time the repair may be minor one
like adjustment of fasters, adjustment of belt tension, etc, or major one like reconditioning
the bed surfaces, guide ways and cleaning of bearings etc.
 To create maintenance scheduling program, the various maintenance activities
may be classified into four categories which are as follows.
 Inspection (I)
 Minor Repair (R1)
 Medium or major (R2) &
 Overhauling (O)
Repair cycle
The repeated performance of all/ some of the above mentioned activities in
sequence between successive overhauling is termed as Repair cycle”
The figure shown below shows the activities to be carried out during
overhauling of equipments.

(i) Inspection (I)

(iii) Minor Repair (R )
1
(iiii) Medium or Major (R )
2
(iv) Overhauling (0)

It is clear that first an inspection activity is scheduled followed by minor / major

repair activities.
Then an inspection takes place followed by a major repair. Again a second
inspection is followed by major repair. Like this is goes and completes one repair cycle.
The set of their activities between two consecutive overhauling is defined as a
repair cycle.
This typical repair cycle covers three inspection and two minor and major repair
activities. This can be represented O1 – I1 – R1 – R2 – I2 – R1 – I3 -R2
From the above it is understood that the repair cycle is mainly time dependent
between activities.
An index number generally known as repair completely number is used to denote
the complexity of repairing equipments. More the complexity number more will be the
activities involved and in turn more staffing requires to complete the repair cycle.
6. DESCRIBE PILLARS OF TPM
TPM starts with 5S principle. Problems cannot be clearly seen when the workplace
is unorganized. Cleaning and organizing the workplace helps the team to uncover problems.

5S
SEIRI – SORT OUT
This means sorting and organizing the items as critical, important, frequently used
items, useless, or items that are not need as of now.

SEITON – ORGANIZE
Each item has a place and only one place. The items can be identified early by writing
name plates and coloured tags.

SEISO – SHINE
Their involve cleaning the workplace free of burrs, grease, oil, waste, scrap etc. no
loosely hanging wires or oil leakage from machines.

SEIKETSU – STANDARDIZATION
Employees have to discuss together and decide on standards for keeping the workplace/
machines/ pathways neat and clean. These standards are implemented for whole
organization and are inspected randomly.

SHIFTSUKE – SELF DISCIPLINE

This is to bring about self-discipline among employees of the organization. This
includes weaving badges, following work procedures, punctuality, dedication to the
organization etc.
PILLAR 2 – JISHU HOZEN
Also known as autonomous maintenance. The pillar aims at developing operators
capable of taking care of small maintenance tasks themselves, thus freeing up the skilled
maintenance people to expend time on more value added activity and technical repairs.
PILLAR 3 – KAIZAN
“Kai” means change “Zen means good. Means a continuous improvement will be there.
PILLAR 4 – PLANNED MAINTENANCE
It is aimed to have trouble free machines and equipment’s producing defect free
products for total customer satisfaction. This maintenance classified into four “families or
groups” which were defined earlier.

PILLAR 5 – QUALITY MAINTENANCE

It is aimed towards customer delight by getting them from the highest quality through
defect free manufacturing. Focus is on eliminating non- conformances in a systematic
manner. We gain understanding of what parts of the equipment affect product quality
and being to eliminate current quality concerns and then more to potential quality concerns.

PILLAR 6 – TRAINING
It is aimed to have multi-skilled employees whose morale is high and who are eager
to work and perform all the required functions independent and effectively.

PILLAR 7 – OFFICE TPM

It must be followed to improve, productivity, efficiency in the administrative functions
and identify and eliminate losses. This includes analyzing processes and procedures
towards increased office automation. Office TPM addresses twelve major losses.

PILLAR 8 – SAFETY HEALTH AND ENVIRONMENT

This pillar aims at achieving
 Zero accident
 Zero health damage
 Zero fires.
The main objectives are to achieving zero defects zero accidents and zero
breakdowns in all functional areas of an organization. Also the objectives include to
create different team of people to have active participation aiming at minimization
of defects and to inculcate autonomous policy.

8. Compare and difference betweenTPM & TQM

Similarities
In many of the aspects, TPM is found to have similarity with the total quality
management (TQM) program. The following are the similarities between them.
Empowerment of employees to initiate corrective action, bench marking and
documentation. Top level management committed to the program. Long range outlook
perspective.
Dissimilarities

CATEGORY TQM TPM

Objective To have quality To have reliable equipment
Means of achieving Through systematized Through active
participation management employees
Target Minimized defective through Elimination losses and waste
Preventive maintenance
 UNIT- 3 CONDITIONS MONITORING

1. What is equipment health monitoring?

Conditions monitoring is one of the maintenance methods which are used to assess
the health and condition of equipments machines, systems or process by absorbing
checking, measuring and monitoring several parameters. This technique is also called as
equipment health monitoring.

2. List down the factors for increasing the demand condition monitoring
 Increased quality expectations reflected in produces liability legislation
 Increased automation to improve profitability and maintain competitiveness
 Increased safety and reliability expectations
 Increased cost of maintenance due to labour and material cost.

3. List down the key features of condition monitoring.

 Links between cause and effect
 Systems with sufficient response
 Mechanisms for objective data assessment
 Benefits outweighing cost & Data storage and review facilities.
4. Write down the basic steps in condition monitoring.
 Identifying critical systems
 Selecting suitable techniques for condition monitoring
 Setting baselines
 Data collection
 Data assessment
 Fault diagnosis and repair
 System review

5. What are three types of condition monitoring?

a. Subjective condition monitoring
b. Minimized breakdown costs
c. Improved morality of the operating personnel and safety.
6. Mention the various costs involved in costing of condition monitoring mainly
I. Installation cost
II. Operating cost
7. State the advantages and disadvantages and disadvantages of condition monitoring.
Advantages
 Improved availability of equipment
 Minimized breakdown cost
 Improved reliability
Disadvantages
 Gives only marginal benefits
 Increased running cost
 Sometimes difficult to organize

8. State the methods of measuring vibration

 Amplitude
 Frequency
 Phase
9. Name the types of pyrometers.
 Total radiation pyrometers
 Infra red pyrometers
 Optical radiation pyrometers

10. Mention the application of bimetallic strip.

 Bimetallic strips are frequently used in simple ON – OFF switches.
 The bimetal strips are also used in control switches.

11. List down the features of RTD.

 High degree of accuracy
 Resistance thermometer is interchangeable in a process without compensation or
recalibration

12. State the application and limitation of thermisters.

Applications:
 It is used for varying temperatures
 It is used in time delay circuits
 Thermistors are used for temperature compensation.

13. What are two main types of infrared themography?

 Passive thermography
 Active thermography

14. What are the principles very important for the study of eddy current test
 Permeability
 Conductivity
 Material thickness
 Edge effect and end effect
 Lift off
 Fill factor
15. Name some of the methods of leakage monitoring.
 Interstitial monitoring
 level monitoring
 Vapor monitoring
 Liquid Monitoring
16. Mention the effect of X-rays to human body?
 Injuries to superficial tissue
 General effects on the body, particularly the blood forming organs; eg. Producers of
anema and leukerma
 Induction of mahgnant tumors.
 Genetic effects.
17. What are the limitations of ultrasonic test?
 Unfavorable geometries and coarse anisotropic grain structures are difficult to
inspect.
 Extensive technical knowledge is required for the development of inspection
procedure.
 Parts that are rough, irregular in shape, very small or thin or not homogenous are
difficult to examine, specific probes and to interpret the inspection data.
18. Describe the limitation of eddy current test.
 The main limitation is the low penetration of parts being examined, using limited to
thin walls or near surface flaws. It is difficult to use on ferromagnetic materials.
 False indications are possible because of mixed variables, edge effects and lift-off
effects.
 Extensive technical knowledge is required for the development of inspection
procedures, specific probes and to interpret the inspection data.
19. Define see back effect?
The basic principle of thermocouple is ‘when two dissimilar metals are joined
together and emf will exist between the two points A and B, which is primarily a function of
the junction temperature. The above said to be principle of see back effect.

20. State the various methods of corrosion monitoring?

 Weight loss method
 Electrical resistance method
 linear polarization method
 corrosion potential measurement
 Ultrasonic testing
 Sentinel hole method.
Part B
1. Explain the key features of condition Monitoring
The key features of effective condition monitoring system include the following:
(i) Links between cause and effect:
A clear relationship mostly exists between the measurement being taken and the
condition of the equipment.
(ii) System with sufficient response:
The monitoring system must respond quickly enough to provide warning of
deterioration in machine condition for appropriate action to be taken.
(iii)Mechanism for objective assessment
The assessment of equipment condition must be made by comparing readings
against existing measurement and against a predefined and absolute standards
iv) Benefits out weighting Cost
The benefits of performing condition monitoring to predict equipment condition
must outweigh the implementation and running cost.
v) Data Storage and review facilities
A system for measuring and recording data must exist to enable the condition
of equipment to be predicted.

2. Explain briefly the process involved in condition monitoring

Conditions monitoring is one of the maintenance methods which are used to assess
the health and condition of equipments machines, systems or process by absorbing
checking, measuring and monitoring several parameters. This technique is also called as
equipment health monitoring
1. Identifying critical systems
2. Selecting suitable techniques for condition monitoring
3. Setting baselines
4. Data collection
5. Data assessment
6. Fault diagnosis and Equipment repair
7. System review
3. Explain the types of Condition Monitoring
There are three types of condition monitoring as follows:

(i) Subjective Condition Monitoring:

Here the monitoring personnel use their perception of senses and judgment to note any
change of the condition. The guidelines or hints where to look for leakage, bearing play etc.
Posture or figures illustrating different conditions of components may also be helpful.

(ii) Aided Subjective or condition monitoring with simple gadgets:

Here the monitoring personnel are simple gadgets to add their ability to perceive
conditions better. There gadgets are discussed more in detail in the objective condition
monitoring.
(iii) Objective condition monitoring:
Different instruments and facilities are used for obtaining data giving direct
measure of the parametric condition of the components even while the machine is working.

4.Explain the advantages and disadvantages of Condition Monitoring

Advantages
 Improved availability of equipment
 Minimized breakdown costs
 Improved morality of the operating personal and safety.
 Improved reliability
 Improved planning
Disadvantages
 Gives only marginal benefits
 Increased running cost & Sometimes difficult to organize

5. Explain the methods and Instruments for Condition Monitoring

Types Methods On / Off comments
line
Visual Human Eye On / Off It covers a wide range of highly
inspection effective condition checking and surface
inspection methods.

Off Can be used for internal inspection of

machines, good for detecting
surface corrosion, wear and severe
defects line cracks.
Vibration Overall On Represents the vibration of a collating
Monitoring vibration level or reciprocating machine as a single,
number which can be trended and
used as a bases for the detection of
common machine faults.

Frequency On Represents the vibration of a rotating

analysis or reciprocating machine as a
frequency spectrum.

Structural Off A variety of vibration based

Monitoring techniques exists for the
detection and location of
structural faults. The majority of
such techniques involve imparting a
known vibration into the structure
and analyzing the resulting response.
Temperature Temperature On Simple and effective aids to
Monitoring crayons, paints visual inspection.

Thermometers On Range from stock-on thermo metric

strips to permanently installed
thermocouple sensors.

Infra red meter On Non contacting device which measure

radiated body heat to estimate the
surface temperature of a component.
Lubrication Magnetic plugs On / Off Analysis of debris picked up by plugs
analysis & filter or filter in an oil washed system.
Analytical technique used to separate
ferrous debris by size to enable
microscopic examination.

Analytical technique is used to determine

Ferrography N/A the chemical composition of the oil and
debris.

Crack Dye peretrant On / Off Detect cracks which break the surface of
Monitoring the material.
Spectroscopy N/A
Magnetic flues On / Off Detects cracks at / near the surface of
ferrous materials.

Electrical Detects cracks at / near the surface

resistance On / Off and can be used to estimate depth of
crack.

Eddy current On / Off Detects cracks near to surface. Also

useful detection of inclusions and
harness changes.
Ultrasonic On / Off Detects cracks anywhere in a component.

Corrosion Weight loss Off Coupons are weight and weight loss is
monitoring coupon equated to material thickness loss due to
corrosion.

Incremental A series of five plugged holes of

bore holes On incremental depth which are
periodically unplugged and scrutininized
for leakage.

Electrical Electrical element and potentiometers

resistance On are used to assess resistance change
due to material loss. Capable of
detecting material thickness reduction
of loss than one millimeter.
6. Discuss the various levels of condition monitoring?

PARAMETER
S.NO TO MEASURE INSTRUMENT

1 Temperature Pistol therometer,Pyrometer,temperature

sensitive taps
2 Speed & Distance Tachometer,odometer
3 Vibration Accelometer,vibration analyzer
4 Electical quantities Voltmeter, ammeter
5 Wear Thickness gauges
6 Corrosion Corrosion monitor
7 Fits and clearence Proximitymeter

Visual monitoring:
Machine components are visually inspected to determine their condition
a. Sight Leaks Smoke or casing colour change, indicating overheating.
b. Smell Overheating Leaks
c. Hearing Abnormal noise, indicating some malfunction.
d. Feel Abnormal vibration, indicating some malfunction, high casing temperatures,
Indicating overheating
Wear debris and contaminant monitoring.
1. Direct detection of the debris in the oil in the machine optical methods.
2. Electrically conducting filters.
3. Inductive and capacitive methods.
4. Collection of the debris in the machine for regular examination.
5. Existing filtration system.
6. Special filters.
7. Magnetic plugs.
8. Regular sampling of the lubricant for an analysis of its contents.
9. Elemental (spectrometric) analysis.
10. Magnetic particle separation.
11. Automatic particle counting.

8.Explain about on-load and off load condition monitoring

ON-LOAD AND OFF LOAD TESTING
Condition monitoring can be done in two methods via, off-line or one-line. In off-line
condition monitoring, the machine is withdraw from service and disconnected from its normal
supply. Measurement therefore, tended to be taken more infrequently to provide satisfactory
trending data for diagnosing and identifying rapidly developing fault condition. In this system,
monitoring equipment is used parallel to the equipment to be monitored. Various monitoring
points are provided for attaching such equipment as and when needed off load monitoring is for
interior or inaccessible parts which need to be stopped temporarily to check the condition.
 However, there may be several situations like, the two-shift working or the plants temporary shut
down for other reasons, when this class can be conducted without production loss.
Off-line monitoring system can be periodic or continuous. In periodic system, monitoring
equipments are connected during the time of monitoring or taking data or reading and then
removed. In continuous monitoring the monitoring equipments or instruments are connected as
long as equipment operates.
On load monitoring means monitoring or adjusting the parameters while the machine or
equipment is running .thus it is done for superficial, easily accessible and non-interfering parts of
the equipment which can carried out without interruption to the operation of system monitoring
equipment are built in or installed in series with the running equipment. On-line monitoring
system are generally continuous with provision t o by pass.
On line condition monitoring also offers other advantage such as limiting the severity of
any damage incurred, enabling accurate identification of failure causes enabling better business
decision such as those for replacement

9. Explain Wear-debris Monitoring

The lubricant is a powerful source of information on machine condition since, if the oil
deteriorates, then so too does the machine condition; conversely, when the machine condition
worsens, the oil suffers. Oil condition may deteriorate as a result of internal and external
contamination, or through the natural depletion or exhaustion of its active chemical additives.
While the monitoring of oil degradation has been found to have limited success in the monitoring
of small stationary diesel engine, the monitoring of the build-up of internal contamination, such as
wear debris, has been far more reliable. The build-up of wear debris in a machine usually
originates from tribological interactions between the working faces of mechanical contacts such as
bearings, gears, pistons, and other lubricated components-the major causes of mechanical
breakdowns. These mechanical interactions usually result in the generation of minute particles of
metal, metal oxide, or corrosion deposits.
 In addition, a variety of other particles may be found in suspension, such as ingested dirt,
carbon from the combustion process, and polymers and fibers from the filters and gasket materials.
The wear debris found in lubricants has a characteristic composition, shape, size, and
concentration, which can be related to the extent of the surface damage and can consequently
provide information on the condition of the component. The composition indicates which
component is failing, the shape reflects the failure mode, and the size and concentration indicate
how far the failure has proceeded.
Wear-debris monitoring involves the regular assessment of changes in these debris
characteristics by one or more of the many techniques available. The underlying principle of wear-
debris analysis is that the wear debris found in a lubricant will form part of a size distribution that
changes progressively as the surface deterioration increases Regular sampling of the oil therefore
allows one to monitor any significant changes in the size distribution and so to estimate the
severity of the wear. While there are many techniques available for the monitoring of part of the
size distribution, wear-debris monitoring also includes the analysis of other characteristics such as
shape and composition to provide additional information on the wear process.
9. Explain various applications of CMS techniques.
 UNIT IV - REPAIR METHODS FOR BASIC MACHINE ELEMENT

1. Define the term failure.

The term failure may be defined as
 any loss that interrupts the continuity of production
 a loss of assets availability
 the unavailability of equipment
 a deviation from the status quo
 not meeting target expectations
 Any secondary defect.

2. What are the various possible causes for a failure?

 Unexpected and unintentional damage
 Workmanship
 Improper design
 Manufacturing defects
 Incorrect usage of equipment

3. Define failure analysis?

Failure analysis is the process by which information/data about failure occurring in
equipments/ systems are collected and analyzed to find the root cause of failures, andthe causes
are addressed to prevent recurrence of failures.

4. Name the three types of failure models?

 Predictable failure model
 Unpredictable failure model
 Running-In-Failure model

5. What are called age-dependent failures?

Time dependent failures are called age dependent failures.

6. What are predictable failures?

In spite of all the working conditions maintained at same level, the cause of failure will
be random in nature and cannot be assigned to any particular mechanism of failure. This type of
failures is called Unpredictable Failures.

7. What are running in Failures?

Suppose if some components/equipment are installed with unnoticed defects, mayfail in a
short duration after installation than during its useful life. This type offailures is running in
Failures.

8. Define Fault tree diagrams

Fault tree diagrams are logic block diagrams that display the state of a system interms of
the states of its components.
9. Write down the capabilities of Fault Tree Diagram.
 Fault tree analysis and failure modes and effects analysis,
  Design for reliability
 Design for safety
10. Define Event tree Analysis
An event tree is a visual representation of all the events which can occur in asystem. As
the number of events increases, the pictures fans out like the branches of a tree.

11. What is the aim of event tree analysis?

The aim of event tree is to determine the probability of an event based on the outcomes of
each event in the chronological sequence of events leading up to it. By analyzing all possible
outcomes, we can determine the percentage of outcomes which lead to the desired result.

12. Define Root cause analysis?

RCA is a step by step method that leads to the discovery of faults first or root cause.
Every equipment failure happens for a number of reasons. There is a definite progression of
actions and consequences that lead to a failure. An RCA investigation from the end failure
is back to the root cause.

13. Define FMEA?

FMEA is methodology for analyzing potential reliability problems early in the
development cycle where it is easier to take actions to overcome the issues, therebyenhancing
reliability through design.

14. Define Risk Priority Number (RPN)

Risk priority numbers is the product of the numerical severity, occurrence and detection
ratings. RPN = (S) X (O) X (D)

15. Name the factors based on the satisfactory performance of gears/drives.

 Proper design and manufacture of drive
 Selection of proper type and size
 Proper installation
 Proper use of service
 Proper maintenance of unit in it entire life.

16. Name the factors that contribute to tooth breakage.

The common reasons for gear tooth breakage may be due to any of the following reasons
 Fatigue
 Heavy wear
 Overload
 Cracking

17. List some of the inspection performed on gears

 Pitch error
 Axial and
 Radial run out

18. Name some of the geometric properties that are checked for guide ways.
  Straightness
 Flatness
 Parallel both on horizontal and vertical surfaces.

19. What are the factors influence the performance of sleeve bearings.
The following are the factors that affect the bearing performance:
 Dirt
 Fatigue
 Hot Shot phenomenon and
 Crush problem

20. Define Crush

Normally, the bearings are manufactured so that they are slightly longer circumferentially
than the mating housing. The bearing will be elastically deformed during assembly. If the
amount of crush is insufficient, relative motion occurs betweenthe bearing and its bore, which
causes fretting and makes the bearing back a highlypolished or pitted.

PART B

1. Explain briefly about FMEA?

FMEA is methodology for analyzing potential reliability problems early in the
development cycle where it is easier to take actions to overcome the issues, thereby enhancing
reliability through design.
FMEA is a procedure in operations management for analysis of potential failure modes
within a system for classification by severity or determination of the effect of failures on the
system. It is widely used in manufacturing industries in various phases of the product life cycle
and is now increasingly finding use in the service industry. Failure modes are any errors or
defects in a process, design, or item, especially those that affect the customer, and can be
potential or actual. Effects analysis refers to studying the consequences of those failures.

FMEA cycle.
Failure mode:
The manner by which a failure is observed; it generally describes the way the failure
occurs.
Failure effect:
Immediate consequences of a failure on operation, function or functionality, or status of
some item
Indenture levels:
An identifier for item complexity. Complexity increases as levels are closer to one.
Local effect:
The Failure effect as it applies to the item under analysis. Next higher level effect: The
Failure effect as it applies at the next higher indenture level.
End effect:
The failure effect at the highest indenture level or total system.
Failure cause:
Defects in design, process, quality, or part application, which are the underlying cause of
 the failure or which initiate a process which leads to failure.
Severity:
The consequences of a failure mode. Severity considers the worst potential consequence
of a failure, determined by the degree of injury, property damage, or system damage that could
ultimately

ADVANTAGES
Improve the quality, reliability and safety of a product/process
Improve company image and competitiveness
Increase user satisfaction
Reduce system development timing and cost
Collect information to reduce future failures, capture engineering knowledge
Reduce the potential for warranty concerns
Early identification and elimination of potential failure modes
Emphasize problem prevention
Minimize late changes and associated cost
Catalyst for teamwork and idea exchange between functions
Reduce the possibility of same kind of failure in future
2. Explain about Sequential Fault Diagnosis Methods
Sequential Fault Diagnosis Methods
• In sequential fault diagnosis the process of fault location is carried out step by step, where
each step depends on the result of the diagnostic experiment at the previous step.
• Such a test experiment is called adaptive testing.
• Sequential experiments can be carried out either by observing only output responses of
the unit under test (UUT) or by pinpointing by a special probe also internal control points
of the unit under test (UUT) (guided probing). Sequential diagnosis procedure can be
graphically represented as diagnostic tree.

3. Write short notes of fault tree diagram?

FTA is a graphical technique used to determine the various combinations of hardware
(and software) failures and human errors, which can result in an undesirable outcome. The
specified undesirable outcome is referred to as a ‘top event’, where the deductive analysis about
the general conclusions and their causes is often described as a ‘top down’ approach. A Fault
Tree Analysis begins with a construction of a fault tree, relating the sequences of events leading
to the top event. This may be illustrated by considering the probabilities of events and by
constructing a tree with AND and OR logic gates.

Basically, the steps involved in a fault tree analysis are:

1. Define the Top Event
2. Know the system
3. Construct the tree
4. Validate the tree
5. Evaluate the tree
6. Study tradeoffs
7. Consider alternatives and recommend actions

A fault tree analysis can also include human error contribution to the overall system, if
the probabilities for human error are described in the same term as component and hardware
failures.
Thus the main purpose of fault tree analysis is to evaluate the probability of the top event
using analytical and statistical methods. By providing useful information concerning the failure
and its means, efforts can be made to improve system safety and reliability. It also evaluates the
effectiveness and the need for redundancy. Hence, the resulting benefits of fault tree analysis to
project management are reduction of analysis time and precision in identifying and correcting
deficiencies.
Fault tree diagrams are logic block diagrams that display the state of a system in terms of
the states of its components.
4. Explain repair methods of guide ways
The major components, mechanisms and useful devices are being carried and moved
longitudinally or crosswise by the guide ways.
During sliding, a frictional force is developed resulting a shearing effect on the surface
layer. Consequently the effect may change the geometrical properties at the surface of contact
Non-uniformity of wear is caused in a particular zone practically.

Mechanical wears are due to:

1. Misalignment of mating parts
2. Lack of proper lubrication
3. Excessive load, developed in contact services
4. Presence of foreign particles in lubricant
5. Accumulation of dusts on guide ways
6. Absence of proper inspection and maintenance

Maintenance activities:
Regular inspection
Measuring the developed wear
Repairing

Maximum wear Repair method Percentage of relative

recommended labour (manual)
up to 0.2 mm Scraping 100
0.2 to 0.3 mm Grinding (locally or on 35
the planner with
grinding attachment)
over 0.3 mm Machining on planer 60
and subsequent scraping 50
Machining and
subsequent grinding

5. Explain repair methods of bed

MACHINE BED
Most of the machine tool bed are made up of grey cast iron, owing to its ability to absorb/
dampen vibration that may arise during the functioning of machine tool .the most probable
problem that occurs in machine bed may be the cracks. Repair of cracks can be repaired by
riveting and hot clamping.

RIVETING:
Riveting is done with headless copper screws in a definite order based on the size and
length of the crack. Initially a suitable diameter (d) is drilled at the extreme ends of the crack, so
that crack does not extend .then the intermediate holes are drilled at a distance of 1.5d. The
projected ends of the screws are hammered to form rivet head and the riveting is strengthened.
HOT CLAMPING:
Over the location of the cracks on cast iron bed two pieces of plates are placed and bolted
with special type and tightened till the shank portion shear off. The welding is done at the end
faces of the two plates while the welding is cooling down, the shrinkage of plates keep the cracks
closed up.

6. Write short notes on logical and sequential fault location methods

Logical fault refers to the effect of physical fault on the system

The necessities of logical fault location are

 The complexity of the system is reduced for further analysis
 One logical fault model is applicable to many technologies
 Logical Fault test may be used for physical faults whose effect is not thoroughly
understood
Logical fault may be explicit or implicit. Explicit fault may be enumerated but implicit fault
are denoted with charactering properties. Sometimes the logical fault is considered as structural
or functional one. Structural faults are related to structural models. They modifies the inter
connection between the components. At the same time functional faults are related to functional
models. They modifies the function of the components.
In sequential fault location diagnosis the process of fault location is carried out step by step,
where each step depends on the result of the diagnostic experiment at the previous step.
Sequential experiment can be carried out by pinpointing the special probe also internal control
points of the UUT Sequential diagnosis procedure can be graphically represented as diagnostic
tree.

7. Write short notes on repair methods for spindles

Wear out places Repair methods

1. Shanks and journal seats Lapping the bearing seats Grinding

2. Spindle taper bore Grinding Compensating bush

for larger wear Spindle reversal
3. Threads for chuck seat & Re- threading on reduced diameter
threads for regulating the Metallization
bearings
4. Key ways and splines Oversize the keyway/New keyway at
Diametrically opposite end Weld
deposition
8. Write short notes on repair methods for slide ways/ guide ways
The slide ways/guide ways is a part of machine tools which are used to offer smooth
sliding motion between mating surfaces.
The following are the most common methods (depending on the value of wear)
1. Scraping
2. Pouring “Stellon” compound (Microcrystalline hydroxyapatite compound)
3. Machining the guide surfaces, installing hylam packing's and then scraping.

9. Write short notes on Repair methods for Bearings

S.No Bearing defects Repair method

1 Bearing inner race loose on 1.Knurling 2.Chromium plating
shaft 3.Metal deposition by welding
4.Metalization 5.Installing a sleeve
6.Welding a new shank at the end sections
2 Housing bore loose on shaft 1.Internal knurling 2.Installing a sleeve
3.Pouring stellon compound
3 Bearing running dry always be kept well lubricated with oil/ grease

4 Mis-alignment Aligning the two units properly

5 Damaged one or more balls should be replaced by new one
/rollers, damaged running
race, deformed separator
6 Radial play when radial play exceeds the limit –replace when
it exceeds the limiting value

10. Write short notes on repairs for lead screw and nut

S.NO DEFECT REPAIR METHOD

1 Lead screw repairs: 1. Clean both the sides on the lathe along the whole
Thread wear up to length.
0.3mm. 2. Reduce the lead screw & cut new threads
3. Reverse the lead screw –less worn out – falls in
working zone.
2 Lead screw repairs: 1.The lead screw is either replaced completely/partly
Thread wear exceeding 2. In the latter case, the worn out section is cut-off and
0.3mm replaced by new one
3 Repairs to lead nut 1.Bi-metalling-If the nut is steel/CI body with
layer of bronze lining-Then machining & cut threads
2. Pouring “Stellon” compound
11. Write short notes on Repair methods for gears

S.NO DEFECT REPAIR METHOD

1 Uniform tooth face wear on (i) Turn over gear
(i) one side (ii) Cutting & welding ring
(ii) Both its sides
2 Broken teeth (i) Welding-using copper template
(i) of module over 4 (ii) Weld filling & Machining
(ii) of module less than 4
3 Burrs on the bore, key way, splines, Clean with a scraper or file
& tooth surfaces, edges of the shifting
4 gears
5 Cracked/ damaged -Defective portion machined away & fitted
Rim or bore of the gear wheel with new machined- locked by welding or
set screws installed
6 Worm and worm wheel repair -reversed
-replace one part
 UNIT V - REPAIR METHODS FOR MATERIAL HANDLING EQUIPMENT

1. State few examples of material handling equipments.

Material handling equipments include carts, hand trucks, fork lifts, conveyors, shelf
pickers and other specialized industrial trucks powered by electric motors orinternal
combustion engines.

2. State the benefits of proper maintenance of material handling equipments.

The benefits of a maintenance program for material handling equipments are to maintain
the high efficiency, keep them in running condition, reduce the cost of repairs, safer operation
and enhanced productivity.

3. State the major stages in preventive maintenance of material handling equipments.

There are three stages of preventive maintenance are:
 Inspection
 Repair and
 over haul

4. State the various phases present in a good maintenance management system.

 Work identification
 Planning
 Scheduling
 Execution
 Recording and
 Analysis

5. Define the term computerized maintenance management system (CMMS)

computerized maintenance management system is the application of computers in
planning, scheduling, monitoring and control of maintenance activities.

6. State the objectives of CMMS.

 Maintenance of existing equipments
 Inspection and service of the equipment
 installation or revamping of the equipment
 Maintenance storekeeping
 Craft administration

7. State the advantages of CMMS.

 Improve maintenance efficiency
 Reduce maintenance costs
 Reduce the equipment downtime by proper scheduling preventative maintenance.
 provide maintenance reports in specific formats depending on the requirements.
 Quicker access to plant maintenance statistics
8. Define work order system.
Work order system is the information system used by the industry to keep track of its
maintenance works.

9. Mention the use of work order backlog.

Work order back log is used to find out all active maintenance works order in an industry.

10. What is work permit?

Work permits are components of work order. Maintenance department issues work
permits to different executing agencies permitting them to start their work.

11. What is job card?

Job cards contain necessary details for performing individual job in
maintenanceorganizations. Job card may be in the form of a card, sheet or printout.

12. State the benefits of job card system.

 Information about maintenance history
 Knowledge of frequency of frequency of maintenance for equipments
 Details of equipments which require maximum resources
 Helps in job auditing
 Evaluation of cost of maintenance.

13. State the role equipment records in maintenance.

Equipment records are information containing the details of installation, service, repair,
maintenance activities, schedules and plans for future implementation.
Equipment records are to be used to maintain control on maintenance cost, reliability and
availability.

14. State the benefits of keeping equipments records.

 Clear picture about the details of maintenance programmes is obtained.
 Information about completed, pending and regular jobs carried out to the equipment are
available
 Records disseminated to various units of the industry.
 Helps in standardization of procedures.
 Evaluation of performance of maintenance tasks.
 Part B

1. Explain the detail repair methods for material handling equipment?

The proper maintenance of material handling equipment is extremelyessential for

preventing the occurrence of bottlenecks or points ofcongestions. Production line flow can be
maintained only if the materialhandling equipment is in proper working order. Out of many
maintenancetechniques available, preventive maintenance is the one of the best maintenance
techniques suggested in case of material handling equipment.

These are three stages of preventive maintenance and they are

 Inspection
 Repair
 Overhauls

Maintenance strategies for hoists and cranes:

Portable crane:
 It is necessary to keep loads within design limits on portable cranes that are mounted on
wheels platforms.
 Frequent inspection of brakes, load hoisting and lowering mechanism
 Inspection of boom, base and platform for any sign of stress
 Eg: cracks, bends, breaks
Overhead cranes:
 Keep the attachments in overhead cranes loaded within the ratingcapacity.
 Maintain safety factors for replacement parts according tomanufacturer specifications
 Check welded connections for cracks, bends abrasion and corrosion

Maintenance strategies for conveyers:

 Conveyer system need to be inspected on a regular basis. The important areas include
rollers, bearings chains and belts. All of these moving parts are subjected to wear and tear
 Check conveyers to detect any bolt slippage, dragging or defective rollers.
 Moving equipment parts are subjected to breaks caused by metal fatigue, loose bearing
and obstructions.
A typical scheduled conveyor maintenance plan:
 Check/lubricate all bearings, universal joints, and pulleys.
 Check chain tension, wear and lubricate
 Check sprocket alignment, wear and screw set.
 Check flat belt tension, wear and acing
 Check V-belt tension, wear and sheave alignment.
 Check general condition of system
 Operate entire system after service
 List any items requiring replacement or repair.
2. Explain the general structure of six phases of good maintenance management?

Work Identification

Work Planning

Work Scheduling

Work Execution

History Recording

Analysis

The proper operation of an industry requires appropriate strategies inmaintenance

management.This is ensured by the effective integration of various phases involved in
management.

A good maintenance managementcan be considered as having six phases.

They are
1. Work identification
2. Planning
3. Scheduling
4. Execution
5. Recording
6. Analysis

The important steps in this system approach are

 Codification and cataloguing

 Preparation of history sheet
 Preparation of instruction and operating manual
 Preparation of maintenance manual
 Maintenance operation liaison
 Maintenance work order and permit system
 Job execution, monitoring, feedback and control
3. Explain the general structure of computerized maintenance management system?

Computerized maintenance management system is the application of computers

inplanning, scheduling, monitoring and control of maintenance activities.

A computerized maintanance management system includes the following aspects:

 Development of a database
 Analysis of available past records
 Development of maintenance schedules
 Availability of maintenance material
 Feedback control system
 Project management.

Objectives of CMMS.
 Maintenance of existing equipments
 Inspection and service of the equipment
 installation or revamping of the equipment
 Maintenance storekeeping
 Craft administration
Advantages
 Improve maintenance efficiency
 Reduce maintenance costs
 Reduce the equipment downtime by proper scheduling preventative maintenance.
 provide maintenance reports in specific formats depending on the
 Requirements.
 Quicker access to plant maintenance statistics
4. Explain the work order flow diagram?

Work order system is the information system used by the industry to keep track of
its maintenance works. Work permits are components of work order. Maintenance department
issues work permits to different executing agencies permitting them to start their work.

A maintenance work orders are generally gives the following information:

 Work order number and code
 Departments address and code
 Date of issue
 Detail of approval
 Date of receipt of work order
 Priority
 Location
 Equipment details
 Nature of work
 Material requirement
 Completion data and report
 Special requirement

Enter Work request

Plan Work request

Approve work plan Work order on Hold parts-

Engineering-Budget

Work order-Ready for Scheduling

Work order-In Process Scheduling

Work order-Completed

Work order-Sent to History

 Work permit are components of work order. Maintenance department issues work
permits to different executing agencies permitting them to start their work. A work permit
mentions the work permit number, work order number, section from which work originated and
information as mentioned in work order.

5. Explain about maintenance monitoring, execution and control?

A well designed organization should have proper strategies to execute, monitor and control
over the various maintenance tasks.
Monitoring:

a) Gather information about deviation and delay in execution of maintenance may provide idea
about the need to add more resources to complete the maintenance task in scheduled time frame
b) Communication of the changes in job content to the various follow up agencies
c) Provide information about constraints in technical issues and necessary steps can be taken to
improve the existing techniques

Method of monitoring:
• Feedback
• Unscheduled / pending job
• Work status
• Suspended work
• Work completion
• Manpower requirements and actual utilization
• Cost of maintenance
• Technical difficulties

Control:

• Continuous or periodical monitoring

• Inspection of status
• Comparison of status with the predetermined standard and initiating corrective measures.
6. Explain about equipment records
Equipment records
Equipment’s records are information containing the details of installation, service, repair,
maintenance activities, conditions, defects, schedules and plans for future implementation.
Equipment records are to be used to maintain control on main, reliability and availability.

TYPES OF EQUIPMENT RECORDS

There are many types of equipment records available industry catering to various needs
they are as follows :
1) Planned work and percentage of planned work achieved
2) Ratio of planned to planned work
3) Production delays & downtimes
4) Ratio of preventive work to corrective work
5) Failure patterns
6) Repetitive breakdown
7) Manuals including operating manual, instruction manuals, maintenance manual and drawings
8) History cards and records
9) Spare cards
10) Maintenance requirement records
11) Performance details
12) cost reports
13) Condition monitoring reports
ADVANTAGES OF EQUIPMENT RECORDS

The following are the advantages of equipment records:

1) Clear picture about the details of maintenance programs is obtained

2) Information about completed pending and regular jobs carried out to the equipment are
available
3) Records disseminated to various units of the industry
4) Helps in standardization of procedures
5) Evaluation of performance of maintenance tasks
6) Provide details of frequency of maintenance requirements for each equipment
7) Comparison of time taken for completing the maintenance job with the past records
8) Provide strategies for better maintenance management.

Types of Equipment Records

There are many types of equipment records available in industry catering to various needs. They
are as follows.
i. Equipment history cards and records
ii. Planned work and percentage of planned work achieved
iii. Ratio of planned to performed work
iv. Production delays and downtime
v. Ratio of preventive work to corrective work
vi. Failure patterns
vii. Repetitive breakdown
viii. Manuals including operating manual, instruction manual, maintenance manual, job
manual and drawings
ix. Spare cards
x. Maintenance requirement records
xi. Performance details
xii. Cost reports
xiii. Condition monitoring reports.

6. Explain about job card

• It is essential to prepare a job card for each equipment/component to record the

maintenance work carried out or the work to be done.
• Job cards contain necessary details for performing individual job in maintenance. Job
card may be in the form of a card, sheet or printout.
• For smaller units, job cards can be made manually or through computers. For bigger
industries, it can be generated by using CMMS software.
Job card contains the following information.
(i) Equipment code and shop code
(ii) Job code
 (iii) Nature of job and job details
(iv) Initiation time
(v) Job start and completion time
(vi) Man hours spent
(vii) Constraints/ deviations.

7. Explain about the Repair of wire rope

Wire rope on cranes normally lost for about 5 years. The wire rope is considered
for replacement during the following situations. If the wire ropes have a number of
broken outside wires & the distribution/concentration of such broken wires.
Condition for replacement is:
12 randomly distributed broken wires in one rope lay or 4 broken wires in one
strand in one rope lay in hoist ropes.
When wear of 1/3 of the original diameter of outside individual wires occurs.
Kinking, crushing, bird caging or any other damage results the distortion of the
rope structure.
If corroded, cracked, bent, worn, improperly applied end connections occur.