Chapter 1

Introduction

Elevators are Vertical transport systems that are utilized for efficient transport of
passengers and goods between different floors (landings). An elevator differs from other
hoisting mechanisms in that it runs at least partially on guide rails. The elevator is a mass
transit system (conveyor) whose design has evolved rapidly from that of a simple drum and
rope traction system to a traction less and machine room less system. Elevator usage has
grown exponentially in India but the adoption of newer technologies such as the MRL drive
or Hydraulic drive systems is lagging behind because of additional costs of maintenance and
inspection involved as convenience of machine room diminishes.

This project through extensive literature review establishes MRL elevators as a superior
choice and aims to provide an alternate configuration of MRL drive hoisting support so as to
provide the advantages of MRL during operation and the convenience of a machine room
during inspection as well as maintenance.
1.1 Project Definition

1.1.1 Aim of the project

The aim of this project carried out at ESCON Elevators Ltd. Is to investigate MRL drives
and design a MRL hoisting support configuration that provides MRL drive elevators the
benefits of a conventional machine room like environment for easy inspection and
maintenance (Quality Control).

1.1.2 Scope of the Project

Scope of the project is to design new configuration of MRL hoisting support by

investigating alternate locations for hoisting beam support which conform to installation
standards. Optimum beam sizes are selected for different passenger capacities and the beam
will be designed and the effect of alternate cabin configurations will be investigated. The new
configuration of support eliminates two major disadvantages of MRL drives i.e high costs of
inspection as well as maintenance and eccentric loads on guide rails.

2
1.2 Elevator Components

The basic components of any elevator system are:

• Elevator hoist way: Hoistway is the space enclosed by fireproof walls and elevator doors
for the travel of one or more elevators. It includes the pit and terminates at the underside
of the overhead machinery space floor or grating or at the underside of the roof where the
hoistway does not penetrate the roof.

• Elevator car or cabin: Elevator Car is the vehicle that travels between the different
elevator stops carrying passengers. It is usually a heavy steel frame surrounding a cage of
metal and wood panels.

• Drive System: Driving machine is the power unit of the elevator, and usually located at
the elevator machine room. The Driving machine used to refer to the collection of
components that raise or lower the elevator.These include the drive motor, brake, speed
reduction unit, sheaves and encoders

• Guide Rails: Guide rails are used to prevent lateral displacement of the elevator and may
be of T or Omega type

• Counter weight: Counter weight is an attached weight that is suspended from cables and
moves within its own set of guide rails along the hoist way walls.

• Control System: Elevator Control System is the system responsible for coordinating all
aspects of elevator service such as travel, speed, acceleration, deceleration, door opening
speed and delay, leveling and hall lantern signals

• Safety Mechanism: Safety devices are located at each landing to prevent inadvertent hoist
way door openings and to prevent an elevator car from moving unless a door is in a
locked position.

3
Figure 1.1: Elevator components [3]

4
1.3 Types of elevators

The different types of elevators based on working principle are:

A. Traction elevators

1. Gearless traction electric elevators

The gearless traction electric elevator could be employed in buildings of any height and
operated at much higher speeds than steam-powered elevators. These elevators typically
operate at speeds greater than 500 feet per minute. In gearless traction machine, six to eight
lengths of wire cable, known as hoisting ropes, are attached to the top of the elevator and
wrapped around the drive sheave in spherical grooves. The other ends of the cables are
attached to a counterweight that moves up and down in the hoist way on its own guiderails.

2. Geared traction elevators

As the name implies, the electric motor in this design drives a worm-and-gear-type
reduction unit, which turns the hoisting sheave. While the lift rates are slower than in a typical
gearless elevator, the gear reduction offers the advantage of requiring a less powerful motor to
turn the sheave. These elevators typically operate at speeds from 38 to 152 meters (125-500
ft) per minute and carry loads of up to13,600 kilograms (30,000 lb). An electrically controlled
brake between the motor and the reduction unit stops the elevator, holding the car at the
desired floor level.

3. Machine Room Less Elevators

Machine Room Less Elevators (usually shortened to as M.R.L. or MRL) are a type of
traction elevator which do not have a machine room at the top of the hoist way. Like normal
traction elevators, M.R.L. elevators use the conventional steel cord ropes used as the hoisting
cables. Some elevator brands (such as Otis, Schindler and ThyssenKrupp) are using flat steel
5
rope belts instead of conventional ropes. Manufacturers using these technology claimed that
with flat steel belt ropes, it saves much space on the hoist way and to allow a minimum size of
the hoisting sheave. With flat steel belts also allows 30% lighter than conventional steel ropes.
Most M.R.L. elevators are used for low to mid rise buildings. M.R.L. elevators in mid-rise
buildings typically serve up to 20 floors.

B. Hydraulic Elevators

Hydraulic elevators are used extensively in buildings up to five or six stories high. These
elevators—which can operate at speeds up to 46 meters (150 ft) per minute—do not use the
large overhead hoisting machinery the way geared and gearless systems do. Instead, a typical
hydraulic elevator is powered by a piston that travels inside a cylinder. An electric motor
pumps oil into the cylinder to move the piston. The piston smoothly lifts the elevator cab.
Electrical valves control the release of the oil for a gentle descent.

6
 Chapter 2

Literature Review

Celik and Korbahti [1] have reported that hydraulic elevators are more suited to small rise
buildings and high capacity applications. Their report after experimentally comparing the
performance of different elevator drives under varying parameters of passenger capacity,
severity of service, travel and speed suggests that Hydraulic elevators have the following
advantages over traction drives in low rise applications

 Hydraulic elevator system has lowest initial cost and maintenance cost for a given
capacity

 More building space utilization as the hydraulic elevator utilises upto 12 % less space than
an equivalent traction elevator

 The hydraulic system imposes zero load on the shaft way and shaft size can be reduced

 Hydraulic elevators are more effective for high load vertical transport like freight
elevators
7
 Lowest cost down speed amongst all elevators as gravity is utilized as the motive force

However Hydraulic elevators have deficiencies and disadvantages in areas that MRL
drives perform well in. Hydraulic elevators have only proven to have an advantage over MRL
drives in low speed, low rise high capacity applications.

Their findings conclude that the share of conventional traction elevators in the market will
fall substantially and that of the MRL and Hydraulic drives will increase. The share of MRL
drives will increase in a much larger proportion than that of Hydraulic drives.

The author studied the performance of Hydraulic, Conventional Traction and MRL
(Machine Room Less) drives for varying conditions of speed, travel, capacity and severity of
service and states that among Hydraulic elevators ,and traction drives, Hydraulic elevators
impose the least load on the hoistway and have least cost of construction and operation
however due to their slow nature and requirement of environmental clearance to dig oil wells
they are only utilised in low rise buildings and other applications where Hydraulic elevators
prove advantageous and traction drives cannot be used. Between conventional traction and
MRL drives, MRLs give better ride quality more efficient performance, better product life
and higher speeds than a similar conventional drive however a conventional drive imposes
load only on the building structure where as an MRL exerts load on the hoisting support and
MRL hoisting support has to be designed accordingly. Though having a higher initial cost
MRL systems are more suitable for use than conventional system. Celik and Kohrbati
conclude by stating that in the near future elevator market will be dominated by MRL and
hydraulic drives sharing a majority of the market share.

The results were summarized as follows

8
 Table 2.1: Comparison of Hydraulic and MRL elevators [1]

Safety Hydraulic MRL

Advantage

Installation Driving equipment is safer easier Drive assembled in the shaft,

and and quicker passersby exposed to danger
maintenance

Relative 89% safe Safety 11%

safety

Cost Hydraulic MRL

Advantage

Equipment Cost is least among all types MRL costs are 30 % higher

Installation Installation costs are lower Installation costs are higher by 25

%

Maintenance Costs are moderate Subjected to degrading working

environment and replacement is
expensive

Energy Energy costs are higher than MRL MRL can be 80% more energy
drives efficient

Relative 63 % savings 37% savings

savings

Other Hydraulic MRL

advantages

Noise Noise is dampened Noise is present due to presence of

MRL in hoistway

Speed Only suitable for low speeds Suitable for high speed applications

Ride comfort Similar to that of MRL Similar to that of hydraulic

Car space Larger car can fit in same space Car size is limited by counterweight
space

Relative Other advantages 53% Other advantages 47%

advantages

Total Relative 65 % 35 %
advantages
and value

9
 Tetlow [2] states that MRL drives offer many design advantages apart from their
advantages in performance over conventional drives. MRL drives provide major space
savings which is very important in high rise buildings. The drive can be mounted on overhead
beams or on guide-rail spanning beams. MRL drives increase the design freedom for
architects and engineers; however it has several design considerations which differ from those
for conventional drives. The interior cab design is dictated by constraints on cab weight due to
smaller size of MRL machines as compared to conventional traction machines; the cab weight
is reduced when compared to traditional traction machines. Different MRL drive locations
have differing ventilation needs. Placement of drive affects the hoistway and mounting the
machine on the guide rails transfers weight down to the pit floor. Suspending the machine
from one or more beams tied into the building in the overhead area impacts structural
calculations.

The author summarises the advantages of MRL elevators as

 Contractor time and materials cost are less for MRL elevators than those for conventional
traction elevators:

1. MRL installations require fewer construction materials and less work time: No well
holes to be drilled; no pits to be waterproofed; no requirement for a structural
machine- room slab.

2. Machines are installed from the ground up, removing the requirement for scaffolding.

3. MRL installations do not require a crane to hoist machine or control equipment to the
installation floor or to hoist a structural machine-room slab as required for traction
elevators. The project management challenges in elevator installation and safety
challenges are eliminated. For instance, hydraulic elevators may require a crane to
place the plunger and cylinder in the well hole.

 Installation process for MRL drive are very visible and provide better control over
installation and erection environment

10
 However MRL has design considerations which defer from that of a conventional drive
housed in a separate machine room, and Tetlow [2] suggests conversion of conventional
system to MRL system should take place by gutting of elevator hoistway and reinstalling
required supports and rails.

Jay [3] suggests more design considerations for elevators. ―The mechanics for calculating
theoretical performance and the criteria used to evaluate the vertical transportation systems
were developed according to the type of building, its occupancy, and its usage. In general,
factors determining proper vertical transportation design include (1) the "quality" of service
and (2) the ―quantity ―of service. Quality of service refers to some type of time measurement
relating to passenger waiting time. Quantity reflects the ability of the elevator or escalator
systems to handle traffic loads as they develop sufficient capacity should be provided so that
arriving elevators accommodate all waiting persons‖.

Edwards [4] reports on the benefits of MRL drives over other drives. This includes an
energy saving of up to 70% when compared to hydraulic drives. The MRL elevator utilizes
gearless traction which provides better performance and ride quality compared to hydraulic
elevators. MRL drive elevators also work at higher velocities, improving the perception of
ride quality over a conventional or hydraulic elevator. Data and telemetry obtained for
Hydraulic and MRL drives were compared for varying passenger capacity and tested for
speed, comfort, ride quality and power consumption.

11
 Figure 2.1: Hydraulic and Traction drive Configuration [4]

Asvestopoulos and Nickospyropolous [3] report that elevators equipped with gearless
permanent magnet synchronous motors are the more efficient type of elevator because of the
limited energy consumption during travel but have significantly higher power consumption
during standby.

The summarised investigation of energy efficiency of elevator is

 Doolaard reported on a comparison of the relative energy consumption of hydraulic

elevator, traction elevator and carried out energy measurements for these systems, during
a travel of 3 floors in both directions. Results were then normalized by dividing with the
mass of the car.
 Schroeder has developed a generalized equation to calculate the annual consumption of
energy of elevator per square meter of the building space. Use was made of eqn (1) to
calculate the daily consumption of energy, where R is the motor rating in Kilo Watts, SD
is the number of starts per day and T is a time factor expressed in seconds and dependent
type of drive and number of floors travelled.

 In the study, 33 elevators of different types were studied and analysed. This study
separated the drive consumption and the standby consumption of energy. The most
12
 important finding of this report was that standby consumption of elevator sometimes is the
80 % of the total consumption of energy. The percentage of standby consumption for a
type of elevator drive increases, as the daily usage gets lower. This was a matter of
concern in low residential buildings with low traffic conditions.

The methodology for energy measurements of elevator defines reference trip as follows:

1. Reference begins trip with open elevator door

2. Elevator doors are closed
3. Travel in a particular direction using the full height
4. Opening and closing of the elevator door
5. Travel in opposite direction using the full height

The measurement can be done either with empty car or with a particular load regime. For
measurements with empty car it is defined a load factor to introduce the effect of a
counterweight. Standby consumption was measured five minutes after end of trip. After
obtaining travel and standby demand, lifts were classified into an energy scale

Observations:

Table 2.2.1: Specification of measured life [5]

Lift Type Hydraulic Geared traction Traction

MRL

Nominal load in KG 375 300 630

Nominal speed in m/s .5 .6 1

Travel in m 3.47 12.16 3

Stops 2 4 2

Motor rating in KW 6 3.5 4.6

13
 Table 2.2.2: Overview of results [5]

Lift Type Hydraulic Geared Traction Traction MRL

Travel energy 18.5 24 9.7

consumption in W-hr

Standby 37 25 85
Consumption in W

Table 2.2.3: Results after normalization [5]

Lift Type Hydraulic Geared Traction Traction MRL

Specific energy 7.1 3.28 5.02

consumed W/Kgm

The results were summarised as follows:

 Traction elevators with counter weights consume less energy than conventional hydraulic
elevators during all travel.

 It is obvious from Table 2.3 that during travel a MRL elevator consumes less energy than
other types. The use of the permanent magnet technology in place of Gearbox leads to
reduced losses and increases the efficiency of MRL elevator.

 To attach balancing weight in hydraulic elevator can improve the energy efficiency of the
elevator.

 The high standby consumption has a large effect on the total consumption of energy of an
elevator, especially in low traffic applications.

14
 Though elevator systems utilize a very small fraction of the total energy consumption in a
building, the total energy consumption of the many millions of elevator is a matter of
significance. Energy efficiency of elevator is a major challenge for elevator industry.
Manufacturers are working on improving energy efficiency.

Celik [6] reports that MRL drives also have an edge in safety over other drives. However in
the event of seismic shocks MRL drives were found to perform worse than hydraulic or room
housed drives. Special care has to be taken for MRL drive since it is housed in the elevator
shaft and is subjected to a working environment full of dust, dirt, and moisture, a proper MRL
housing must be designed in lieu of a clean machine room.

Harvey [7] reports that an elevator consumes 5 % of total building electrical supply for a
low to medium rise building. Elevator consumption also includes consumption for HVAC,
lighting and other auxiliary services.

The methodology followed was:

1. Energy calculations based on first principle.

2. Direct measurement of energy use under varying conditions and parameters.
3. Simulations based on first principles, engineering data, and traffic models.

The results of the study were

 Elevators are engineered systems rather than manufactured products and are tailored or
designed to each installation. Reduction in elevator energy consumption if included as a
design parameter ensures that the elevator is designed for maximum efficiency.
 MRL drives with regenerative braking give the best performance, regenerative braking
converts energy dissipated as heat during braking back into the system as electric energy
and are more energy efficient.
 Using advanced control systems or software which utilize algorithms to carry out
proactive actions such as relocation of all elevators in a lobby to the ground floor in the
morning when maximum people enter the building can help save 5 % more energy in all
drive types.

15
 Lighting tax on energy can be reduced by using LED lighting and analog panels instead of
haptic panels, use of LED also reduces elevator cooling load by a small amount.
 Utilising various methods in conjunction can yield an energy saving of 30-35 % within
elevator classes.

Thus it becomes critically important to phase out less efficient drives for MRL or
hydraulic drives. The savings in power consumption alone justify the added cost of redesign
and the cost of MRL drive.

Andrew and Kaczmarczyk [8] report that the guiding system defines the datum of the
spatial relationship between the elevator and the building in which it operates, making sure
that the elevator cabin and counterweight follow a well defined accurate path through the
shaft way with required clearance with respect to equipment required for the elevator
operation (e.g. landing entrances). Because of its function in maintaining the cabin in a well
defined path, the guide rail system imposes forces, mainly lateral forces, on the elevator cabin
through the guide shoes. These forces will be relatively small in normal operation; however
the quality of the ride experienced by passengers is directly related to the quality of the
alignment and straightness of the guide rails. During safety gear operation, the forces due to
the deceleration of the cabin, and the support required after braking, are transmitted to the
foundation through the guide rails which are subjected to significant buckling forces.

Gibson [9] states that a guide rail mounted MRL causes an eccentric hauling of the cabin,
the cabin tilt caused by these load degrades ride quality and has to be constrained by the guide
shoes or rollers pressing on the rails. The guide rail now behaves as a beam supported by the
brackets and should have sufficient strength to safely carry these forces. Sufficient stiffness is
also required to maintain the front edge of the platform level with the landing as passengers
enter or leave the cabin. This forces the safety and stabilization component to act as a load
carrying component which is detrimental to overall operation of the elvator.

Thus the advantages of a hoistway spanning I beam as MRL support as opposed to a guide
rail spanning beam are
16
 Elimination of eccentric hauling and provision of superior positioning of MRL sheave

 Controller Cabinet may be located in shaft access way decreasing distance between
controller and drive

 Ease of inspection and maintenance increases, relative safety increases.

Santhakumar and Satiskumar [10] report that laterally stable steel beams can fail only by
flexure, shear, and bearing. The beams used in hoisting applications must be prevented from
shifting, assuming the local buckling of slender components does not occur. These three
conditions are the criteria for limit state design of steel beams. Steel beams would also
become unserviceable due to excessive deflection and this is classified as a limit state of
serviceability. The factored design moment, M at any section, in a beam due to external
actions should satisfy the following relation.

M ≤ Md

Where Md = design bending strength of the section

For members subjected to bending the beam buckling behaviour is represented as

Figure 2.2.1: Graphical representation of beam subjected to buckling [10]

17
 When the shear capacity of the beam is exceeded, the ‗shear failure‘ occurs by excessive
shear yielding of the gross area of the webs as shown, shear yielding is very rare in rolled
steel beam

Figure 2.2.2: Graphical representation of beam subjected to shear forces [10]

Zdenick [11] reports on the problem of lateral beam buckling of simply supported under
major axis bending perfect straight beams and beams with initial imperfections were
considered. Structural steel members can be classified as tension or compression members,
beams, beam-columns, torsion members or plates. The beams subjected to flexure typically
have strength and stiffness in the plane associated with bending about their major principal
axis (in the plane in which the loads are applied) much greater than in the plane associated
with bending about their minor principal axis. Unless these members are properly braced
against lateral deflection and twisting, they are subject to failure by lateral beam buckling
prior to the attainment of the full in-plane capacity. The aim was a stochastic analysis of
bending stability problem of simply supported hot-rolled I-beam with initial random
imperfections. Theoretical development and practical applications related to the uncertainty,
safety and reliability were obtained both in the field of civil engineering, and in multi-
disciplinary fields. The report concludes that thin-walled elements as beams, columns, trusses
or as sheeting rails extensively used in structural engineering, such as I-section members
typically exhibit a detrimental imperfection sensitivity, which drastically reduces their
ultimate load bearing capacity compared to their theoretical strength. The beam‘s
imperfections both geometrical and material can decrease its load carrying capacity.

18
 Stephen [12] states Macaulay‘s method is a preferred method of beam investigation within
many ‗mechanics of solids‘ modules. The method is, in essence, a first exposure to (and pre-
dates) generalized functions (e.g. Dirac delta, step, and ramp), with meaning given over to the
bracket notation, typically of the form [x − a] n; if the argument within the bracket is
negative, that is, if x < a, the term is ignored, while if positive, that is, if x > a, it is treated
normally. Such terms arise naturally when one calculates the internal bending moment within
a beam structure produced by uniformly distributed loading (UDL) when one has n = 2,
concentrated (or point) force loads when n = 1, and point moments when n = 0. Moreover, the
load is located (or commences in the case of a UDL) at x = a, leading to an obvious
mathematical structure. Having so derived an expression for the bending moment which,
using this notation, is valid at any location along the beam, the moment–curvature
relationship for the (small-slope) Euler–Bernoulli model is:

Where the positive or negative sign depends upon the sign convention employed. This
allows calculation of the transverse deflection, v(x), by integrating relatively simple functions
twice with respect to the axial coordinate, x. In practice, the integration is performed with
respect to the argument of the bracket, rather than x, in order to keep the bracket and its
meaning intact. The obtained is resolved so long as the constants are evaluated with the
meaning of the brackets taken into account as per W. H. Macaulay.

According to INSDAG [13] the elastic critical moment, MCR, is applicable only to a beam
of I section which is simply supported at ends. This case is considered as the basic case for
future discussion. In practical situations, support conditions, beam cross section, loading etc.
vary from the basic case. Deflection is calculated assuming a simply supported beam with no
consideration given to actual beam support lengths which are only taken into account in the
practical stage to check for beam failures. The following sections elaborating on these
assumptions and the necessary modifications to the basic case for design purposes are the
lateral restraint provided by the simply supported conditions assumed in the basic case is the
lowest and therefore MCR is also the lowest. It is possible, by other restraint conditions, to
obtain higher values of MCR, for the same structural section, which would result in better

19
utilization of the section and thus saving in weight of material. As lateral buckling involves
three kinds of deformations, namely lateral bending, twisting and warping, it is feasible to
think of various types of end conditions. But, the supports should either completely prevent or
offer no resistance to each type of deformation. Solutions for partial restraint conditions are
complicated. The effect of various support conditions is taken into account by way of a
parameter called effective length. The concept of effective length incorporates the various
types of support conditions. For the beam with simply supported end conditions and no
intermediate lateral restraint, the effective length is equal to the actual length between the
supports. When a greater amount of lateral and torsional restraints is provided at supports, the
effective length is less than the actual length and alternatively, the length becomes more when
there is less restraint. The effective length factor would indirectly account for the increased
lateral and torsional rigidities provided by the restraints.

Web bearing illustrates how concentrated loads are transmitted through the flange/web
connection in the span, and at supports when the distance to the end of the member from the
end of the stiff bearing is zero. The bearing resistance is given by

Where b is the stiff bearing length.

n = 5 except at the end of a member and at the end of the member

where is the distance to the end of the member from the end of the stiff member.

k = (T + r) for rolled I- or H-sections T is the thickness of the flange t is the web thickness.

pyw is the design strength of the web.

Web buckling, provided the distance from the concentrated load or reaction to the
nearer end of the member is at least 0.7d, and if the flange through which the load or reaction
is applied is effectively restrained against both rotations relative to the web lateral movement
relative to the other flange the buckling resistance of an unstiffened web. If the flange is not

20
restrained against rotation and/or lateral movement the buckling resistance of the web is
reduced to Pxr, given by

Where is the effective length of the web.

If it is found that the web fails in buckling or bearing, it is not always necessary to select
another section; larger supports can be designed, or load carrying stiffeners can be locally
welded between the flanges and the web. Stiffeners are checked for buckling and bearing in
accordance to structural design practices.

Majumder and Kaushik [14] studied the maximum deflection and stress analysis of a
simply supported beam under different types of loading. The theoretical calculations were
done by using the general Euler-Bernoulli‘s beam equation. The computational analysis was
done on Ansys software. Comparing the numerical results to those obtained from Ansys,
showed excellent accuracy of the theoretical calculations. It was noted that in case of
deflection the element type TET 8 Node element gave a closer value in all types of loading
than the element type BRICK 8 Node element. This inference is exactly opposite in case of
stress analysis.

Results were summarised as below:

Table 2.3.1: Comparison of Deflection (ANSYS and Theoretical) [14]

Deflection(m)
Element 1 Element 2 Analytical Error with Error with
results E1 (%) E2(%)
Single load 5.5E-04 5.91E-04 6.25E-04 11.1952 5.4288
UDL 0.033463 0.038436 0.0390625 14.3347 1.6038
UVL 3.79E-04 3.87E-04 0.0003912 3.2157 1.0353

21
 Table 2.3.2.Stress [14]
Stress (N/m2)
Element Element 2 Analytical Error with Error with
1 Results E1(%) E2(%)
Single load 71.8649 53.7781 75 4.18 28.30
UDL 3939.505 3202.64 3750 5.05 14.60
UVL 37.922 45.287 38.4 1.25 17.94

Kenji and Nobuoki [15] suggest the use of a Hall inspection panel. A hall-inspection panel
if built into the hall call button panel on the top floor, so that the elevator can be operated
without entering the elevator shaft during maintenance inspections and in times of emergency.
In addition to indicators showing the elevator stage, the hall-inspection panel includes an
operating switch for use in maintenance and inspections, an emergency rescue operation
switch, an emergency stopping device, and other devices and functions to ensure the
operation of safety mechanisms. The hall-inspection panel is installed within a box behind the
hall call button panel on the top floor so as not to compromise the aesthetics of the hall.

Ammar [16] studied the feasibility of introduction of Total Quality Management (TQM) to
existing Quality Control and Inspection processes. The author states that QC is an
implementation of Plan Do Check Act (PDCA) cycle where planning step starts with
existence or acknowledgement of a problem, the outcome of this determines objectives of
performing quality control and steps are designed to implement these objectives. The Do step
is actual conduction of control plan. The Check step involves evaluating actual performance
and measuring these against set objectives.

Practically quality control is responsible for transforming daily routine work; ultimately
quality control aims at achieving product quality and customer satisfaction. Quality control
works best when conducted as a series of processes carried out using PDCA cycle
continuously. The tools required to carry out such an approach are Statistical Process control
22
(SPC), Root Cause Analysis (RCA) and feedback loops. Organizations have to strive for
implementing best possible inspection and control practices economically and efficiently.

Ishikawa [17] re affirms the importance of economy in inspection practices. Traditional

inspection approach was to carry out inspection at the end of manufacturing or assembly
process Ishikawa criticizes this approach as it does not promote and process improvement and
requires an average of 15 % inspectors to line workers. Citing inspection as being too little
too late too ineffective Ishikawa postulates problem prevention by carrying out root cause
analysis instead of depending on inspection alone to fix errors before they are committed
again.

Figure 2.3: Ishikawa Quality assurance planning[17]

Clifford [18] states in order to implement an effective QC program, the company decides
which specific standards the product or service must meet. Then the extent of QC actions
must be determined .Real-world data may be collected and the results and corrective action
decided upon and. If too many unit failures or instances of poor service occur, a plan must be
devised to improve the production or service process and then that plan must be put into
action. Finally, the QC process must be ongoing to ensure that remedial efforts, if required,
have produced satisfactory results and to immediately detect recurrences or new instances of

23
trouble. A well‐structured Designer Quality Control Plan helps to ensure that designs are
economical, constructible, maintainable and appropriate for their locations and surroundings.

The methodology suggested is

1. Inculcate good design principles.

2. Identify design inadequacies.

3. Cost analysis/Value engineering.

Design Principles are

 Economy of functions

Economy of functions is balancing of the number of functions performed by a particular

component against the quality or effectiveness with which it performs all the functions. The
MRL drive if mounted on a guide rail mounted beam which transmits forces to the pit floor
by means of the guide rails forces the guide rails to function not just as stabilization and
safety equipment but also as a load carrying member for the hoisting support. Moving the
MRL drive to a hoistway mounted beam not only frees up one function of guide rails but also
ensures effectiveness of beam as a hoisting support is maximised by distributing the load at
four points two on each beam of the pairing.

 Force balance and transmission

The basic objective of this design principle is to ensure that all forces (torsional, shear and
bending) are transmitted in straight lines. This is obtained by offset loading in which the load
as to be as close to beam constraints as possible ( ideal case is load applied at support point).
The load points are closer to supports in Hoist way mounted beam than in an equivalent MRL
mounted beam. Force balancing ensures design is such that large bending end thrusts and
imbalances are eliminated.

 Strength

This design principle ensures most economical use of material (therefore dimensions and
weight) while still ensuring fulfilment of design duty.
24
 Limiting irregularities and deformations

Chew [19] reports in spite of regular and stringent inspections according to elevator
maintenance checklists defects are prevalent. From analysis, a defect was observed to have
adverse effect on (1) economy, (2) system performance; and (3) safety & comfort. These
factors contribute to the level of seriousness of a defect and were considered to establish the
significance of a defect. A frequent defect might have insignificant effect, while a very
serious defect may occur rarely. For example, closing of car door while user are getting in and
out of the car is common but the force exerted causes only nudging effect, while false opening
of a lobby door when there was no elevator car is rare but can cause fatal fall through
hoistway.

The three major impacts were defined as:

● Economic loss: considerable financial losses sustained due to of the defect.

● System performance loss: the system performs significantly below normal operating
efficiency due to the defect, e.g. repeated opening and closing of car door.

● Safety & comfort loss: affected safety of the users and maintenance employees due to the
defect.

It was established that among the defects in vertical transport system, most of the defects
can be prevented by considering three major maintainability criteria, namely, design and
specification, construction or installation, and inspection and maintenance (I and M). It was
found that among 28 significant defects, 12 were design related, 10 were due to faulty
installation or poor construction quality and inadequate I and M practises were responsible for
19 defects. The maintenance quality was largely subjective with regard to cleanliness and
lubrication it was established that the most important contributing factors for maintainability
is good maintenance, followed by good design and material specification, followed by
workmanship during construction or installation. This report highlights the importance of
maintenance and inspection for MRL drives. New configurations of MRL drive which house
it on a hoist-way spanning structure at top or bottom of shaft make inspection and
maintenance easy and reduce costs, thereby reducing costs over the elevators lifetime.
25
 Chapter 3

Design of MRL Drive Support

3.1 Procedure

 The dimensions of elevator shaft and cabin were decided based on passenger capacities
(standard elevator capacities range from 4 to 12 passengers in increments of two).
IS 14665 Part 1 Section 1 was used in the determination passenger load for different
no of passengers.
Dimensions have been taken from this standard for various passenger loads.
 The dimensions of beam required for new hoisting configuration were determined and
beam was checked for failure.
 Effect of plate stiffeners on beam deflection was analysed for the two most deflected
beams.
 Guide rails were checked for satisfactory operation even though their design remains
constant. Impact of new configuration on elevator quality control and inspection was

26
analysed. The code of practice for installation and maintenance of passenger elevators was
provided by IS 14665 Part 2 Section 1 .

The safety rules that are required for operation of passenger elevators were provided by IS
14665 Part 3 Section 1.

3.2 Design of I Beams

MRL Guda drives are utilized by the company for elevators of capacity 8 and 10
passengers for buildings in which travel is limited to 20 storey. The drive is mounted on an I
beam which spans the guide rail and is secured to them with angles with adequate clearance
from top roof as per IS 14665.

The forces are transmitted by the guide rail to the pit floor. In the proposed design the
drive is mounted on twin I beams secured to hoist shaft by angles with adequate clearance
from top roof as per IS 14665 the civil work involved changes from building to building as
per client requirement and working conditions. Mounting is carried out by means of four
isolation pads, two on each beam and inspection is carried out before assembling other
components.

At ESCON Elevators it was proposed that the same ISMB 300 beam size which was used
in guide rail mounted support be used in a longer span for hoist way spanning beam. However
two I beams are to be used in this configuration hence use of beams of a lower size could be
made.

The twin I beams have to be designed for elevator capacities of 8 and 10 passengers and
checked for safely carrying the loads including impact loads. The guide rails are checked for
Buckling and failure. The supports are chosen by the civil contractor based on beam
dimensions and client requirement and checked for safe operation. Beam deflection is an
important parameter which affects elevator ride quality.

27
 Beam selection was carried out utilizing IS 800 resource and Design was verified
according to ISI Structural Engineers Handbook IS SP 2.

3.2.1 Design of beam for 8 passenger elevator

Principle dimensions

Hoistway span = 2.1 metres

Number of passengers

N=8

Passenger load

P= 544 kg

Cabin load

Q= 1.25 * 544 = 680 kg

To ensure turning effort is reduced for every possible loading of elevator car the counter
weight load is calculated as

Counter Weight

C.W =0.5*Passenger load + cabin load= 952 kg

Total load

T = 952 + 544 +680 = 2176kg

Considering impact and design factor of 1.6

Final Load

W = 2176*1.6= 3620 kg

28
Load is distributed at 4 points by means of mounting pads,2 on each beam therefore load at
each point

Figure 3.1: Beam loads and reactions

Reaction forces were calculated by considering equilisbrium of forces i.e ƩFx and ƩFy = 0.

= 7.69 kN

= 10.06 kN

Where and are reaction forces at supports.

Beam deflection was calculated using McCauley‘s formula.

x a | | (1)

Where

a and b are the progressive distances of the forces from the support.

y is deflection of beam

x is distance from the fixed end

29
Mx is Maximum bending moment

E is Young‘s modulus

I is Moment of inertia

From Machine specifications and Mounting positions we have

a =0.75 m , b =0.88 m

From properties of Structural Steel

E= 2.15*105N/m2

P1= P2 = 905kg

Integrating equation (1) and substituting boundary conditions

Boundary conditions:-

At the supports deflection of beam is zero

At x = 0, y= 0

on solving integration constant c2 = 0

At x =2.1m, y = 0

on solving we get c1 = -3.4766

To find point of maximum deflection the slope is equated to zero

i.e. = 0.

Solving we get max deflection at x = 1.0511 m.

Solving for maximum allowed deflection of 2.1 mm, we select ISMB150 beam having
moment of inertia 726.4 cm4 from IS 800

30
Solving for maximum deflection at x = 1.0511m

We get maximum deflection y = 1.26mm.

As per IS SP.2.1962 small deflections below (1/325) of unsupported span do not affect design

Hence the beam is acceptable.

Checking for beam bearing

The bearing resistance is given by

Where

b is the stiff bearing length

n = 5 except at the end of a member

k = (T + r)

pyw is the design strength of the web

Web bearing is obtained as 76.67 kN which is adequate

Bending stress calculation

Bending stress for beams was calculated by

σb =

Mb=maximum bending moment

Z=Section modulus

Maximum bending moment

Mb = Force × Displacement

Mb =5.771×106 N.mm

31
Section modulus for I beams is given by

–
Z=

= 9.533×106 mm2

Where

b is flange width

h is depth of section

Therefore the bending stress =5.771×106 /9.533×106

σb =60.5 N/mm2

3.2.2 Design of beam for 10 passenger elevator

Principle dimensions are

Hoistway span = 2.3 metres

Number of passengers

N = 10

Passenger load

P = 680

Cabin load

Q = 1.25 * 680 = 850 kg

To ensure turning effort is reduced for every possible loading of elevator car the counter
weight load is calculated as

Counter Weight

C.W =0.5*Passenger load + cabin load= 1190 kg

32
Total load

T = 680 + 850 + 1190 = 2720 kg

Considering impact and design factor of 1.6

Final Load

W = 2720*1.6= 4352 kg

Load is distributed at 4 points by means of mounting pads,2 on each beam therefore load at
each point

P= = 1088 kg

Figure 3.2: Beam loads and reactions

Reaction forces were calculated by considering equilibrium of forces i.e. ƩFx and ƩFy = 0.

= 10.42 kN

= 11.15 kN

Where and are reaction forces at supports.

33
Beam deflection was calculated using McCauley‘s formula.

x a | | (1)

Where

a and b are the progressive distances of the forces from the support.

y is deflection of beam

x is distance from the fixed end

Mx is Maximum bending moment

E is Young‘s modulus

I is Moment of inertia

From Machine specifications and Mounting positions we have

a =0.784 m, b= 0.81 m

From properties of Structural Steel

E= 2.15*105N/m2

P1= P2 = 1088 kg

Integrating equation (1) and substituting boundary conditions

Boundary conditions:-

At the supports deflection of beam is zero

At x= 0, y= 0

on solving integration constant c2 = 0

At x= 2.3 m, y= 0
34
on solving we get c1 = -6.15

To find point of maximum deflection the slope is equated to zero

i.e. = 0.

Solving we get max deflection at x = 1.156m.

Solving for maximum allowed deflection of 2.3 mm, we select ISMB175 beam having
moment of inertia 1272 cm4 from IS 800

Solving for maximum deflection at x = 1.156m

We get maximum deflection y = 1.232mm.

As per IS SP.2.1962 small deflection below (1/325) of unsupported span does not affect
design

Hence the beam is acceptable.

Checking for beam bearing

The bearing resistance is given by

Where

b is the stiff bearing length

n = 5 except at the end of a member

k = (T + r)

pyw is the design strength of the web

Web bearing is obtained as 110.14 kN which is adequate

Bending stress calculation

35
Bending stress for beams was calculated by

σb =

Mb=maximum bending moment

Z=Section modulus

Maximum bending moment

Mb = Force × Displacement

Mb =8.169×106 N.mm

Section modulus for I beams is given by

–
Z=

Z = 1.4315×105 mm2

Where

b is flange width

h is depth of section

Therefore the bending stress =8.169×106 /1.4315×105

σb =57.06 N/mm2

3.2.3 Design of beam for 8 passenger elevator

Selecting alternate configuration of cabin with deeper cabin to test for beam deflection

Principle dimensions are

Hoistway span = 2.2 metres

Number of passengers

N=8

Passenger load

36
P= 544 kg

Cabin load

Q= 1.25 * 544 = 680 kg

To ensure turning effort is reduced for every possible loading of elevator car the counter
weight load is calculated as

Counter Weight

C.W =0.5*Passenger load + cabin load= 952 kg

Total load

T = 952 + 544 +680 = 2176kg

Considering impact and design factor of 1.6

Final Load

W = 2176*1.6= 3620 kg

Load is distributed at 4 points by means of mounting pads,2 on each beam therefore load at
each point

P= = 905 kg

37
 Figure 3.3: Beam loads and reactions

Reaction forces were calculated by considering equilibrium of forces i.e. ƩFx and ƩFy = 0.

= 9.69 kN

= 8.062 kN

Where and are reaction forces at supports.

Beam deflection was calculated using McCauley‘s formula.

x a | | (1)

Where

a and b are the progressive distances of the forces from the support.

y is deflection of beam

x is distance from the fixed end

Mx is Maximum bending moment

E is Young‘s modulus

I is Moment of inertia
38
From Machine specifications and Mounting positions we have

a =0.776 m, b= 0.85 m

From properties of Structural Steel

E= 2.15*105N/m2

P1= P2 = 905kg

Integrating equation (1) and substituting boundary conditions

Boundary conditions:-

At the supports deflection of beam is zero

At x= 0, y= 0

on solving integration constant c2 = 0

At x= 2.2m, y= 0

on solving we get c1 = -4.22

To find point of maximum deflection the slope is equated to zero

i.e. = 0.

Solving we get max deflection at x = 1.103m.

Solving for maximum allowed deflection of 2.2 mm, we select ISMB175 beam having
moment of inertia 1272 cm4 from IS 800

Solving for maximum deflection at x = 1.103m

We get maximum deflection y = 0.901mm.

As per IS SP.2.1962 small deflections below (1/325) of unsupported span do not affect design

39
Hence the beam is acceptable.

Checking for beam bearing

The bearing resistance is given by

Where

b is the stiff bearing length

n = 5 except at the end of a member

k = (T + r)

pyw is the design strength of the web

Web bearing is obtained as 76.67 kN which is adequate

Bending stress calculation

Bending stress for beams was calculated by

σb =

Mb=Maximum Bending Moment

Z=Section Modulus

Maximum bending moment = Force × Displacement

Mb =7.519×106 N.mm

Section modulus for I beams is given by

–
Z=

Z = 9.533×106 mm2

Where

b is flange width
40
h is depth of section

Therefore the bending stress =7.519×106 /9.533×106 mm2

σb =52.52 N/mm

3.2.4 Design of beam for 10 passenger elevator

Selecting alternate configuration of cabin with deeper cabin to test for beam deflection

Principle dimensions are

Hoistway span = 2.2 metres

Number of passengers

N = 10

Passenger load

P= 680 kg

Cabin load

Q= 1.25 * 680 = 850 kg

To ensure turning effort is reduced for every possible loading of elevator car the counter
weight load is calculated as

Counter Weight

C.W =0.5*Passenger load + cabin load= 1190 kg

Total load

T = 680 + 850 + 1190 = 2720 kg

Considering impact and design factor of 1.6

Final Load

41
W = 2720*1.6= 4352 kg

Load is distributed at 4 points by means of mounting pads,2 on each beam therefore load at
each point

P= = 1088 kg

Figure 3.4: Beam loads and reactions

Reaction forces were calculated by considering equilibrium of forces i.e. ƩFx and ƩFy = 0.

= 9.14 kN

= 12.43 kN

Where and are reaction forces at supports.

Beam deflection was calculated using McCauley‘s formula.

x a | | (1)

42
Where

a and b are the progressive distances of the forces from the support.

y is deflection of beam

x is distance from the fixed end

Mx is Maximum bending moment

E is Young‘s modulus

I is Moment of inertia

From Machine specifications and Mounting positions we have

a =0.87 m, b= 0.91 m

From properties of Structural Steel

E= 2.15*105N/m2

P1= P2 = 1088 kg

Integrating equation (1) and substituting boundary conditions

Boundary conditions:-

At the supports deflection of beam is zero

At x= 0, y= 0

on solving integration constant c2 = 0

At x= 2.2 m, y= 0

on solving we get c1= -3.076

To find point of maximum deflection the slope is equated to zero

43
i.e. = 0.

Solving we get max deflection at x = 1.119m.

Solving for maximum allowed deflection of 2.2 mm, we select ISMB175 beam having
moment of inertia 1272 cm4 from IS 800

Solving for maximum deflection at x = 1.119m

We get maximum deflection y = 1.123mm.

As per IS SP.2.1962 small deflections below (1/325) of unsupported span do not affect design

Hence the beam is acceptable.

Checking for beam bearing

The bearing resistance is given by

Where

b is the stiff bearing length

n = 5 except at the end of a member

k = (T + r)

pyw is the design strength of the web

Web bearing is obtained as 110.4 kN which is adequate

Bending stress calculation

Bending stress for beams was calculated by

σb =

Mb=Maximum Bending Moment

44
Z=Section Modulus

Maximum bending moment = Force × Displacement

Mb =7.951×106 N.mm

Section modulus for I beams is given by

Z = (bh3 – b‘h‘3)/6h

Z= 1.4315×105 mm2

Where

b is flange width

h is depth of section

Therefore the bending stress =7.951×106 /1.4315×105

σb =55.54 N/mm2

45
 Chapter 4

Structural Analysis of Beam in ANSYS

4.1 Introduction

The hoisting support consists of two twin I beams spanning the hoistway with the MRL
drive mounted on two points on each beam on isolation pads. I beam cross sections were
modeled as per IS 800 the dimensions of beam were obtained from design calculations. The
exact location of machine mounting points may vary according to drive chosen by customer.
For Guda gearless traction drives selected from company catalogue calculated loads were
applied at mounting points. Static analysis was carried out as the maximum loads imposed on
I beam are constant.

46
 Figure 4.1 Meshed model of I beam

4.2 Analysis of ISMB 150 beam for 8 passengers

Deformation analysis

Figure 4.2.1 Deformation Analysis

47
 The Figure 4.2.1 shows the deformation in ISMB 150 beam. From the figure it can be concluded
that maximum deformation takes place in the beam span between the load points (as predicted by
Macaulays theorem). The maximum value of deformation is 1.0962mm which is less than 1/325 times
unsupported span length as specified by IS SP and is acceptable.

Stress analysis

Figure 4.2.2 Stress Analysis

The above figure shows the stress in ISMB 150 beam. From the figure it can be concluded that the
maximum value of stress is 41.2 MPa which is less than as specified by IS SP and is acceptable.

48
4.3 Analysis for ISMB 175 beam for 10 passengers

Deformation analysis

Figure 4.3.1 Deformation Analysis

The above figure shows the deformation in ISMB 175 beam. From the figure it can be concluded that
maximum deformation takes place in the beam span between the load points (as predicted by
Macaulays theorem). The maximum value of deformation is 1.0193 mm which is less than 1/325 times
unsupported span length as specified by IS SP and is acceptable.

49
Stress analysis

Figure 4.3.2 Stress Analysis

The above figure shows the stress in ISMB 175 beam. From the figure it can be concluded
that the maximum value of stress is 26.7 MPa which is less than as specified by IS SP and is
acceptable.

50
4.4 Analysis of ISMB 175 beam for 8 Passengers Wide Cab

Deformation analysis

Figure 4.4.1 Deformation Analysis

The above figure shows the deformation in ISMB 175 beam. From the figure it can be concluded
that maximum deformation takes place in the beam span between the load points (as predicted by
Macaulays theorem). The maximum value of deformation is 0.74119 mm which is less than 1/325
times unsupported span length as specified by IS SP and is acceptable. Deep cab configuration causes
less deflection of I beam as suggested by calculations.

51
Stress analysis

Figure 4.4.2 Stress Analysis

The above figure shows the stress in ISMB 175 beam. From the figure it can be concluded
that the maximum value of stress is 20.33 MPa which is less than as specified by IS SP and is
acceptable.

52
4.5 ISMB 175 beam for 10 passengers wide cab

Deformation analysis

Figure 4.5.1 Deformation Analysis

The above figure shows the deformation in ISMB 175 beam. From the figure it can be concluded
that maximum deformation takes place in the beam span between the load points (as predicted by
Macaulays theorem). The maximum value of deformation is 0.90307 mm which is less than 1/325
times unsupported span length as specified by IS SP and is acceptable. Deep cab configuration causes
less deflection of I beam as suggested by calculations.

53
Stress analysis

Figure 4.5.2 Stress Analysis

The above figure shows the stress in ISMB 175 beam. From the figure it can be concluded
that the maximum value of stress is 26.74 MPa which is less than as specified by IS SP and is
acceptable.

4.6 Addition of stiffeners

INSDAG [13] recommends the use of stiffeners be made to provide stiffer beams with less
deflection. Stiffeners are designed as per IS SP. Use of stiffeners is not necessary as beam
deflection is well within limit but beam deflection is an important parameter for determination
of Elevator ride quality.

54
4.6.1 Design

As per IS SP 1962 transverse stiffeners are utilized to prevent local web buckling.
INSDAG [13] suggests use of Stiffeners provided at bearing ends and load bearing
intermediate stiffness to prevent load induced local web buckling and bearing failure. For
calculation of stiffener dimensions for ISMB 150 beam.

Web bearing resistance of beam is calculated as

= (10 + 24.4)*4.8*275

For Stiffener at support A

Reaction at support is 7.69 kN

Let Bearing stiffener of thickness tb be used

Let width be 40 mm to avoid exceeding outstand [22]

Area of stiffener

As = 40*2*tb

As = 80tb

Stiffener bearing capacity

Ps = As*

Ps = 22000 tb

Ps = 22*tb kN

To prevent stiffener bearing failure

Thus tb= 1.6904

Choosing stiffener of thickness 5mm

55
Checking for buckling

I is moment of inertia

Ab= ‗770mm2

Length of stiffener

d = 150 + 2*1.6

d = 134.8mm

( )

rxx= 18.18mm

Buckling load is obtained as

Pxy= 21.1kN

Which Capable of resisting buckling load which is 7.69 kN

For stiffener at support B

Web buckling resistance

Pbw= 44.88kN

As = 80tb

Vb = 10.06kN

tb= 5mm adequate in bearing

Check for buckling

Pxy= 275*1217.6

Pxy= 33.84kN; Thus the design is adequate to carry load.

56
4.6.3 Structural Analysis of stiffened beam in ANSYS

For ISMB 150 beam

Deformation analysis

Figure 4.6.3a Deformation Analysis

From the picture it can be seen that addition of stiffeners at strategic points as per IS SP
[21] and Tata steel [22] decreases the deflection of beam and reduces chances of local web
buckling taking place at supports and load points.

57
Stress Analysiss

Figure 4.6.3b Stress Analysis

As predicted by INSDAG [13] Stiffeners can be used to prevent load induced local web
buckling, as seen from this picture already infinitesimal risk of local web buckling is reduced
due to addition of transverse load bearing and bearing stiffeners

58
For ISMB 175 beam

Deformation analysis

Figure 4.6.3c Deformation Analysis

From the picture it can be seen that addition of stiffeners at strategic points as per IS SP
[21] and Tata steel [22] decreases the deflection of beam and reduces chances of local web
buckling taking place at supports and load points.

59
Stress analysis

Figure 4.6.3d Stress Analysis

As predicted by INSDAG [13] Stiffeners can be used to prevent load induced local web
buckling, as seen from this picture already infinitesimal risk of local web buckling is reduced
due to addition of transverse load bearing and bearing stiffeners

60
 Chapter 5

Quality Control

5.1 Introduction

Inspection quality control for hoisting support (I beams) is divided into three phases

 Pre installation Inspection

Beams are inspected for dimensions and grade (verified by manufacturer‘s embossed
data), straightness of flanges and for any defects such as cracks, deep scratches and non
conformance reports (NCR) are created.

 Post installation inspection

Beams are inspected for damage during transport to site, damages incurred during
erection hauling. Non conformance reports (NCR) are generated for any deviances.

61
 Routine operational inspection

Maintenance and inspection during operational life span are carried out as per IS: 4591.

5.2 Procedure

• The company process control approach was studied to check for adherence to PDCA
quality control iterative cycle and TQM principles..

• PDCA cycle [Plan Do Check Act] forms the basis of a cost effective and efficient quality
control process while Total Quality Management is a methodology derived of quality
control which looks to customers to define quality. TQM strives to implement operational
and inspection quality control.

• In the literature utilized mean ratings for determining the level of seriousness of the
defects were calculated from the feedback received. Mean rating for frequency was
defined as , while the same for impacts on four aspects, namely, economy, system
performance, and safety & comfort were denoted by , and respectively .

For each defect, the mean rating was calculated by a general formula

∑
Mean frequency of occurrence ∑

Where

I is frequency rating.

is number of responses for rating.

62
5.3 Observations:

Table 5.1: Significance of defects in machine room

Sub Defects In machine room XFR XEC XSP XSC

Component

Controller Lift jam (stalled car) 2.62 3.10 3.15

Uncomfortable motion / jerky 2.29 2.80 3.15

landing

Long waiting time (>30sec) 2.28

Vibration during travel due to

governor
Governor 2.90
rope worn/ uneven tension/ not
Machine strong

Intermittent fault difficult to 2.65

detect

Poor workmanship. E.g. Brake

rod not
2.51
secured to plate / uneven

Mishandling. E.g. under / over

lubrication
3.08

63
Other defects (30 no)

Machine Room

Dirty with rubbish, carbon dust, insufficient lubricant, insufficient lighting (<200 lux atfloor
level).water seepage through wall / ceiling, overheated (>38°C) machines in stuffy room,
inadequate clearance around machines & control panel.

Controller

Transformer noisy / dirty; Inverter cooling fan dirty / dusty, intermittent faults/ fire from
overused/ burnt resistor, noisy bearing, dirty machine with leaking cover/ oil seal.

Traction machine

Oil level is too low or high, oil level gauge blurred / faulty, faulty brake, noise and vibration
by worn out, dry secondary sheave bearing/ groove, machine bed isolation rubber worn, main
rope worn, carbon brush holder loose/ damaged.

Traction motor

Bearing noisy, overheated motor, cooling fan dirty / noisy.

Brake assembly

Vibration and jerky emergency stops, brake drum scratched, burnt lining , incorrect clearance
of plunger stroke, brake rod is not secured to plate Brake lever uneven, brake slips
excessively for emergency stop, brake shaft collar clearance out/ screw loose ,levers jammed/
slippery.

Governor Machine

Noisy operation, oily / dirty machine, faulty design. E.g. less clearance, long waiting

64
5.4 Results

For four sub-components of hoistway, a total of 13 common defects were identified from
the, among which most were found to be dependent on the MRL drive. Careless maintenance
is not only responsible for oil spillage during lubrication but also for wrong size of roller shoe
causing excessive noise and vibration in guide rail during lift degrading ride quality. Though
elevators are manufactured under stringent ISO certification, site conditions are often hostile
and frequent inspection of the sensitive MRL drive and subsidiary components is required.
Mounting MRL drive in suggested configuration allows inspection to be carried out more
efficiently by increasing ease of access and with the use of a hall inspection panel can be
carried out without extensive blockading of hoistway.

It is in agreement with the general understanding that quality control at site is not as strict
as of factory. As a result the systems performance is highly affected since commissioning
incurring higher maintenance cost. Maintenance costs can be reduced by improving ease of
access to MRL drive through alternate configuration. From the present study, it was
established that among many defects in vertical transport system, most of the defects can be
prevented by routine inspection & maintenance (I&M) of the MRL drive and subsidiary
components.

Hoistway spanning beam configuration for MRL drives thus provides a better ride quality
by eliminating eccentric hauling and further, this may provide a simple means to lower life
cycle maintenance cost of building services by improving ease of access to part for inspection
and maintenance purposes.

65
 Chapter 6

Conclusion

 Machine Room Less (MRL) drives were proved

 to be superior to conventional elevator drives in terms of operation and efficiency
however conventional elevator drives housed in machine rooms are deemed to have safer
and easier inspection.
 An alternate configuration to existing guide rail mounted MRL support was envisioned
which provided the operational superiority of MRL drive with the ease of access of
conventional drive with same space savings as a regular MRL drive
 The company ESCON Elevators proposed the use of same 300 ISMB I beams for
alternate configuration as were used in pre existing configuration regardless of passenger
capacity
 Use of ISMB 150 and ISMB 175 beams (Depending on passenger capacity) was proved
possible by theoretical calculations and calculations were verified by ANSYS analysis
with an error of up to 13.1 % for smallest beam.

66
 Inspection of MRL drive and subsidiary components is made easier and safer by hoist way
spanning twin beam configuration leading to more economic quality control and lower
elevator costs over its lifetime
 High costs of maintenance and inspection caused by higher time consumption due to
location of MRL drive in a difficult to access configuration are a major disadvantage of
MRL drives. The new configuration eliminates this disadvantage

67
 Chapter 7

Future Scope

 The design flexibility offered by MRL drives to elevator designers is yet to be taken full
advantage of. The full potential of MRL drives maybe utilised by housing the drive in
elevator pit along with control cabinet integral in the shaft
 This configuration would make of two separate hoisting supports for drive itself and the
beam supporting cabin and counterweight loads
 High costs of maintenance and inspection caused by higher time consumption due to
location of MRL drive in a difficult to access configuration are a major disadvantage of
MRL drives. The inspection of MRL drive would be easiest in this configuration.
 However due to longer roping, rope vibration may degrade ride quality. Means to improve
ride quality would have to be investigated.

68
 APPENDIX

Appendix A

Fig: IS standard for passenger weight.

69
Appendix B

Fig: IS standard for I-beam sizes.

70
Appendix C

Project Manuscript

A review on Machine Room Less (MRL)

Elevators

Akshay Pai
Student, Department of Mechanical Engineering
SIES Graduate School of Technology, Mumbai, Maharashtra, India
akshayvpai@gmail.com

Rohit Nair
Student, Department of Mechanical Engineering
SIES Graduate School of Technology, Mumbai, Maharashtra, India

nair.rohit@siesgst.ac.in

Philips George
Student, Department of Mechanical Engineering
SIES Graduate School of Technology, Mumbai, Maharashtra, India

Abstract- Machine Room Less (MRL) elevator drives offer advantages over conventional traction drives such as a
higher energy efficiency, low weight, and more design freedom and better utilization of hoist-way space. MRL drives have
emerged as the superior choice in most high rise applications. Currently a majority of MRL drives are mounted on a guide
rail spanning beam which forces safety and stabilization components to act as load bearing component and degrades ride
quality. The MRL drives are also difficult and costly to inspect and maintain if located in such a configuration. Alternate
methods of mounting MRL drives on hoist-way spanning I beams if utilized can eliminate eccentric hauling leading to
better utilization of guide rails and an improved ride quality. A hoist-way spanning support configuration also aids in
decreasing inspection and maintenance costs by improving ease of access and increasing safety. Thus a properly located
MRL drive can provide best possible operating parameters for a high rise application with lower costs of inspection and
maintenance over the elevator lifetime.

Keywords –Elevator, MRL, Beam, Inspection, Lift, Design

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 I. Introduction

Elevators are Vertical transport systems that are utilized for efficient transport of passengers
and goods between different efficient transport of passengers and goods between different
floors (landings). An elevator differs from other hoisting mechanisms in that it runs at least
partially on guide rails. The elevator is a mass transit system (conveyor) whose design has
evolved rapidly from that of a simple drum and rope traction system to traction less and
machine room less systems. Elevator usage has grown exponentially in India but the adoption
of newer technologies such as the MRL drive or Hydraulic drive systems is lagging behind
because of additional costs of maintenance and inspection involved as convenience of
machine room diminishes. It becomes imperative to establish MRL elevators as a superior
choice and provide additional future changes that provide advantage of MRL drive during
operation and the convenience of a machine room during inspection and maintenance. Such
an elevator drive will provide least cost of maintenance and inspection for the customer over
the elevator lifetime.

II. Literature review

A. Present advantages of MRL drives

Celik F. [1] reports that Hydraulic elevators are more suited to small rise buildings and freight applications. This
report after experimentally mapping the performance of different elevator drives under varying parameters of
passenger capacity, severity of service, travel and speed finds that hydraulic elevators have advantages over
traction drives in low rise applications

 Substantially lower initial cost of equipment and its maintenance for a given capacity hydraulic elevator
equipment cost up to 40 % less than traction equipment
 More building space utilization as the hydraulic elevator utilises up to 12 % less space than an equivalent
traction elevator, as the hydraulic system imposes no load on the column the column size can be reduced
 Effective for high load requirements such as freight elevators
 Lowest cost down speed amongst all elevators as gravity is utilized as the motive force.

However Hydraulic elevators have deficiencies and disadvantages in areas that MRL drives excel in. Hydraulic
elevators have only proven to have an advantage over MRL drives in low speed, low rise high capacity
applications.

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The report concludes that MRL drives despite their superiority in high rise applications have costly and difficult
maintenance regimes because the machine is located in the top of the hoist-way or, on or under the cab, reaching
it can be difficult. Accidents during construction and servicing of the elevator are more likely. In case the car is
stuck, the machine cannot be serviced from the top of the car, other methods may need to be attempted. The
performance of Hydraulic, Conventional Traction and MRL (Machine Room Less) drives were studied for
varying conditions of speed, travel, capacity and severity of service and states that among Hydraulic elevators
,and traction drives, Hydraulic elevators impose the least load on the hoist-way and have least cost of
construction and operation however due to their slow nature and requirement of environmental clearance to dig
oil wells they are only utilised in low rise buildings and other applications where Hydraulic elevators prove
advantageous and traction drives cannot be used. Between conventional traction and MRL drives, MRLs give
better ride quality more efficient performance, better product life and higher speeds than a similar conventional
drive however a conventional drive imposes load only on the building structure where as an MRL exerts load on
the hoisting support and MRL hoisting support has to be designed accordingly. Though having a higher initial
cost MRL systems are more suitable for use than conventional system. F Celik concludes by stating that in the
near future elevator market will be dominated by MRL and hydraulic drives sharing a majority of the market
share

In the following table, hydraulic and MRL drive elevators are compared with each other with respect to various
design constraints in low rise buildings. Total assessment mark of 3 is divided among the two elevator systems
for each and every design constraint and the percentage marks for safety, cost, other and total points are shown
in a graph. The points awarded for different conditions may vary for among assessors but the general trend is
very unlikely

Table 1: Summarization of results in [1]

Safety Advantage Hydraulic MRL

Installation and maintenance Driving equipment is safer easier Drive assembled in the shaft, passers
and quicker by exposed to danger

Relative safety 89% safe Safety 11%

Cost Advantage Hydraulic MRL

Equipment Cost is least among all types MRL costs are 30 % higher

Installation Installation costs are lower Installation costs are higher by 25 %

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 Maintenance Costs are moderate Subjected to degrading working
environment and replacement is
expensive

Energy Energy costs are higher than MRL can be 80% more energy
MRL drives efficient

Relative savings 63 % savings 37% savings

Other advantages Hydraulic MRL

Noise Noise is dampened Noise is present due to presence of

MRL in hoist-way

Speed Only suitable for low speeds Suitable for high speed applications

Ride comfort Similar to that of MRL Similar to that of hydraulic

Car space Larger car can fit in same space Car size is limited by counterweight

Relative advantages Other advantages 53% Other advantages 47%

Total Relative advantages and 65 % 35 %

value

Tetlow K. [2] states that apart from their advantages in performance over conventional drives, MRL drives also
offer many design advantages.MRL drives provide major space savings which is especially important in high
rise buildings. The drive can be mounted on overhead beams or on deflector beams.MRL increases the design
freedom for architects and engineers, however MRL has several design considerations which differ from those
for conventional drives. Interior cab design is governed by limitations on cab weight because MRL machines are
smaller than traditional traction models; permissible cab weight is less than with traditional traction machines.
Different MRL drive locations have differing ventilation needs. Placement of drive affects the hoist-way
mounting the machine on the guide rails transferring weight down to the pit floor, suspending the machine from
one or more beams tied into the building in the overhead area impacts structural calculations.

The author summarises the advantages of MRL elevators as

 The costs of MRL installation in terms of both contractor time and materials are less than those associated with
traditional elevators for the following reasons:
4. MRL installations require fewer construction materials and less work time: No well holes to be drilled;
no pits to be waterproofed; no requirement for a structural machine- room slab.
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 5. Some models may be installed from the ground up, thus eliminating the need for scaffolding.
6. Some MRL installations do not require a crane to hoist machine or control equipment to the penthouse
floor or to hoist a structural machine-room slab as required for traction elevators. This increases safety
and lessens the project management challenges inherent in some elevator designs. For instance,
hydraulic elevators may require a crane to place the plunger and cylinder in the well hole.

 Installation procedures for MRL technology are highly visible and therefore offer more control over the work
environment

However MRL has design considerations which defer from that of a conventional drive housed in a separate
machine room, and Tetlow [2] suggests conversion of conventional system to MRL system should take place by
gutting of elevator hoist-way and reinstalling required supports and rails.

Asvestopoulos L. [3] reports Elevator equipped with gearless permanent magnet synchronous motors are the
more efficient type of elevator because of the limited energy consumption during travel but have significantly
higher power consumption during standby.

The summarised investigation of energy efficiency of elevator is.

 Doolaard reported on a comparison of the relative energy consumption of hydraulic elevator, traction elevator
and carried out energy measurements for these systems, during a travel of 3 floors in both directions. Results
were then normalized by dividing with the mass of the car.
 Schroeder has developed a generalized equation to calculate the annual consumption of energy of elevator per
square meter of the building space. Use was made of eqn (1) to calculate the daily consumption of energy,
where R is the motor rating in Kilo Watts, SD is the number of starts per day and T is a time factor expressed
in seconds and dependent type of drive and number of floors travelled.
E= R x SD x T / 3600…. (1)

 In the study, 33 elevators of different types were studied and analysed. This study separated the drive
consumption and the standby consumption of energy. The most important finding of this report was that
standby consumption of elevator sometimes is the 80 % of the total consumption of energy. The percentage of
standby consumption for a type of elevator drive increases, as the daily usage gets lower. This was a matter of
concern in low residential buildings with low traffic conditions.
The methodology for energy measurements of elevator defines reference trip as follows:

1. Reference begins trip with open elevator door

2. Elevator doors are closed
3. Travel in a particular direction using the full height
4. Opening and closing of the elevator door
5. Travel in opposite direction using the full height.

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Observations made:

Table 2.1: Specification of measured life [3]

Elevator Hydraulic Geared traction Traction

MRL

Nominal load in 375 300 630

kG

Nominal speed in .5 .6 1
m/s

Travel in m 3.47 12.16 3

Stops 2 4 2

Motor rating in 6 3.5 4.6

kW

Table 2.2: Overview of results [3]

Elevator Hydraulic Geared Traction Traction MRL

Travel energy 18.5 24 9.7

consumption in W-hr

Standby Consumption 37 25 85
in W

Table 2.3: Results after normalization [3]

Elevator Hydraulic Geared Traction Traction MRL

Specific energy 7.1 3.28 5.02

consumed mW/kgm

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The results were summarised as follows:

 Traction elevators with counter weights consume less energy than conventional hydraulic elevators during all
travel.
 It is obvious from Table 2.3 that during travel a MRL elevator consumes less energy than other types. The use
of the permanent magnet technology in place of Gearbox leads to reduced losses and increases the efficiency of
MRL elevator.
 To attach balancing weight in hydraulic elevator can improve the energy efficiency of the elevator
 The High standby consumption has a large effect on the total consumption of energy of an elevator, especially
in low traffic applications.
 Though elevator systems utilize a very small fraction of the total energy consumption in a building, the total
energy consumption of the many millions of elevator is a matter of significance. Energy efficiency of elevator
is a major challenge for elevator industry. Manufacturers are working on improving energy efficiency.

Harvey S. [4] reports that an elevator consumes 5 % of total building electrical supply for a low to medium rise
building. Elevator consumption also includes consumption for HVAC, lighting and other auxiliary services.

The methodology followed was

1. Energy calculations based on first principle

2. Direct measurement of energy use under varying conditions and parameters
3. Simulations based on first principles, engineering data, and traffic models
The results of the study were

 Elevators are engineered systems rather than manufactured products and are tailored or designed to each
installation. Reduction in elevator energy consumption if included as a design parameter ensures that the
elevator is designed for maximum efficiency
 MRL drives with regenerative braking give the best performance, regenerative braking converts energy
dissipated as heat during braking back into the system as electric energy and are more energy efficient
 Using advanced control systems or software which utilize algorithms to carry out proactive actions such as
relocation of all elevators in a lobby to the ground floor in the morning when maximum people enter the
building can help save 5 % more energy in all drive types
 Lighting tax on energy can be reduced by using LED lighting and analog panels instead of haptic panels, use of
LED also reduces elevator cooling load by a small amount
 Utilising various methods in conjunction can yield an energy saving of 30-35 % within elevator classes

Thus it becomes critically important to phase out less efficient drives for MRL or hydraulic drives. The savings
in power consumption alone justify the added cost of redesign and the cost of MRL refit.

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Overall consensus obtained from literature review is that MRL drives provide better performance and energy
efficiency but they have higher inspection and maintenance costs

B. Improvements in present MRL configuration

According to Andrew J.P. [5] the guiding system defines the datum of the spatial relationship between the
elevator and the building which it serves, ensuring that the elevator car and counterweight follow an accurately
defined path through the building with appropriate clearance from equipment associated with the elevator
operation(e.g. landing entrances).In consequence of its function in maintaining the car in a pre-defined path, the
guide rail system will impose forces, particularly lateral forces, on the elevator car via the guide shoes. Although,
as implied above, these forces will be relatively small in normal operation, the quality of the ride experienced by
passengers is directly related to the quality of the alignment and straightness of the guide rail system. During
safety gear operation in particular, the loadings due to the deceleration of the car, and its subsequent support
after stopping, are transmitted to the foundation via the guide rails which, in consequence, are subjected to
significant buckling forces.

George W. G. [6] suggests guide rail mounted MRL causes an eccentric hauling of the car; it is prevented from
tilting by the guide shoes or rollers pressing on the rails. The rail acts as a beam supported by the brackets and it
must have sufficient strength to carry these forces and sufficient stiffness to keep front edge of the platform level
with the landing as loads enter or leave the car. This forces the safety and stabilization component to act as a
load carrying component.

The MRL drive can be supported on a hoist-way spanning beam configuration to eliminate these drawbacks and
provide for easier access to drive for maintenance and inspection.

Advantages of a hoist-way spanning I beam as MRL support as opposed to a guide rail spanning beam are:

 Elimination of eccentric hauling, superior positioning of MRL sheave

 Controller Cabinet may be located in shaft access way decreasing distance between controller and drive
 Ease of inspection and maintenance increases, relative safety increases.

For design of hoist-way spanning MRL Drive support Stephen N.G. [7] Reports Macaulay‘s method as a
favored method of beam investigation within many ‗mechanics of solids‘ modules. This method is a first
exposure to generalized functions (e.g. Dirac delta, step, and ramp), with meaning given over to the bracket
notation, typically of the form [x − a] n; if the argument within the bracket is negative, that is, if x < a, the term
is ignored, while if positive, that is, if x > a, it is treated normally. These terms arise when calculating the
internal bending moment within a beam structure produced by uniformly distributed loading (UDL) when there
are n = 2, concentrated force loads when n = 1, and point moments when n = 0. The load is located at x = a.

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Having so derived an expression for the bending moment which, using this notation is valid at any location along
the beam, the moment–curvature relationship for the (limited-slope) Euler–Bernoulli model is:

M=±EI d2v/dx2

Where the positive or negative sign depends upon the sign convention employed. This allows calculation of the
transverse deflection, v(x), by integrating relatively simple functions twice with respect to the axial coordinate,
x. In practice, the integration is performed with respect to the argument of the bracket, rather than x, in order to
keep the bracket and its meaning intact. For example, x integrates as x2/2 in the normal way, but [x − b]
integrates as [x − b]2/2. Treated normally, ʃ(x-b)dx=x2/2-ax+C1, where C1 is a constant, whereas if integrated
with respect to the argument, ʃ[x-a] dx=[x-b]2/2+C2 , where C2 is also a constant. The difference lies in the value
of the two constants of integration, the latter expression having the additional constant term a 2/2; this difference
is resolved so long as the constants are evaluated with the meaning of the brackets taken into account as per W.
H. Macaulay.

Further according to INSDAG [8] for beam design the elastic critical moment, , is applicable to a beam of I
section which is simply supported at ends. In practical situations, support conditions, beam cross section, loading
etc. vary from this case. Deflection is calculated assuming a simply supported beam with no consideration given
to actual beam support lengths which are only taken into account in the practical stage to check for beam
failures. The lateral restraint provided by the simply supported conditions assumed in the base case is the lowest
and therefore , is the lowest. It is possible, using other restraint conditions, to obtain higher values of ,,
for the same structural section, which would result in better utilization of the section and thus saving weight of
material. Lateral buckling involves three kinds of deformations, lateral bending, twisting and warping, hence it is
feasible to think of various types of end conditions. But, the supports should either completely prevent or offer
no resistance to each type of deformation. The effect of various support conditions is taken into account by way
of a parameter called effective length. The concept of effective length involves the various types of support
conditions. For a beam with simply supported end conditions and no intermediate lateral restraint, the effective
length is equal to the actual length between the supports. When a greater amount of lateral and torsional
restraints is provided at supports, the effective length is less than the actual length and alternatively, the length
becomes more when there is less restraint. The effective length factor would indirectly account for the increased
lateral and torsional rigidities provided by the restraints.

If it is found that the web fails in buckling or bearing, it is not always necessary to select another section; larger
supports can be designed, or load carrying stiffeners can be locally welded between the flanges and the web.
Stiffeners are checked for buckling and bearing in accordance to structural design practices

Web bearing illustrates how concentrated loads are transmitted through the flange/web connection in the span,
and at supports when the distance to the end of the member from the end of the stiff bearing is zero.

The bearing resistance is given by

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Where b1 is the stiff bearing length

n = 5 except at the end of a member

n = 2 + 0.6be/k ≤ 5 at the end of the member

Where be is the distance to the end of the member from the end of the stiff bearing

k = (T + r) for rolled I- or H-sections T is the thickness of the flange t is the web thickness

pyw is the design strength of the web

The Beam deflections obtained may be verified by carrying out FEM analysis in a FEA tool like ANSYS.
However to obtain converging and accurate results there has to be very accurate representation of real world
dimensions, operating conditions and boundary conditions. The element type chosen for analysis also affects the
results obtained.

Majumder G. [9] Studied the maximum deflection and stress analysis of a simply supported beam under
different types of loading. The theoretical calculations were done by using the general Euler-Bernoulli‘s beam
equation. The computational analysis was done on ANSYS software. Comparing the numerical results to those
obtained from ANSYS, showed excellent accuracy of the theoretical calculations. It was noted that in case of
deflection the element type TET 8 Node element gave a closer value in all types of loading than the element type
BRICK 8 Node element. This inference is exactly opposite in case of stress analysis.

B. Impact of new designs on Inspection and maintenance

While MRL technology has established itself as the superior choice for high rise applications, residential
buildings often find MRL inspection and maintenance costs to be prohibitive. Economy in Inspection and
maintenance could remove a major drawback of MRL elevators and allow more residential buildings to move
from traction elevators to the more efficient MRL elevators

Chew M [10] reports in spite of regular and stringent inspections according to elevator maintenance laws defects
are prevalent. From analysis, a defect was observed to have adverse effect on (1) economy, (2) system
performance; and (3) safety and comfort. These factors determine the level of seriousness of a defect and were
considered to establish the significance of a defect. A frequent defect may have insignificant effect, but a very
serious defect may occur rarely.

The three major impacts were defined as:

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● Economic loss: considerable financial damages sustained as a result of the defect, e.g. call back if users are
caught in a stalled car due to deactivated safety switches or faulty circuits.

● System performance loss: here the system performs significantly below normal operating efficiency due to the
defect, e.g. repeated opening and closing of car door.

● Safety and comfort loss: affected safety of the users and maintenance personnel as a result of the defect, e.g.
opening of fire elevator car door in fire floor if the lobby smoke detector is faulty.

It was established that among the defects in vertical transport system, most of the defects can be prevented by
considering three major maintainability criteria, namely, design and specification, construction or installation,
and inspection and maintenance (I and M). It was found that among 28 significant defects, 12 were design
related, 10 were due to faulty installation or poor construction quality and inadequate I and M practises were
responsible for 19 defects. The maintenance quality was largely subjective with regard to cleanliness and
lubrication it was established that the most important contributing factors for maintainability is good
maintenance, followed by good design and material specification, followed by workmanship during construction
or installation. This report highlights the importance of maintenance and inspection for MRL drives. New
configurations of MRL drive which house it on a hoist-way spanning structure at top or bottom of shaft make
inspection and maintenance easy and reduce costs, thereby reducing costs over the elevators lifetime

Ishikawa K. [11] re-affirms the importance of economy in inspection practices. Traditional inspection
approach was to carry out inspection at the end of manufacturing or assembly process Ishikawa criticizes this
approach as it does not promote and process improvement and requires an average of 15 % inspectors to line
workers. Citing inspection as being too little too late too ineffective Ishikawa postulates problem prevention by
carrying out root cause analysis instead of depending on inspection alone to fix errors before they are committed
again.

Clifford M. [12] states in order to implement an effective QC program, the company decides which specific
standards the product or service must meet. Then the extent of QC actions must be determined .Real-world data
may be collected and the results and corrective action decided upon and. If too many unit failures or instances of
poor service occur, a plan must be devised to improve the production or service process and then that plan must
be put into action. Finally, the QC process must be ongoing to ensure that remedial efforts, if required, have
produced satisfactory results and to immediately detect recurrences or new instances of trouble. A
well‐structured Designer Quality Control Plan helps to ensure that designs are economical, constructible,
maintainable and appropriate for their locations and surroundings.

The steps suggested are

1. Inculcate good design principles

2. Identify design inadequacies
3. Cost analysis/Value engineering

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 Use of MRL drives housed in the shaft way in accessible locations satisfies all three of the steps. Use of
MRL drive in particular increases energy efficiency of the system whereas use of hoist-way spanning
configuration for MRL drive support targets and eliminates design inadequacies of earlier iterations of
elevator drive support.

IV.CONCLUSION

Machine Room Less drives represent current pinnacle of elevator drive technology and have made other traction
drives obsolete. MRL drives offer best operating parameters including costs, energy efficiency, ride quality.
When compared to other types of drives for high rise applications and are being preferred to hydraulic drives in
low rise applications. However MRL drives currently in use have few disadvantages including less seismic
safety, eccentric haulage of cabin, difficulty and increased costs of inspection and maintenance. Most of these
disadvantages occur due to older method of Supporting MRL drives on a Beam spanning the Guide rails. Use of
alternate configurations with the drive housed in the hoist way at top or bottom locations (use of pit floor may be
made when moving from hydraulic to traction drives) eliminates majority of disadvantages associated with MRL
drives. Lower costs of inspection and maintenance over the elevator lifetime will also encourage widespread use
of the highly efficient MRL drives

REFERENCES

[1] Celik F. and Korbahti B., ―Why Hydraulic elevators are so popular‖ AsansörDünyasi, Jan-Feb 2006, pp. 48

[2] Tetlow K., 2007, New elevator technology: The machine room less elevator, McGraw Hill construction, New York,
pp. 11–15.

[3] Asvestopoulos L., Spyropoulos N., Kleeman Hellas, Greece, September 2010, ―Lifts Energy Consumption Study‖,
Lift Report Issue 5/2010.

[4] Harvey M.S., April 2005, ―Opportunities for elevator energy efficiency improvement‖, American Council for an
Energy Efficient Economy, Washington.

[5] Andrew J.P., Kaczmarczyk S., Systems Engineering of Elevators, Elevator Books, chapters 10-13

82
[6] George W.G., ELEVATOR HOIST-WAY EQUIPMENT: Mechanical and Structural Design, Elevator World,
Continuing Education, pp 106-110.

[7] Stephen N. G., ―Macaulay‘s method for a Timoshenko beam‖, International Journal of Mechanical Engineering
Education 35/4

[8] Unrestrained Beam Design, Institute for National Development and Growth of Steel, INSDAG.

[9] Mazumdar G., Kumar K., ―Deflection and stress analysis of a simply supported seam and its validation using
Ansys‖, International Journal of Mechanical Engineering and Computer Applications, Vol 1, Issue 5,Special Issue,
October 2013.

[10] Chew M., 2008, ―Quantifying Maintainability Parameters for Vertical Transport System‖, proceedings of 11DBMC
International Conference on Durability of Building Materials and Components, ISTANBUL – TURKEY

[11] Ishikawa, K., 1985, “What is Quality Control: The Japanese way”, Englewood Cliffs: Prentice Hall

[12] Clifford M., June 1998, Case Studies in Engineering Design, Butterworth-Heinemann, Technology and
Engineering, pp. 18-31

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 References

[1] Celik F, Korbahti B., ―Popularity of Hydraulic and MRL Elevators‖ Asansör Dünyasi,
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[2] Tetlow K., 2007, new elevator technology: The machine room less elevator, McGraw
Hill construction, New York, pp. 11–15.
[3] Jay P., 2009, Elevator Systems, APPA Education, Alexandria, Virginia.
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[6] Celik F., ―Compromise in safety in elevator systems‖ Blain Hydraulics,
Pfafenster,2006.
[7] Harvey M.S., April 2005,―Oppurtunities for elevator energy efficiency improvement‖,
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[8] Andrew J.P., Kaczmarczyk S., Systems Engineering of Elevators, Elevator Books,
chapters 10-13
[9] Gibson W.G., ELEVATOR HOISTWAY EQUIPMENT: Mechanical and Structural
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Mechanical Engineering Education 35/4
[13] Unrestrained Beam Design, Institute for National Development and Growth of Steel,
INSDAG.
[14] Mazumdar G, Kaushik K, ―Deflection and Stress Analysis of a Simply Supported
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[15] Kenji I. and Nobuaki M., A Survey of New Products, Systems, and Technology - New
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[17] Ishikawa K., 1985, “What is Quality Control: The Japanese way”, Englewood Cliffs:
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[18] Clifford M., June 1998, Case Studies in Engineering Design, Butterworth-Heinemann,
Technology & Engineering, pp. 18-31
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System‖, proceedings of 11DBMC International Conference on Durability of Building
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