EET 481 Electrical Installation and Maintenance

In modern industries, equipment and machinery are very important parts of the production
activity. A large amount of money is invested in machineries and equipment. Special purpose
and modern machineries cost a lot of money. If those machineries and equipment are kept
idle, then it will be a great loss to that company. So, they must be kept always in good
working condition. Then only they will work efficiently for a greater number of years. They
should not breakdown or stop production. So, it is very important that machineries and
equipment in plants are properly maintained. To take smooth production of finished goods
from the factory, machinery and equipment, should be in proper conditions and with
breakdown free. The damage caused to plant and machineries due to normal wear
and tear, improper use, under and over utilization, miss-operation etc. can be viewed
seriously and can hamper the smooth production of goods and services and machine down
time. Keeping the productive resources of plant, machinery, equipment etc. in good working
condition is an important responsibility of management to achieve specified level of quality
and reliability of operation.

Maintenance –Definition
Maintenance is the process of keeping the machine and equipment in good working condition
so that the efficiency of machine is retained and its life is increased.
Or
“Plant maintenance is a combination of actions carried out by an organization to replace,
repair service the machineries, components or their groups in a manufacturing plant, so that it
will continue to operate satisfactorily”
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Objective of plant maintenance
The objective of maintenance is to maximize the performance of productive resources of an
organization by ensuring that these resources perform regularly and efficiently. This is
achieved by preventing the breakdown and failures and by minimizing the production loss.
The main objectives of plant maintenance are:
 To maximize the availability of plant, equipment and machinery for productivity through
planned maintenance.
 To extend the life span of the plant, equipment, machinery etc., by minimizing their wear
and tear and deterioration.

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 To reduce the cost of production due to plant breakdown due to improper plant
maintenance.
 To help the production department to go ahead with their production plans without any
problem.
 To ensure operational readiness of all production facilities for emergency use at all times,
such as firefighting equipment, first aid facilities, alternative method of production and
packing etc
 To provide management with proper information on the cost and effectiveness of
maintenance.
 To ensure safety of staff through regular inspection and maintenance of facilities such as
boilers, compressors, elevations, material handling system, conveyors, dangerous heavy
machineries etc.

FUINCTIONS OF PLANT MAINTENANCE

The basic function of any maintenance activity is to maintain the facility and its equipment in
a condition to meet normal operating requirements. The basic function of maintenance are as
follows
a) Inspection
b) Repair
c) Overhaul
d) Lubrication
e) SalvageHIPLUS.COM
a) Inspection
Inspection involves periodic checking of machines and equipment to ensure safe and efficient
operation, making certain that equipment requiring work at specified periods receives proper
attention, determination of repair feasibility and control of the quality of work accompanied
by maintenance group, Inspection implies detection of faults before they develop in to
breakdown of the equipment.
This can be done effectively by increasing our ability to identify the initial symptoms of
machine trouble as early as possible. The initial symptoms of the machine trouble may be
revealed through noise, vibration, dirtiness, leak or heat of the machine.
b) Repair

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When any item or components fails or breakdown, then the process of repairing the
component or replacing the item or part by another item to restore the item in working order
is known as repair.
c) Overhaul
This is another routine and regular maintenance function falling under preventive
maintenance. The frequency of overhauling is for less than lubrication and inspection. In
overhauling, the machine is stripped and the various parts are cleaned and oiled and
components are replaced.
d) Lubrication
Proper lubrication plays a vital role in maintaining the machine accuracy and increasing its
life. Lubrication of machinery should be considered as important as blood circulation in the
human body. The cleaning and lubrication of the machine is normally done by the operator
itself. From the suppliers document, lubricating instructions showing the daily/
weekly/fortnightly/monthly/ Yearly lubricating points and grades of lubricants to be used
should be prepared. These are tabulated in a chart and explained to the operator
For the convenience of the operator, it is advisable to paint the lubricating points on the
machine. Grade of lubricant and the lubricating schedule may be indicated there itself.
e) Salvage
Any equipment is said to be salvage when it cannot be repaired or cannot be brought to
desired level of performance. In that case the item is to be replaced by new one to bring back
the system into operation.

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BASIC MAINTENANCE TRIGGERS
Maintenance triggers are used to alert technicians that maintenance is required on an asset.
Planning, acting on and recording maintenance triggers is key to keeping equipment at its
best and available when you need it, while avoiding extra work. Leveraging technology, like
a CMMS, is a key component of creating, tracking and executing effective maintenance
triggers.
The five most common types of maintenance triggers
There are five common types of maintenance triggers: breakdown, time-based, event-based,
usage-based, and condition-based. It’s important to understand when and how to use each one
to achieve maximum efficiency and reliability at your facility.
Breakdown trigger
As its name suggests, a breakdown maintenance trigger occurs when a piece of equipment
breaks down and can’t be used anymore. The moment an asset stops working, an alert is
triggered and maintenance is scheduled to fix the problem and return the equipment to
operation.
Breakdown maintenance triggers are a clear sign that a run-to-failure maintenance strategy is
being used for an asset. There are no preventive measures in place to stop failure before it
happens. Instead, equipment is allowed to operate until it breaks down and only then is
maintenance scheduled. While maintenance is not scheduled when using a breakdown
maintenance trigger, a plan is still in place to manage the breakdown. For example, a light
bulb is allowed to operate until it goes out, which triggers a maintenance order that can be
fulfilled quickly because extra light bulbs have been stocked for this exact scenario.
Breakdown triggers are usually put in place on non-critical assets that can be replaced or
fixed quickly with little cost or effect on production with planned stock availability.
Maintenance types that use breakdown triggers: corrective, reactive, run-to-failure
Time trigger
Time is one of the most frequently used maintenance triggers. Here’s how it works: an asset
is scheduled for maintenance on a predetermined schedule, such as the first of every month or
every 14 days. When that time arrives, a maintenance work order is triggered, a technician is
alerted and the maintenance task is completed. Time triggers come in many different shapes
and sizes, from an hourly indicator to a seasonal one.
Time-based maintenance triggers are part of a preventive approach to maintenance. By
scheduling maintenance at regular intervals, it helps ensure assets are functioning properly

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with a minimal amount of unplanned downtime. Using time triggers, small problems can be
caught and fixed before they grow into bigger ones and lead to costly equipment failure.
Time-based maintenance triggers are best used for simple tasks, such as oil changes, and on
assets that have an established best-before date, such as air conditioning filters that need to be
changed every spring.
Maintenance types that use time triggers: preventive, condition-based, predictive
Usage trigger
Usage-based maintenance triggers occur when as asset requires maintenance after operating
at a certain output. A belt may need to be inspected after 100 hours of production, tires could
be checked after 10,000km and induction sealing equipment might require maintenance after
20 production cycles. Whatever the case, when the asset meets this usage point, a work order
is triggered and maintenance is scheduled.
Usage triggers are another hallmark of a preventive maintenance strategy. Rather than wait
for an asset to deteriorate and fail with the strain of use, a trigger is identified to prevent
unplanned downtime from happening. That belt is inspected after 100 hours so it doesn’t stop
working in hour 101 or hour 150 or whenever you need it most.
Time-based maintenance triggers are best used on assets that are critical for production, are
either heavily or irregularly used and have identifiable, usage-based failure rates, such as
drills at a mining operation.
Maintenance types that use usage triggers: preventive, condition-based, predictive
Event trigger
This type of maintenance trigger boils down to one sentence: if this event happens, it triggers
that kind of maintenance. Just add a specific scenario and corresponding maintenance tasks.
When the event is added into a digital maintenance system, like a CMMS, a series of tasks
are triggered to help minimize the negative impact of the event or ensure assets function
properly during the event. For example, if the basement of the facility floods, the electrical
systems must be checked, or, if an audit is scheduled, certain assets must be inspected.
By its very nature, an event trigger is part of a planned, reactive maintenance strategy. Many
events are unforeseen, but that doesn’t mean you can’t plan for the unexpected. Creating
event-based triggers help maintenance teams build a blueprint for emergencies or a sudden
adjustment, so tasks can be completed quickly, assets can be maintained properly and parts
are on-hand when needed.

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Event-based triggers should be used on critical assets that are prone to impact by external
forces. For example, equipment at a facility susceptible to hurricanes or an asset with a higher
emissions output that might be subject to new environmental laws.
Maintenance types that use event triggers: preventive, condition-based, predictive
Condition trigger
When a certain element of an asset is not working the way it’s supposed to, it could mean
something bad is about to happen. When a condition-based maintenance trigger is in place, it
identifies the problem areas and alerts a technician that maintenance needs to be performed.
For example, an engine may be overheating or a bearing on a conveyor belt may be vibrating
too much, which could lead to the entire piece of equipment breaking down. When these
conditions are discovered, maintenance tasks are triggered, so the engine can be cooled down
or the bearing can be tightened.
Condition-based maintenance triggers are part of a well-planned preventive maintenance
program. If a piece of equipment isn’t functioning right, it can be checked, adjusted and
returned to normal operation without much expense or time instead of experiencing a costly
and time-consuming failure. Various techniques are used to monitor the condition of an asset,
track condition triggers and act on. These methods can range from inexpensive (visual
inspections) to more expensive, technically demanding ones (vibration and thermographic
analysis). Condition triggers are the most complex triggers for maintenance. This is because
data about the condition of each asset must be obtained and interpreted. The equipment
required to perform condition monitoring often requires specialized training and experience
to operate effectively. This is why condition-based triggers are best used on very critical
assets that have predictable failure conditions and can integrate condition monitoring
methods into their operation.

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MAINTENANCE PRACTICES
Outlined below are the more widely used maintenance management strategies, as well as
their pros and cons and situations when they are best applied. Typically we see plants
employing either run-to-failure (only fix after a breakdown) or preventive maintenance (on a
predetermined schedule). However, depending on the value of the asset or its criticality in the
plant’s operations, we may see this strategy escalated to predictive or even RCM-based
maintenance.

1. RUN-TO-FAILURE (BREAKDOWN MAINTENANCE)

The simplest maintenance strategy is to execute run to failure maintenance (also known as
“run to fail”). In this strategy, assets are deliberately allowed to operate until they break
down, at which point reactive maintenance is performed. No maintenance,
including preventive maintenance, is performed on the asset up until the failure event.
However, a plan is in place for ahead of the failure, so that the asset can be fixed without
causing any production issues.
Under the run to fail method, it is important to have spare parts and staff on hand to replace
the failed part and to maintain equipment availability. This strategy should not
be confused with reactive maintenance, because of the active plan to allow the
asset to run to failure. This strategy is useful for assets that, on breakdown, pose
no safety risks and have minimal effect on production.
A common example of run to failure maintenance is the maintenance plan for a
general-purpose light bulb. The bulb is allowed to run until it fails. At this time, the plan to
fix the asset is carried out. A new light bulb is obtained from stocks and replaced at a
convenient time.
Advantages
1. Minimal planning – Since maintenance does not need to be scheduled in advance, the
planning requirements are very low. Maintenance only needs to happen after breakdown
has occurred.
2. Easy to understand – Because of the plan’s simplicity, this system is easy to understand
and implement.

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Disadvantages
1. Unpredictable – Because most asset failures are unpredictable, it is difficult to anticipate
when manpower and parts will be needed for repairs.
2. Inconsistent – The intermittent nature of failures means efficient planning of staff and
resources can be difficult.
3. Costly – All costs associated with this strategy need to be considered when it is
implemented. These costs include production costs and breakdown costs, in addition to
direct parts and labour costs associated with performing the maintenance.
4. Inventory costs – The maintenance team needs to hold spare parts in inventory, to
accommodate for intermittent failures.

2. PREVENTIVE MAINTENANCE (PM)

Preventive maintenance (or preventative maintenance) is maintenance that is regularly
performed on a piece of equipment to lessen the likelihood of it failing. It is performed while
the equipment is still working so that it does not break down unexpectedly. In terms of the
complexity of this maintenance strategy, it falls between reactive (or run-to-failure)
maintenance and predictive maintenance.
Examples of preventive maintenance
Preventive maintenance can be scheduled on a time or usage based trigger. Let’s look at an
example for each. A typical example of a time-based preventive maintenance trigger is a
regular inspection on a critical piece of equipment that would severely impact production in
the event of a breakdown.
Usage-based triggers fire after a certain amount of kilometres, hours, or production cycles.
An example of this trigger is a motor-vehicle which might be scheduled for service every
10,000km.
Suitable preventive maintenance applications
Assets suitable for preventive maintenance include those that:
 have a critical operational function
 have failure modes that can be prevented (and not increased) with regular maintenance
 have a likelihood of failure that increases with time or use
Unsuitable preventive maintenance applications
Unsuitable applications for preventive maintenance include those that:
 have random failures that are unrelated to maintenance (such as circuit boards)
 do not serve a critical function

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Advantages of preventive maintenance
Advantages compared with less complex strategies
Planning is the biggest advantage of a preventative maintenance program over less complex
strategies. Unplanned, reactive maintenance has many overhead costs that can be avoided
during the planning process. The cost of unplanned maintenance includes lost production,
higher costs for parts and shipping, as well as time lost responding to emergencies and
diagnosing faults while equipment is not working. Unplanned maintenance typically costs
three to nine times more than planned maintenance. When maintenance is planned, each of
these costs can be reduced. Equipment can be shut down to coincide with production
downtime. Prior to the shutdown, any required parts, supplies and personnel can be gathered
to minimize the time taken for a repair. These measures decrease the total cost of the
maintenance. Safety is also improved because equipment breaks down less often than in less
complex strategies.
Advantages compared with more complex strategies
A preventative maintenance program does not require condition-based monitoring. This
eliminates the need (and cost) to conduct and interpret condition monitoring data and act on
the results of that interpretation. It also eliminates the need to own and use condition
monitoring equipment.
Disadvantages of preventive maintenance
Disadvantages compared with less complex strategies
Unlike reactive maintenance, preventive maintenance requires maintenance planning. This
requires an investment in time and resources that is not required with less complex
maintenance strategies.
Maintenance may occur too often with a preventative maintenance program. Unless, and until
the maintenance frequencies are optimized for minimum maintenance, too much or too little
preventive maintenance will occur.
Disadvantages compared with more complex strategies
The frequency of preventative maintenance is most likely to be too high. This frequency can
be lowered, without sacrificing reliability when condition monitoring and analysis is used.
The decrease in maintenance frequency is offset by the additional costs associated with
conducting the condition monitoring.

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 3. PREDICTIVE MAINTENANCE

The aim of predictive maintenance (PdM) is first to predict when equipment failure might
occur, and secondly, to prevent the occurrence of the failure by performing maintenance.
Monitoring for future failure allows maintenance to be planned before the failure occurs.
Ideally, predictive maintenance allows the maintenance frequency to be as low as possible to
prevent unplanned reactive maintenance, without incurring costs associated with doing too
much preventive maintenance.
How does predictive maintenance work?
Predictive maintenance uses condition-monitoring equipment to evaluate an asset’s
performance in real-time. A key element in this process is the Internet of Things (IoT). IoT
allows for different assets and systems to connect, work together, and share, analyze and
action data
IoT relies on predictive maintenance sensors to capture information, make sense of it and
identify any areas that need attention. Some examples of using predictive maintenance and
predictive maintenance sensors include vibration analysis, oil analysis, thermal imaging, and
equipment observation. Visit our condition-based maintenance page to learn more about these
methods.
Choosing the correct technique for performing condition monitoring is an important
consideration that is best done in consultation with equipment manufacturers and condition
monitoring experts.
How facilities benefit from predictive maintenance
When predictive maintenance is working effectively as a maintenance strategy, maintenance
is only performed on machines when it is required. That is, just before failure is likely to
occur. This brings several cost savings:
 minimizing the time the equipment is being maintained
 minimizing the production hours lost to maintenance, and
 minimizing the cost of spare parts and supplies.
Predictive maintenance programs have been shown to lead to a tenfold increase in ROI, a
25%-30% reduction in maintenance costs, a 70%-75% decrease of breakdowns and a 35%-
45% reduction in downtime.
These cost savings come at a price, however. Some condition monitoring techniques are
expensive and require specialist and experienced personnel for data analysis to be effective.

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What is PdM suitable for?
Applications that are suitable for predictive maintenance include those that:
 have a critical operational function
 have failure modes that can be cost-effectively predicted with regular monitoring

Unsuitable applications
Unsuitable applications for predictive maintenance include those that:
 do not serve a critical function
 do not have a failure mode that can be cost-effectively predicted
Advantages of predictive maintenance
Compared with preventive maintenance, predictive maintenance: ensures that a piece of
equipment requiring maintenance is only shut down right before imminent failure. This
reduces the total time and cost spent maintaining equipment.
Disadvantages of predictive maintenance
Compared with preventive maintenance, the cost of the condition monitoring equipment
needed for predictive maintenance is often high. The skill level and experience required to
accurately interpret condition monitoring data is also high. Combined, these can mean that
condition monitoring has a high upfront cost. Some companies engage condition monitoring
contractors to minimize the upfront costs of a condition monitoring program.
Not all assets have failures that may be more cost-effectively maintained using preventative
maintenance or a run-to-failure maintenance strategy. Judgment should be exercised when
deciding if predictive maintenance is best for a particular asset. Techniques such
as reliability-centred maintenance provide a systematic method for determining if predictive
maintenance is a good choice as an asset maintenance strategy for the particular asset of
interest.

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 4. RCM (RELIABILITY-CENTERED MAINTENANCE)

Reliability-centered maintenance (RCM) is a corporate-level maintenance strategy that is

implemented to optimize the maintenance program of a company or facility. The final result
of an RCM program is the implementation of a specific maintenance strategy on each of the
assets of the facility. The maintenance strategies are optimized so that the productivity of the
plant is maintained using cost-effective maintenance techniques.
There are four principles that are critical for a reliability-centered maintenance program.
1. The primary objective is to preserve system function
2. Identify failure modes that can affect the system function
3. Prioritize the failure modes
4. Select applicable and effective tasks to control the failure modes
7 questions that need to be asked for RCM
An effective reliability-centered maintenance implementation examines the facility as a series
of functional systems, each of which has inputs and outputs contributing to the success of the
facility. It is the reliability, rather than the functionality, of these systems that are considered.
The SAE JA1011 has a set of minimum criteria before a maintenance strategy can be called
RCM (Gulati). The seven questions that need to be asked for each asset are:
1. What are the functions and desired performance standards of each asset?
2. How can each asset fail to fulfill its functions?
3. What are the failure modes for each functional failure?
4. What causes each of the failure modes?
5. What are the consequences of each failure?
6. What can and/or should be done to predict or prevent each failure?
7. What should be done if a suitable proactive task cannot be determined?
Hit your targets with RCM
Reliability-centered maintenance identifies the functions of the company that are most critical
and then seeks to optimize their maintenance strategies to minimize system failures and
ultimately increase equipment reliability and availability. The most critical assets are those
that are likely to fail often or have large consequences of failure. With this maintenance
strategy, possible failure modes and their consequences are identified; all while the function
of the equipment is considered. Cost-effective maintenance techniques that minimize the
possibility of failure can then be determined. The most effective techniques are then adopted
to improve the reliability of the facility as a whole.

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Advantages
Implementing RCM increases equipment availability, and reduces maintenance and resource
costs. Jardine and Tsang give an example of a utility company who reduced maintenance
costs by up to 40%
Disadvantages
RCM does not readily consider the total cost of owning and maintaining an asset. Additional
costs of ownership, like those considered in evidence-based maintenance, are not taken into
account, and are therefore not factored into the maintenance considerations.
The RCM process: 7 steps to implement reliability-centered maintenance
There are several different methods for implementing reliability-centered maintenance that
are recommended, summarized in the following 7 steps.
Step 1: Selection of equipment for RCM analysis
The first step is to select the piece of equipment for reliability-centered maintenance analysis.
The equipment selected should be critical in terms of its effect on operations, its previous
costs of repair, and previous costs of preventive maintenance.
Step 2: Define the boundaries and function of the systems that contain the selected
equipment
The equipment belongs to a system that performs a crucial function. The system can be large
or small, but the function of the system, and its inputs and outputs, should be known. For
example, the function of a conveyor belt system is to transport goods. Its inputs are the goods
and mechanical energy powering the belt, while its outputs are the goods at the other end. In
this case, the electric motor supplying the mechanical energy would be considered as part of a
different system.
Step 3: Define the ways in which the system can fail (failure modes)
In step 3 the objective is to list all of the ways that the function of the system can fail. For
example, the conveyor belt may fail by being unable to transport the goods from one end to
the other, or perhaps it does not transport the goods quickly enough.
Step 4: Identify the root causes of the failure modes
With the help of operators, experienced technicians, RCM experts and equipment experts, the
root causes of each of the failure modes can be identified. Root causes for failure of the
conveyor could include a lack of lubrication on the rollers, a failure of a bearing, or a
loosened belt.

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Step 5: Assess the effects of failure
In this step, the effects of each failure mode are considered. Equipment failures may affect
safety, operations, and other equipment. The criticality of each of these failure modes can
also be considered.
There are various recommended techniques that are used to give this step a systematic
approach. These include:
1. Failure modes and effects analysis (FMEA)
2. Failure, mode, effect and criticality analysis
3. Hazard and operability studies (HAZOPS)
4. Fault tree analysis (FTA)
5. Risk-based inspection (RBI)
The most important failure modes will be determined at the conclusion of this systematic
analysis. Ask yourself questions such as “Does this failure mode have safety implications?”,
and “Does this failure mode result in a full or partial outage of operations?”. Your answer is
the most important failure modes that should be prioritized for further analysis. Importantly,
the failure modes that are retained include only those that have a real probability of occurring
under realistic operating conditions.
Step 6: Select a maintenance tactic for each failure mode
At this step, the most appropriate maintenance tactic for each failure mode is determined. The
maintenance tactic that is selected must be technically and economically feasible.
Condition-based maintenance is selected when it is technically and economically feasible to
detect the onset of the failure mode.
Time or usage-based preventive maintenance is selected when it is technically and
economically feasible to reduce the risk of failure using this method.
For failure modes that do not have satisfactory condition-based maintenance or preventive
maintenance options, then a redesign of the system to eliminate or modify the failure mode
should be considered.
Failure modes that were not identified as being critical in Step 6 may, at this stage, be
identified as good candidates for a run-to-failure maintenance schedule.
Step 7: Implement and then regularly review the maintenance tactic selected
Importantly, the RCM methodology will only be useful if its maintenance recommendations
are put into practice. When that has been done, it is important that the recommendations are
constantly reviewed and renewed as additional information is found.

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5. TOTAL PRODUCTIVE MAINTENANCE
Total productive maintenance (TPM) is a strategy that operates according to the idea that
everyone in a facility should participate in maintenance, rather than just the maintenance
team. This approach uses the skills of all employees and seeks to incorporate maintenance
into the everyday performance of a facility.
Who should participate?
Under the Total Productive Maintenance philosophy, everyone from top-level management to
equipment operators should participate in maintenance. But how? Each member of an
organization can contribute in their own way:
Top management & reliability engineers
Management should be involved in TPM by promoting it as a corporate policy.
Reliability engineers also need to be involved, as they can interpret the maintenance
data stored in an organization’s CMMS in order to find relevant metrics and generate
business insights.
Operators
Operators are the owners of a facility’s assets, meaning they need to take
responsibility for the day-to-day maintenance of their machines. This includes the
cleaning and regular lubrication necessary for equipment health. Operators are also
expected to find early signs of equipment deterioration and report them, as well as
determine ways to improve equipment operation.
Maintenance managers and technicians
Maintenance managers and technicians are expected to train and support operators to
meet their goals and perform more advanced preventive maintenance activities. They
are also expected to take responsibility for improvement activities that will impact the
key performance indicators (KPIs) set out by reliability engineers.
Advantages of TPM
When everyone in a facility is thinking about and contributing to maintenance, many aspects
of the facility will change for the better. Teams employing a TPM strategy often experience
the following:
Fewer breakdowns
When machine operators keep an eye out for changes with their equipment, big issues
are more likely to be spotted early, before a breakdown occurs. This lets the
maintenance team get on top of their PM maintenance schedule, rather than always
reacting to emergency breakdowns.

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Safer workplace
Technicians are much more likely to take risks when rushing to fix a breakdown, so
fewer breakdowns generally mean a safer workplace. On top of that, when everyone
keeps maintenance in mind, problems can be spotted and dealt with well before they
become potentially dangerous situations.
Better overall performance
If everyone in a facility is keeping an eye on maintenance, small fixes will stop going
undetected, which helps you move away from reactive maintenance and
get backlog under control. It takes the pressure of small jobs off the maintenance team
so they can concentrate on the bigger jobs, which increases the overall performance of
your facility.
Understanding the foundation of TPM
TPM is built on a “5S” foundation, with eight pillars supporting it. The beginning of
a TPMprogram will focus on establishing the 5S foundation and developing an autonomous
maintenance plan. This frees up the maintenance staff to begin larger projects and perform
more planned maintenance.

5S: What does each “S” stand for?

Each of these five things should be actioned in order to stand up a TPM strategy:
Sort

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 Determine which items are used frequently and which are not. The ones used
frequently should be kept closeby, others should be stored further away.
Systemize
Each item should have one place—and one place only—to be stored.
Shine
The workplace needs to be clean. Without it, problems will be more difficult to
identify, and maintenance will be more difficult to perform.
Standardize
The workplace should be standardized and labeled. This often means creating
processes where none existed previously.
Sustain
Efforts should be made to continually perform each of the other steps at all times.
Once the foundation is laid, then you can move on to establishing the eight pillars of TPM.

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NO MAINTENANCE STRATEGY
Not having a maintenance strategy is the simplest “strategy” to have for asset maintenance.
The absence of a strategy eliminates the need to plan ahead for maintenance.
Unplanned, reactive maintenance is the most likely type of maintenance that will occur.
Despite the fact that no strategy exists, most types of maintenance tasks are still possible. For
example:
 Unplanned, reactive maintenance will occur any time the asset breaks down.
 Preventive maintenance may occur when the operator (or someone else) decides to do it.
This may include lubrication or cleaning. However, this maintenance is unstructured and
does not occur according to a formalized schedule or due to a trigger.
 Predictive monitoring may also occur. For example, a bathroom sink may be subject to
condition monitoring every time it is used. The user may notice a decrease in flow rate,
and initiate preventive repairs for the sink.
Suitable applications
A “no maintenance strategy” may be suitable for homes and home workshops.
Owned equipment may never have had any planning for maintenance strategy. When the
equipment is non-critical and does not pose any safety risk, this strategy may be ideal.
Unsuitable applications
A “no maintenance strategy” approach is unsuitable in most other situations. The risk of
equipment unavailability, or safety issues should prompt some level of thought about a
maintenance strategy.
Triggers used for “no maintenance strategy” maintenance
Many triggers can be used for this type of “no maintenance strategy” maintenance. These,
however, are all characterized by an unstructured and unplanned approach.
Breakdown trigger
Breakdown is the most likely trigger for maintenance. If the asset is required and not
working, then maintenance will be required.
Time trigger
Time may also be used as a trigger. “I haven’t lubricated the machine for a long time” could
be a trigger for maintenance.
Event trigger
An event could be used. A news report of a fire being caused by a similar asset may trigger a
maintenance inspection.
Usage trigger
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A usage trigger may initiate work. A counter ticking over to a significant milestone (say 100
hours) may initiate maintenance by the user if they want to. Importantly, this would not be
pre-planned.
Condition trigger
Condition may also be used. The example of the bathroom sink beginning to run slowly is an
example of this trigger
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Review Questions
1. What is plant Maintenance?
2. What are the specific objectives of any maintenance function of an organization?
3. Differentiate between preventive and breakdown maintenance
4. Explain various types of plant maintenance?
5. Explain the need for plant maintenance
6. Explain in detail the procedure involved in plant maintenance

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 FAILURE ANALYSIS METHODS
Every product or process has modes of failure. An analysis of potential failures helps
designers focus on and understand the impact of potential process or product risks and
failures.
Several systematic methodologies have been developed to quantify the effects and impacts of
failures.
Why perform failure analysis?
i. Product Development:
 Prevent product malfunctions.
 Insure product life.
 Prevent safety hazards while using the product.
ii. Process Development:
 Insure product quality
 Achieve process reliability
 Prevent customer dissatisfaction
 Prevent safety or environmental hazards
Common Failure Analysis Techniques
i. Cause-Consequence Analysis
ii. Event Tree Analysis
iii. Failure Modes & Effects Analysis (FMEA)
iv. Failure Modes, Effects and Criticality Analysis (FMECA)
v. Fault Tree Analysis (FTA)
vi. Hazard & Operability Analysis (HAZOP)
vii. Human Reliability Preliminary Hazard Analysis (PHA)
viii. Relative Ranking
ix. Safety Review

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FAILURE MODES & EFFECTS ANALYSIS
Failure Mode and Effects Analysis (FMEA) is a method designed to:
 Identify and fully understand potential failure modes and their causes, and the effects
of failure on the system or end users, for a given product or process.
 Assess the risk associated with the identified failure modes, effects and causes, and
prioritize issues for corrective action.
 Identify and carry out corrective actions to address the most serious concerns.
The primary objective of an FMEA is to improve the design.
 For System FMEAs, the objective is to improve the design of the system.
 For Design FMEAs, the objective is to improve the design of the subsystem or
component.
 For Process FMEAs, the objective is to improve the design of the manufacturing process.
There are many other objectives for doing FMEAs, such as:
 identify and prevent safety hazards
 minimize loss of product performance or performance degradation
 improve test and verification plans (in the case of System or Design FMEAs)
 improve Process Control Plans (in the case of Process FMEAs)
 consider changes to the product design or manufacturing process
 identify significant product or process characteristics
 develop Preventive Maintenance plans for in-service machinery and equipment
 develop online diagnostic techniques
Types of FMEAs
The three most common types of FMEAs are:
 System FMEA
 Design FMEA
 Process FMEA
System FMEA
Analysis is at highest-level analysis of an entire system, made up of various subsystems.
The focus is on system-related deficiencies, including
 system safety and system integration
 interfaces between subsystems or with other systems
 interactions between subsystems or with the surrounding environment

21
  single-point failures (where a single component failure can result in complete failure
of the entire system)
 functions and relationships that are unique to the system as a whole (i.e., do not exist
at lower levels) and could cause the overall system not to work as intended
 human interactions
 service
Some practitioners separate out human interaction and service into their own respective
FMEAs.

Design FMEA
Analysis is at the subsystem level (made up of various components) or component level.
The Focus is on product design-related deficiencies, with emphasis on
 improving the design
 ensuring product operation is safe and reliable during the useful life of the equipment.
 interfaces between adjacent components.
Design FMEA usually assumes the product will be manufactured according to specifications.

Process FMEA
Analysis is at the manufacturing/assembly process level.
The Focus is on manufacturing related deficiencies, with emphasis on
 Improving the manufacturing process
 ensuring the product is built to design requirements in a safe manner, with minimal
downtime, scrap and rework.
 manufacturing and assembly operations, shipping, incoming parts, transporting of
materials, storage, conveyors, tool maintenance, and labelling.
Process FMEAs most often assume the design is sound

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FMEA Procedure
1. Review and understand product or process design; breakdown into components
(product) or steps (process).
2. Brainstorm modes of failure.
3. Rate the severity of each effect of failure.
4. Rate the likelihood of occurrence for each failure.
5. Rate the likelihood of detection for each cause of failure (i.e. the likelihood of
detecting the problem before it reaches the customer or operator).
6. Compute the Risk Priority Number, RPN = Severity x Occurrence x Detection
7. Implement corrective actions to minimize the occurrence of the more significant
failure modes (i.e. the highest RPN’s).
8. Re-assess the product or process by another cycle of FMEA after the actions have
been completed.
9. Perform regular (re)assessments of failures as needed.
Example: Hydraulic Hose Failure

 Severity, Occurance and Detection ratings are based on a 1 = low to 10 = high scale.
 The FMEA results clearly show the greatest risk is associated with overpressure
failure, and the lowest risk is due to weathering-related failure.

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FAULT TREE ANALYSIS (FTA)
 Graphical model that displays the various combinations of equipment failures and
human errors that can result in the main system failure of interest.
 Identification/assessment of risk is derived by first identifying faults/hazards.
 A top down approach.
Definitions
FAULT: An abnormal undesirable state of a system or a system element induced 1) by
presence of an improper command or absence of a proper one, or 2) by a failure (see below).
All failures cause faults; not all faults are caused by failures. A system which has been shut
down by safety features has not faulted.
FAILURE: Loss, by a system or system element*, of functional integrity to perform as
intended, e.g., relay contacts corrode and will not pass rated current closed, or the relay coil
has burned out and will not close the contacts when commanded –the relay has failed; a
pressure vessel bursts –the vessel fails
Fault Tree Example

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Fault Tree Construction
 Each node in the tree can be represented by a combination of events that cause the
occurrence of the event, by means of logic gates
Each gate has inputs and outputs
An input can be a basic event or an output of another gate
The development of a fault tree model relies on the analyst’s understanding of the system
being analysed
It is very important to understand the system first in order to build a unbiased fault tree
Logic (Boolean) Gates

FTA Structure

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FTA Example

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MEASURES FOR MAINTENANCE PERFORMANCE
As the adage goes, you can’t improve a process without first measuring its performance, but
what are the most important maintenance metrics (KPI) you should measure? Establishing a
baseline for success should be the first step whenever you set out to improve something. Bill
Gates draws the example of the steam engine – one of the biggest advancements in the
industrial age, as being a product of incremental design changes and precise feedback, as
opposed to one Eureka! – type moment. “Without measurement,” writes William Rosen,
invention is “doomed to be rare and erratic.”With the steam engine, the criteria is fairly
straightforward. A superior design would have some combination of being lighter, more
powerful, more fuel efficient, cheaper to construct, etc.
The same is true for maintenance metrics and there is a wealth of performance indicators that
can be used to measure and improve performance. For example,

Minimizing downtime might seem like a worthy goal, but not if it also has a negative impact
of product quality or employee morale. Or, if it jeopardizes a longer term strategy of
increasing the proportion of preventive/reactive maintenance. When optimizing the
department there are dozens of confounding factors to be considered. The struggle then
becomes which maintenance metrics to focus on.
Introducing the balanced scorecard approach
The balanced scorecard approached was first introduced in the early 1990’s and encouraged
managers to track performance using a variety of metrics. The central idea is to avoid
optimizing one area at the expense of another. Increasing machine availability by stocking an
excessive number of spare parts – OEE improves, but inventory costs skyrocket as well. The
age-old practice of measuring performance based solely on financial indicators alone has
been found to be inadequate and missing the whole picture. Hence, a new school of thought
has emerged that reconciles high-level financial measures with more practical day-to-day key
performance indicators (KPIs).

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Balanced scorecards provide a clear and effective approach to capturing a high-level view of
the organization.

*Cost/unit should be defined based on the specifics of your organization. Generally speaking,
it will include some combination of labour, spare parts, overtime, contract labour, utilities,
insurance, etc.
**OEE: Overall equipment effectiveness = (Availability)*(Performance)*(Quality)
This holistic approach to maintenance brings the organization one step closer to integrating
maintenance with other high-level goals and promotes the idea that maintenance metrics
should be viewed as an input to production instead of a necessary waste.

What is maintenance backlog?

Maintenance backlog is made up of work that needs to be completed for safety reasons and
to avoid further asset breakdown (e.g. an oil change for your truck is scheduled for every
5000 miles). When the odometer reading hits 5000 miles and the work is due this task will sit
in your maintenance backlog until it is complete. The longer it sits there, the more precarious
it can become.
Over and under-resourcing labour
While some level of maintenance backlog is acceptable and unavoidable, the appropriate
level of maintenance backlog should be determined in relation to each business
need. Maintenance requires labour and an over resourced crew will have a small maintenance
backlog while a under resourced crew will have a large maintenance backlog that is growing
all the time. The ideal scenario is a maintenance backlog that is stable and controllable, even

28
if the facility was hit with a record number of emergency breakdowns. Maintaining a balance
between resource allocation and the costs associated with maintenance is essential.
How much is too much maintenance backlog?
Maintenance backlog can be determined for the entire maintenance operation or by the asset.
Businesses find that the context and level of risk associated with each particular asset
determines the level of backlog acceptable. Low risk assets tolerate longer maintenance
backlogs while high risk assets tolerate shorter maintenance backlogs.

Maintenance backlog for higher risk assets

Maintenance backlog for higher risk assets can put a healthy business in a dicey situation.
Notable risks include equipment failures, non-compliance with mandatory fire safety
requirements and statutory safety legislation, costs to remove and replace assets, production
losses, and warranties that do not hold up in court.
Fiix combats maintenance backlog
It is diffiult to measure or control maintenance backlog without a computerized maintenance
management system like Fiix. A CMMS helps maintenance managers get a grip on what
work needs to be done, and when by giving them full visibility on backlog or its breakdown.
In the report (right), the supervisor can see how old the work is. The maintenance manager
can also use the maintenance backlog data in the CMMS to determine if they are over or
under resourced. Should they get everyone in on the weekend to close out some older
jobs? By using a CMMS, like Fiix, to track work that is due, businesses can control
maintenance backlog and increase their assets availability and reliability.

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Mean Time to Repair
Definition
Mean time to repair (MTTR) is the average time required to troubleshoot and repair failed
equipment and return it to normal operating conditions. It is a basic technical measure of the
maintainability of equipment and repairable parts. Maintenance time is defined as the time
between the start of the incident and the moment the system is returned to production (i.e.
how long the equipment is out of production). This includes notification time, diagnostic
time, fix time, wait time (cool down), reassembly, alignment, calibration, test time, back to
production, etc. It generally does not take into account lead-time for parts. Mean time to
repair ultimately reflects how well an organization can respond to a problem and repair it.
MTTR formula & how is it calculated?
Expressed mathematically, the MTTR formula is the total maintenance time divided by the
total number of maintenance actions over a specific period.

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Over the lifetime of an asset, each failure will vary depending on the severity of the issue.
Some issues will require a simple parts swap, while others could take days to diagnose and
repair. The frequency vs. repair time plot follows the log-normal distribution. We will have a
large number of repairs that are quick to repair and a small number that take much longer.
Why is mean time to repair important?
For mission-critical equipment, mean time to repair can have a dramatic effect on the
organization’s bottom line. Taking too long to repair equipment can mean product scrap,
missed orders and soured business relationships. To limit the impact of mean time to repair,
organizations have their own maintenance teams, hold spare parts onsite or run parallel
production lines.
What can mean time to repair calculation tell you?
Prediction of the number of hours that a system or component will be unavailable whilst
undergoing maintenance is of vital importance in reliability and availability studies. Mean
time to repair yields a lot of information that can help reliability engineers make informed
decisions such as repair or replace, hire, optimize maintenance schedules, store parts onsite or
switch parts repair strategy. For example, as the system ages, it may take longer to repair
systems. MTTR will trend upwards prompting the repair versus replace decision. Check out
this MTTR example as calculated on the Fiix CMMS reporting dashboard:

You can also use mean time to repair to predict performance or the life cycle cost of new
systems. Equipment manufacturers are now using a modular design philosophy so parts or
subassemblies can be swapped out quickly and easily. Consider being faced with a

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purchasing decision that involves 2 similar systems – one has a higher MTTR because
repairable items are difficult to remove due to their location. The additional time and costs to
maintain should be factored into the life of the system to simplify the purchasing decision.
Manufacturers also use MTTR to justify redesigning or improving systems.
For an accurate MTTR calculation, we must make the following assumptions:
 One technician performs all tasks sequentially.
 Appropriately trained personnel perform the maintenance.
How to improve MTTR
Improving your facility’s MTTR metrics means reducing the mean time to repair for critical
assets. Two critical ingredients for reducing your MTTR are preventive maintenance and
repair efficiency.
Using a preventive maintenance approach will increase asset reliability and availability so
equipment runs longer, failures happen less frequently and maintenance breakdownsaren’t as
severe. When regular checks are done on assets, problems can be identified early, before they
become something worse. Subsequently, MTTR is reduced.
When an asset does break down unexpectedly, having the right tools and processes in place is
the key to fast and efficient repairs, leading to lower MTTR. From being able to quickly
assign work orders to having the right parts on hand, being as organized as possible means
tasks get done on time and get done right, which causes mean time to repair to drop.
Maintenance software, such as a CMMS, is one way to increase repair efficiency and reduce
MTTR. A CMMS contains all the tools necessary to organize, track and fine-tune
maintenance processes and procedures, such as work orders and inventory, so repairs run
smoothly and downtime is minimized.
Mean Time Between Fail (MTBF)
The mean time between fail is an important metric where the failure rate of assets needs to be
managed. It is the average time lapsed between breakdowns of a system. In other words, it is
the average time the system or component functions between breakdowns. For mission
critical or complex repairable assets such as generators, tankers or airplanes, mean time
between fail becomes an important indicator of expected performance. It has also become a
fundamental component in the design of safe systems and equipment. Mean time between fail
does not take into account any scheduled maintenance such as recalibration, lubrications or
preventive parts replacements. Whereas MTTR affects availability, mean time between fail
affects availability and reliability.

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Mean time between fail is usually measured in hours. For accuracy, this measurement
includes only operational time between failures and does not include repair times, assuming
the item is repaired and begins functioning again.
How is MBTF calculated?
There are a number of factors that can influence mean time between fail, mainly human. Was
the product applied in the correct way? Did the actions of the technician during a previous
repair contribute to the failure?

Why is it useful?
Mean time between fail figures are often used to project how likely a single unit is to fail
within a certain period of time. Therefore, MTBF is a great way to quantify the reliability of
a system or component. It refers to the average time the asset functions normally before it
fails so it can be used to predict future performance. Organizations that provide automobile
break down assistance, for example, factor in MTBF when determining pricing. The more
likely the average automobile is to break down, the more they have to charge.

MTBF can also be useful in determining the frequency of inspections or preventive

replacements. If your system is failing for the same reasons, you could use the MTBF data to
introduce some preventive actions such as greasing, inspections, calibrations, preventive
repairs etc.
MTBF is also a important reliability metric and can influence the design of newer systems.
Quality driven manufacturers track failure modes and defects so they can eliminate them
from the design process going forward, improving MTBF over time.

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System availability
We don’t live in a perfect world. Imperfect humans build imperfect machines. An
unavoidable result of this is that the systems and assets we operate fail from time to time.
However, businesses can still function with these imperfect systems if, when we need them,
they are properly functioning. This is called system availability. System availability is the
probability a system is functioning when needed to, under normal operating conditions. When
the system is alive and well, the organization can continue to produce output and meet orders.
The availability equation is as follows:

Availability calculations do not include preventive maintenance downtime. To increase

availability, we can either increase the average time interval between repairs (MTBF) or
decrease the amount of time spent doing the repair (MTTR). Understanding how
maintainability and reliability affect availability is key in maximizing it, however, we must
do this in a cost-effective manner. It is not possible to keep pumping capital into improving
availability and expect linear returns.
What is maintainability?
Maintainability is the ease in which something can be maintained or restored to its
functioning state. It determines how easy it is to isolate bugs or problems within a system
preform the repair. Maintenance can impact maintainability directly by shortening the
MTTR. This could be achieved through training; knowledge transfers, creating standardized
procedures and checklists in your CMMS, creating best practices for troubleshooting, having
the right tools onsite and recoding repair history in your CMMS to review later. As many of

34
these actions can be tracked in Fiix, it can play a large part in improving maintainability.
Maintainability is also one of the most commonly over looked design attributes that can make
the difference between a five-minute swap out and a 1-week rebuild. Modern systems are
designed with modular components so they can be swapped out quickly. A quick example of
this is modern aircrafts compared to pre-jet age models. Older airplanes typically had the
propeller engine house in the fuselage at the front of the aircraft. This made it difficult to
repair due to the positioning and the location of the propellers engine. Modern aircraft have
turbines hanging below the wings that can be swapped in and out in 8 hours if needed. This
means the repair can be completed offline and the aircraft is back flying quickly with the
replacement engine.
Reliability
System reliability is the probability that the asset will be able to execute a failure-free
operation for a managed period of time within normal operating conditions. When reliability
gets out of control, it can lead to a domino effect that engulfs the organization.
For example, it can lead to increase in stock outs; costly emergency parts orders, missed PMs,
collateral damage, manpower shortages and ultimately missed orders. Maintenance can
impact reliability by increasing the time lag between repairs. This can be achieved by
optimizing the preventive maintenance program on an asset or the system. The easiest way is
to include steps to proactively perform inspections so issues are spotted before they turn into
something more serious. The common way to measure reliability is MTBF, which refers to
the average time the asset functions normally before it fails. Maintainability rates are easier to
predict and generally more accurate but reliability has a bigger impact on availability. Long
periods of improved reliability will lead to increased availability. Maintenance doesn’t impact
availability directly; rather it indirectly impacts availability through maintainability and
reliability.
Overall equipment effectiveness (OEE)
Overall equipment effectiveness is essentially how available your equipment is, how it
performs versus its spec and what kind of quality it produces. OEE can be used to monitor the
efficiency of your manufacturing processes and to help identify areas of improvement. In
practice, overall equipment effectiveness is calculated as the product of its three contributing
factors:
OEE calculation: Overall equipment effectiveness = availability x performance x quality
 Availability – The system is functioning when it is needed.
 Performance – A measure of system throughput divided by its maximum throughput.
35
 Quality – The number of good units divided by total units started.
Overall equipment effectiveness excludes planned shutdowns such as preventive
maintenance, holiday shutdowns and periods when there are no orders to produce. When you
subtract this planned downtime from total plant operating time, you are left with planned
production time. OEE is calculated on planned production time. The ideal manufacturing
facility, is one that produces the best product, as quickly as possible, with no unscheduled
down time. This is an OEE of 100% which is difficult, if not impossible to achieve. For
discrete manufacturing plants, world class OEE is generally considered being 85% or better,
however, the average OEE metric is ~60%.
What are OEE metrics used for?
Overall equipment effectiveness is a good indicator of machine or system productivity. It can
also give insights into the behaviours of personnel maintaining the system. A bad
maintenance technician will spend the day running around putting our fires. They’ll fix the
problem but they won’t prevent it from happening again. A good maintenance technician will
perform regular inspections to spot failures before they occur, perform recurring scheduled
maintenance and put in measures to prevent further failure reoccurrence; resulting in less
machine-related downtime. OEE also provides a way of measuring the success of
manufacturing, productivity or lean initiatives such as TPM.

When you identify the 3 different elements that make up overall equipment effectiveness, it is
easier to identify where improvements are possible and where to put your focus. If
availability is the focus, then you can run downtime reports in Fiix and identify which issues
are causing the majority of the system stoppages. In reality, OEE measures the losses that
affect your equipment. The 6 big losses are:
1. Equipment failures
2. Setup and adjustment time due to product changeover
3. Idling or minor stoppages – jams, misfeeds, sensor errors etc.
4. Reduced speed due to rough running or equipment wear
5. Defects in operation or process

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6. Startup or reduced yield
Edge ahead by measuring your OEE
In today’s fast-paced economy, manufacturing organizations need to find ways of creating a
competitive advantage over their competition. Efficiency is one area that every
manufacturing plant can improve on, and the best way to measure efficiency is with overall
equipment effectiveness. If you don’t know your overall equipment effectiveness, then you
don’t know how efficient your plant is. More importantly, you don’t know how efficient
your plant could be.

You can calculate the availability element of the OEE equation using Fiix, but as you can see
from the table above, maintenance activities can impact all 3 elements of OEE. A preventive
maintenance solution, like Fiix software, is the ideal tool to track your schedule maintenance
and inspections so issues can be identified before they turn into something more serious.
According to David Berger of Plant Services, a CMMS could deliver a 10% increase in
availability, a 5% increase in throughput and a 5% increase in quality of output. With a fully
functioning CMMS, coupled with a preventive maintenance philosophy, these gains result in
a significant improvement in OEE and hence the company financials.

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 FAULT DIAGNOSIS AND RECTIFICATION
To diagnose and find faults in electrical installations and equipment is probably one of the
most difficult tasks undertaken by an electrician. The knowledge of fault finding and the
diagnosis of faults can never be completely ‘learned’ because no two fault situations are
exactly the same. As the systems we install become more complex, then the faults developed
on these systems become more complicated to solve.
To be successful the individual must have a thorough knowledge of the installation or piece
of equipment and have a broad range of the skills and competences associated with the
electrotechnical industries. The ideal person will tackle the problem using a reasoned and
logical approach, recognize his own limitations and seek help and guidance where necessary.
The tests recommended by the IEE Regulations can be used as a diagnostic tool but the safe
working practices described by the Electricity at Work Act and elsewhere must always be
observed during the fault finding procedures. If possible, fault finding should be planned
ahead to avoid inconvenience to other workers and to avoid disruption of the normal working
routine. However, a faulty piece of equipment or a fault in the installation is not normally a
planned event and usually occurs at the most inconvenient time. The diagnosis and
rectification of a fault is therefore often carried out in very stressful circumstances.

Symptoms of an electrical fault

The basic symptoms of an electrical fault may be described in one or a combination of the
following ways:

1. There is a complete loss of power.

2. There is partial or localized loss of power.
3. The installation or piece of equipment is failing because of the following:
a. an individual component is failing;
b. the whole plant or piece of equipment is failing;
c. the insulation resistance is low;
d. the overload or protective devices operate frequently;
e. Electromagnetic relays will not latch, giving an indication of under voltage.

Causes of electrical faults

A fault is not a natural occurrence; it is an unplanned event which occurs unexpectedly. The
fault in an electrical installation or piece of equipment may be caused by:

38
  negligence – that is, lack of proper care and attention;
 misuse – that is, not using the equipment properly or correctly;
 abuse

WHERE DO ELECTRICAL FAULTS OCCUR?

1. Faults occur in wiring systems, but not usually along the length of the cable, unless it has
been damaged by a recent event such as an object being driven through it or a JCB
digger pulling up an underground cable. Cable faults usually occur at each end, where
the human hand has been at work at the point of cable inter-connections. This might
result in broken conductors, trapped conductors or loose connections in joint boxes,
accessories or luminaires.
2. Faults also occur at cable terminations. The IEE Regulations require that a cable
termination of any kind must securely anchor all conductors to reduce mechanical
stresses on the terminal connections.
3. Faults also occur at accessories such as switches, sockets, control gear, motor contactors
or at the point of connection with electronic equipment.
4. Faults occur on instrumentation panels either as a result of a faulty instrument or as a
result of a faulty monitoring probe connected to the instrument.
5. Faults occur in protective devices for the reasons given in points 1–3 above but also
because they may have been badly selected for the job in hand and do not offer adequate
protection or discrimination
6. Faults often occur in luminaires (light fittings) because the lamp has expired. Discharge
lighting (fluorescent fittings) also require a ‘starter’ to be in good condition, although
many fluorescent luminaires these days use starter-less electronic control gear.
7. Faults occur when terminating flexible cords as a result of the flexible cable being of a
smaller cross section than the load demands, because it is not adequately anchored to
reduce mechanical stresses on the connection or because the flexible cord is not suitable
for the ambient temperature to be encountered at the point of connection.

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Finding the electrical fault
The steps involved in successfully finding a fault can be summarized as follows:

1. Gather information by talking to people and looking at relevant sources of

information such as manufacturer’s data, circuit diagrams, charts and schedules.
2. Analyse the evidence and use standard tests and a visual inspection to predict the
cause of the fault.
3. Interpret test results and diagnose the cause of the fault.
4. Rectify the fault.
5. Carry out functional tests to verify that the installation or piece of equipment is
working correctly and that the fault has been rectified.

Safe working procedures

1. The circuits must be isolated using a ‘safe isolation procedure’, such as that described
below, before beginning to repair the fault.
2. All test equipment must be ‘approved’ and connected to the test circuits by
recommended test probes as described by the HSE Guidance Note GS 38. The test
equipment used must also be ‘proved’ on a known supply or by means of a proving
unit.
3. Isolation devices must be ‘secured’ in the ‘off ’ position. The key is retained by the
person working on the isolated equipment.
4. Warning notices must be posted.
5. All relevant safety and functional tests must be completed before restoring the supply.

Live testing
The Electricity at Work Act tells us that it is ‘preferable’ that supplies be made dead before
work commences (Regulation 4(3)). However, it does acknowledge that some work, such as
fault finding and testing, may require the electrical equipment to remain energized.
Therefore, if the fault finding and testing can only be successfully carried out ‘live’, then the
person carrying out the fault diagnosis must:

 be trained so that he understands the equipment and the potential hazards of working
live and can, therefore, be deemed to be ‘competent’ to carry out the activity;
 only use approved test equipment;

40
  set up barriers and warning notices so that the work activity does not create a situation
dangerous to others.

Note that while live testing may be required in order to find the fault, live repair work must
not be carried out. The individual circuit or item of equipment must first be isolated.
Secure isolation of electrical supply
The Electricity at Work Regulations are very specific in describing the procedure to be used
for isolation of the electrical supply. Regulation 12(1) tells us that isolation means the
disconnection and separation of the electrical equipment from every source of electrical
energy in such a way that this disconnection and separation is secure. Regulation 4(3) tells us
that we must also prove the conductors dead before work commences and that the test
instrument used for this purpose must itself be proved immediately before and immediately
after testing the conductors. To isolate an individual circuit or item of equipment
successfully, competently and safely we must follow a procedure such as that given by the
flow diagram in Fig below.
Start at the top and work your way down the flowchart. When you get to the heavy-outlined
boxes, pause and ask yourself whether everything is satisfactory up to this point. If the
answer is yes, move on. If no, go back as indicated by the diagram.

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42
Faulty equipment: to repair or replace?
The decision to repair or replace equipment should be based on minimizing the total cost of
the equipment to the business over its remaining lifetime. There are a number of factors to
take into consideration when deciding whether to repair or replace equipment, which we’ve
broken down below.

Cost to repair
 Cost per breakdown
 Direct cost of repair, including cost of removing the broken part, disposing of it,
replacement part cost, and cost of installation and testing
 Cost of lost production, including lost profits from lost production, cost of scrap
materials, impact of the repair on product quality, and miscellaneous costs
 Collateral cost including environmental cleanup, occupational health and safety
costs, legal costs
 One-time cost
 Cost of inventorying spares related to the repair
 Ongoing costs
 Impact of repair on product quality and production capacity, and maintenance costs
over the remaining service life
Cost to replace
 Disposal cost of retired equipment
 Decommissioning and disposal cost
 Salvage value
 Equipment write-off cost (non-cash)
 Cost of purchasing and installing a replacement unit
 Research time, capital equipment cost and spare parts inventory cost, cost of tying
up working capital
 Installation cost including miscellaneous parts and supplies, inspection and
certification costs
 Training & safety meetings prior to deployment
 Lost production during installation and commissioning
 The replacement unit’s impact on production
 Product quality
 Equipment availability

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  Production capacity
 Equipment operating costs
 Labour costs
 Out-of-warranty costs
 Cost of repairs
 Lost production
 Collateral costs
 One-time costs
 Impact on product quality
 Impact on production capacity

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COMPUTERIZED MAINTENANCE MANAGEMENT SYSTEM (CMMS)
While the computerized maintenance management system (CMMS) was created in the 1960s
as a punch-card system used to manage work orders, it’s come a long way in the 50-some
years since. Today, CMMS software is used to easily keep a centralized record of all assets
and equipment that maintenance teams are responsible for, as well as schedule and track
maintenance activities and keep a detailed record of the work they’ve performed.
The evolution of the CMMS to a cloud-based, multi-tenant solution has made it easier than
ever for any maintenance team to harness the power of digital transformation.
What is CMMS software used for?
Tracking work orders: Maintenance managers can select equipment with a problem, describe
the problem, and assign a specific technician to do the work, either from a web or mobile app.
When the machine is fixed, the responsible technician marks the work order “complete” and
the manager gets notified that the work is done.
Scheduling tasks: As a team starts to schedule preventive maintenance, they need a reliable
work calendar. CMMS systems are especially good at scheduling recurring work and sending
reminders to the right people. Organized maintenance scheduling helps even out the
workload for a maintenance team making sure that tasks do not get forgotten.
External work requests: Maintenance teams often have to take a work request from people
outside the team. This can be a request from an assembly line operator who is hearing a
strange noise from a drill or a tenant at an apartment building who is requesting shower
repairs. The CMMS is a central place for recording these requests and tracking their
completion.
Recording asset history: Many maintenance teams have to care for assets that are 10, 20,
even 30 years old. These machines have a long history of repairs. When a problem comes up,
it is always useful to see how this problem was solved last time. In CMMS systems, when
repairs are done, they are recorded in the machine’s history log and can be viewed again by
workers.
Managing inventory: Maintenance teams have to store and manage a lot of inventory that
include things like spare parts for machines and supplies like oil and grease. CMMS systems
let the team see how many items are in storage, how many were used in repairs, and when
new ones need to be ordered. Managing inventory helps control inventory related costs.
Audit and certification: Many CMMS systems keep an unchangeable record of every
action, so an asset’s maintenance history can be audited. This is useful in case of an accident
or insurance claim—an inspector can verify if the proper maintenance was completed on a

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machine. CMMS systems also keep data in a centralized system, which helps keep one
version of the truth for ISO certification.

Benefits of a CMMS
 Measure maintenance performance: A CMMS makes it easy to do preventive
maintenance, which means there are fewer surprise breakdowns and work outages.
Allowing you to make better business decisions.

 Better accountability: Work order tracking makes it possible to quickly see if a

technician did their work on time and get alerted when a task is complete.

 Less overtime: Better scheduling means that your team isn’t sitting idle or
working overtime, which means work can be distributed evenly.

 Information capture: Technicians can record problems and solutions, so this

information is captured for others to use.

 Savings on purchases: Inventory planning features give you the time to shop
around for spare parts pricing, instead of having to buy in a hurry.

 Certification and analysis: A full record of assets and performance helps managers
analyze energy usage and plan maintenance spend.
Who uses the CMMS?
Every industry can benefit from maintenance care, and CMMS software can help businesses
plan and manage that maintenance. There are four key user groups for these systems:
 Production maintenance: These are companies that make tangible products. They
have machines, assembly lines, forklifts, and heavy equipment that require frequent
maintenance.

 Facility maintenance: These are companies that take care of buildings. Apartment
buildings, theatres, and government buildings all require maintenance. CMMS
software helps them deal with structural, HVAC, and water-supply problems.

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 Fleet maintenance: These are companies that take care of vehicles and
transportation. Car rental companies, pizza delivery cars, city buses, transport ships,
and fleets of towing trucks all need to have repairs scheduled, which can be taken
care of with a CMMS.

 Linear asset maintenance: This is a special category of maintenance for companies

that have assets like roads, water pipes, or fiber optic cables that cover great distances.
A CMMS can help manage the complex maintenance required to keep these assets
running.

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 SAMPLE QUESTIONS AND SHORT ANSWERS

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. 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 tn is the time to failure for the Nth specimen. Hence the mean time to
failure for N specimens are
MTTR = (t1+t2+......+tN) /N
6. 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.
7. 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.
8. Define Maintenance Action Rate?
Maintenance action rate is the number of maintenance action that can be carried out on
equipment per hour.
9. State the types of reliability?

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 Reliability can be generally of two types:
i. 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.
10. 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.
11. 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.
12. 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
equipment.
13. 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.
14. 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.
15. Classify various planned maintenance approach.
i. preventive maintenance
ii. corrective maintenance
iii. predictive maintenance
iv. condition based maintenance

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16. 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
17. 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.
18. List the objectives of corrective maintenance?
Elimination break downs Elimination deviations from optimum operating condition.
Elimination unnecessary repairs
19. 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.
20. List down the factors for increasing the demand condition monitoring
i. Increased quality expectations reflected in produces liability legislation
ii. Increased automation to improve profitability and maintain competitiveness
iii. Increased safety and reliability expectations
iv. Increased cost of maintenance due to labour and material cost.
21. List down the key features of condition monitoring.
i. Links between cause and effect
ii. Systems with sufficient response
iii. Mechanisms for objective data assessment
iv. Benefits outweighing cost
v. Data storage and review facilities.
22. Write down the basic steps in condition monitoring.
i. Identifying critical systems
ii. Selecting suitable techniques for condition monitoring
iii. Setting baselines
iv. Data collection
v. Data assessment
vi. Fault diagnosis and repair

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 vii. System review
23. State the advantages and disadvantages and disadvantages of condition monitoring.
Advantages
1. Improved availability of equipment
2. Minimized breakdown cost
3. Improved reliability
Disadvantages
1. Gives only marginal benefits
2. Increased running cost
3. Sometimes difficult to organize

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