Week – 10

ELEVATOR /LIFT

What is Elevator (Lift)?

An elevator can be defined as an electric lift which is used as vertical transportation
of goods as well as people among the floors in buildings using bins otherwise silos.
As usual, these are activated with the electrical motors that also to drive
counterweight system cables for drive transaction such as a hoist, otherwise, pump
hydraulic fluid for raising a cylindrical piston such as a jack.
These are used in many areas like agriculture, manufacturing, etc. Elevators are
classified into different types based on our requirement. Elevators are frequently used
in the latest multistory constructions, in particular wherever ramps of wheelchair
would be not practical.

Different Types of Elevator

The different types of lifts or elevators include building lift, capsule lift, hydraulic
elevator, pneumatic elevator, passenger lift, freight elevator, traction elevator/cable
driven, residential elevators, machine room-less elevator, etc.
1) Hydraulic Elevator
A hydraulic elevator is power-driven by a piston that moves within a cylinder. The
piston movement can be done by pumping hydraulic oil to the cylinder. The piston
lifts the lift cab easily, and the oil can be controlled by an electrical valve.
The applications of hydraulic elevators involve in five to six-floor buildings. The
operating of these elevators can be done at speeds up to 200 ft or 61 meters for each
minute. All the current hydraulic pumps are designed with a mechanical Y-
delta starter otherwise solid state contractor. For the power supply of motor as well as
building, solid-state starters are superior. Because the windings stay longer as well as
there is no voltage drop across the building power supply.

In Y-delta type starter, the motor can be activated by using two contractors on a
decreased speed, after that continues with full speed. Older hydraulic elevators now
started up suddenly, transmitting mains power at full-blast right into the electric
motor. This sets a lot of damage on the motor, which will make it burn out quicker
than motors on Solid-State or Y-Delta Contactor starters. The hydraulic elevators
are classified into four types such as holed, hole less & roped elevators

2) Pneumatic Elevator
The pneumatic elevator can be designed with an external cylinder, and the cylinder is
a crystal clear self-supporting cylinder. This cylinder includes modular sections to fit
effortlessly into one by one. The top of this tube is designed with steel material that
ensures tight air shutting by suction valves as well as inlets. A lift car runs within the
cylinder, & the head unit on the top cylinder surface consists of valves, controllers,
and turbines for controlling the elevator movements.

Pneumatic elevators are very easy to fit, operate as well as maintain when compared
with the traditional elevators. These are used in existing homes because of their solid
design. The main benefits of using these elevators include solid design & smooth,
speed and flexibility, energy efficient and very safe.
3) Cable Driven or Traction Elevator
The traction elevator or cable driven elevators are the most popular elevators. It
consists of steel cables as well as hoisting ropes that run above a pulley which is
connected to the motor. This is geared otherwise gearless-traction type elevator. In
this kind of elevator, several wire and hoisting cables are connected to the surface of
an elevator car with covering around it on sheaves at one end & the other side is
connected to a counterweight that travels up & down on its guide rails.
The counterweight is equivalent to the car’s weight and half of the weight of the
passenger in the car. This means, throughout the lifting process it needs extra power
for the additional passengers in the car; the rest of the load is managed with the weight
of the counter. When the control system is connected to the lift, then it drives the
motors in a frontward way, and sheave turns around to move the car lift upwards and
stops in the preferred floor where the car is controlled by the weight of the counter.

For the car downstairs movement, overturn occurs during a rotating motor through a
control method. For conserving the energy, some types of lift use electric motors with
four quadrant operation in the regenerative method. Because of the high rise as well as
high-speed capacities, these are applicable in several escalators, lifts, etc.
4) Capsule Lift
Capsule lift or Elevators are used in prestigious buildings, which can be called as
decoration of a building because they improve the building’s beauty as well as carries
life into it.
The main features of this elevators mainly include design, and travel comfort is best.
The interior design of these lifts is attractive with a large glass panel for viewing. The
ultramodern design of these lifts offers a cosmic zone travel experience for the
passengers. These lifts are consistent and inexpensive with the least maintenance.
5) Building Lift
A building lift is a vertical transportation among the floors of the building. These are
frequently used in public buildings, complexes, offices, and multistory building.
These lifts are important in providing vertical movement, mostly in high buildings, for
a wheelchair as well as other non-ambulant building customers. Some type of lifts
also is applicable for emigration & firefighting purposes.
6) Passenger Lift
This type of lift has entirely included a lift car that moves vertically in a specially
equipped lift shaft. Passengers are traveled between the floors in the building at quick
speed. The control systems in the lift frequently designed to offer the most
economical sharing of passengers all over the building. These lifts are very space
efficient which are used in existing buildings where space is at a best.
The main advantages of using passenger lift give a very comfort traveling among
different floors, particularly space efficient, fully fixed shaft, small construction
works, and no level loadings on the building.
7) Freight Elevator
In the world of elevators, these lifts are workhorses. These are very useful for
transporting materials, goods in warehouses, manufacturing industries, shopping
malls, seaports, etc. This type of elevator is separated into classes, to describe their
load capacity as well as application. These lifts are strong in nature, and they are
specially manufactured by engineers.

The features of this elevator include: the range of loading capacity is from 2500 lbs to
10000 lbs, height of the travel up to 50fts. The benefits of these elevators include;
these elevators are designed for commercial as well as industrial applications. The
flexible design to hold the application, door designs can be changed, eco-friendly, etc.
8) Residential Elevators
Residential elevators provide stylish options to the platform as well as stair lifts.
These lifts can be effortlessly incorporated in any available home, otherwise
incorporated in edifice plans for latest homes. These types of elevators are available
in different styles, and these can be installed in your home walls, otherwise included
effortlessly to improve your home’s decoration. The main benefits of residential
elevators are; they can move you securely among floors even during a power failure.
Quick installation and offers you an effortless life.
constructionandworking of lift:

CONSTRUCTION DETAILS: Components of direct acting hydraulic lift:

 Fixed cylinder: It is fixed with the wall of the floor, where the sliding ram reciprocate when
we apply the pressure.

 Cage: It is fitted on the top of the sliding ram where the load is placed (i.e. lifted load).

 Sliding ram: It is fitted in the fixed cylinder which is reciprocate (upward or downward
direction) when we applied the pressure (i.e. reaches the floor wise.)

Diagram
WORKING OF DIRECT ACTING HYDRAULIC LIFT:
When fluid under pressure is forced into the cylinder, the ram gets a push upward. The platform
carries loads or passengers and moves between the guides. At required height, it can be made to stay
in level with each floor so that the good or passengers can be transferred.
In direct acting hydraulic lift, stroke of the ram is equal to the lift of the cage.

major components of lifts :

Cabin/ Car
This is the main part of Elevator which is designed for enclosed transport of passengers & goods

Cable (Rope)
it is used to support the car (passing over the drive sheave to the counterweight) & pull the car.
Usually number of lays depends on load & speed.
 Elevator Machine
A traction machine is used on all traction elevator equipment types. A standard traction machine
consists of a motor, drive sheave, brake and machine bed plate. The traction machine motor turns the
drive sheave shaft to turn the drive sheave. As the sheave turns the hoist ropes pass over the drive
sheave and pull the car through the hoistway.

Controller
An Elevator controller is a system to control the elevators, either manual or automatic.
The controller usually tune down the voltage between 12V to 24V to the controlling system, only the
motor needs 3-phase power supply. The low voltage power supply is for the controlling component
and the fixtures to control the elevator

Drive unit
Everything that works under electricity must have a motor attached for the functioning & driven by
VVVF drives.

The counter weight

In practice, elevators work in a slightly different way from simple hoists. The elevator car is balanced
by a heavy counterweight that weighs roughly the same amount as the car when it's loaded 40%-50%
(in other words, the weight of the car itself plus 40–50 percent of the total weight it can carry). When
the elevator goes up, the counterweight goes down—and vice-versa, which helps us in four ways:

 The counterweight makes it easier for the motor to raise and lower the car—just as sitting on a see-
saw makes it much easier to lift someone's weight compared to lifting them in your arms. Thanks to
the counterweight, the motor needs to use much less force to move the car either up or down.
Assuming the car and its contents weigh more than the counterweight, all the motor has to lift is the
difference in weight between the two and supply a bit of extra force to overcome friction in the
pulleys and so on.

 Since less force is involved, there's less strain on the cables—which makes the elevator a little bit
safer.

 The counterweight reduces the amount of energy the motor needs to use. This is intuitively obvious
to anyone who's ever sat on a see-saw: assuming the see-saw is properly balanced, you can bob up
 and down any number of times without ever really getting tired—quite different

from lifting someone in your arms, which tires you very quickly. This point also follows from the
first one: if the motor is using less force to move the car the same distance, it's doing less work
against the force of gravity.

 The counterweight reduces the amount of braking the elevator needs to use. Imagine if there were no
counterweight: a heavily loaded elevator car would be really hard to pull upwards but, on the return
journey, would tend to race to the ground all by itself if there weren't some sort of sturdy brake to
stop it. The counterweight makes it much easier to control the elevator car.

Hoistway
The space enclosed by fireproof walls and elevator doors for the travel of one or more elevators,
dumbwaiters or material lifts. 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.

Guide Rails
Steel T-shaped or formed sections with guiding surfaces installed vertically in a hoistway to guide
and direct the course of travel of an elevator car and elevator counterweights.

Buffers
The buffer is an apparatus located at the bottom of elevator designed to protect people. Buffers can
stop a descending car by accumulating or dissipating the kinetic energy of the car.

Speed governors
Most elevators have an entirely separate speed-regulating system called a governor, which is a
flywheel with mechanical arms built inside it. Normally the arms are held inside the flywheel by
springs, but if the lift moves too fast, they fly outward, pushing a lever mechanism that trips one or
more braking systems. First, they might cut power to the lift motor. If that fails and the lift continues
to accelerate, the arms will fly out even further and trip a second mechanism, applying the brakes.
Some governors are entirely mechanical; others are electromagnetic; still others use a mixture of
mechanical and electronic components.
 The safety brake
Everyone who's ever travelled in an elevator has had the same thought: what if the cable holding this
thing suddenly snaps? Rest assured, there's nothing to worry about. If the cable snaps, a variety of
safety systems prevent an elevator car from crashing to the floor.

Each car ran between two vertical guide rails with sturdy metal teeth embedded all the way up them.
At the top of each car, there was a spring-loaded mechanism with hooks attached. If the cable broke,
the hooks sprung outward and jammed into the metal teeth in the guide rails, locking the car safely in
position.

Doors
As normal doors, elevator doors are also meant for entry and exit. Elevator door is of two types:
Manual doors and Automatic doors.

 Manual doors: These types of doors are opened with the help of a person who wants to enter the lift.

 Automatic doors: Automatic doors are the type of doors which are automatically opened as it is
powered by a door operator and usually have a full height photo-electric curtain to sense the
entry/exit of persons.

Types of Elevator Motors

Both AC and DC types of electric motors are being used in the elevator services. According to
different service requirements, there are different types of DC and AC motors are employed.

DC Motors
There are different types of DC motors available (series motor, shunt motor and compound
motor). The type of DC motor which is best suited to the given elevator service depends on the
type of elevator service and the speed and the frequency of the slopes.
The elevator motor must not only lift up and down the load, but one of its principle duties is to
accelerate and decelerate the elevator car rapidly. This task must be accomplished smoothly
without jerks which might cause discomfort to the passengers.
The starting torque produced by the DC motor being used as the elevator motor should be at
least 225% of the rated full-load torque. The DC motor having more than 15% speed variation
from no-load to full-load is not suitable for elevator service.
Now, based on different elevator services, following types of DC motors are used −
  For passenger service – Either compound wound DC motors or DC shunt motors give
satisfactory results.
 For freight service – In this service, compound wound DC motors are suitable. The
series winding of the compound wound motor provides a high starting torque, which is an
essential factor for heavy duty work.
Note – Most DC motors, whether compound wound or shunt, have suitable commutating pole
winding so as to ensure the sparkles commutation in both the directions of rotation while using
as elevator motor.

AC Motors
The AC motor used as the elevator motor are asynchronous motor (or induction motor). The
following are the two types of AC motors suitable for the elevator service −
 Squirrel Cage Motor − The squirrel cage motor is used extensively in the elevator
services up to about 20 HP. It is used because of its simplicity and it also requires
relatively simple form of controller. However, the power consumption of squirrel cage
motor is slightly more than that of the slip ring motor, but due to the absence of slip rings
and fewer controller parts, it is somewhat more reliable.
 Slip Ring Motor − The slip ring induction motors are also being used in the different
elevator services. Although, the slip ring motor of same rating is more expensive and has
a lower power factor than the squirrel cage induction motor. Slip ring motors of low speed
type are now available and are being used successfully on elevators whose car speeds are
as high as 400 ft./minute.

Power Requirement of Elevator Motor

In order to determine the power required by an elevator motor for a given installation, following
three factors are to be considered −
 Speed of elevator car
 Load (or net weight) to be hoisted
 Efficiency
In the determination of the load to be hoisted, it is required to consider that the load of the car
and the part of the load is counter balanced by the counter weight. Hence, only the unbalanced
load must be taken into account.
The efficiency is the overall efficiency which considers various frictional and electrical losses.
Thus, the power (in H.P.) of the elevator motor required can be determined using the following
formula −
Powerrequired(inH.P.)=Load×SpeedEfficinecy×33000 Powerrequired(inH.P.)=Load×Sp
eedEfficinecy×33000

Starting Torque Requirements of Elevator Motor

 An elevator requires higher starting torque than is required to keep the same elevator running at
its rated speed and load. It is because of the static friction. Therefore, an electric motor to be
suitable for elevator work, should be capable of developing a starting torque of 2.5 to 3 times of
full-load torque.

Elevator Control System

The elevator control system is employed for the speed control of elevator motors and is broadly
classified into two types −
 Rheostatic control – In a rheostatic control system, a rheostat is included in the field and
armature circuits of the motor and speed control is achieved by varying it.
 Variable voltage control – In a variable voltage control system, the input voltage applied
to the elevator motor is varied by some means and the speed control is achieved.
What Does a Lift Maintenance Engineer Do?
The regular maintenance checks our lift engineers carry out combine detailed inspections of the interior and
exterior of the passenger cabin, and checks on the machine room, the shaft and the pit.

All skilled maintenance engineers have extensive experience in ensuring the ongoing safety of lift
installations, but they all work to a standard checklist which acts as their guide:

Passenger Cabin Lift Maintenance

 Check and replace exterior call button lights,
 Check lift door panels and clearance,
 Check on the firefighter lift controls,
 Operate the lift to check for smooth and accurate acceleration, deceleration and levelling,
 Inspect lift door to ensure that it doesn’t slam or bounce when closing, and that the door restrictor works
effectively,
 Check position indicators and replace burnt out lights,
 Examine the cabin interior for damage or wear and tear to ceiling, handrail, floor, and walls.

Top of the Cabin

 Remove any debris that has accumulated on the top of the cabin,
 Examine the lift shaft for any evidence of vandalism, and rodents or pests,
 Inspect the stop switch and the cabin top inspection station,
 Check the cabling for wear and tear, and examine all connections,
 Inspect the door operator and all components connected to it,
 Check the guide rails, rollers and levelling devices.
 Tower Lifts engineers will always clear any accumulated debris that might be a safety hazard, and
ensure that all working components are clean, lubricated and free from dirt.

Machine Room Lift Maintenance

 Ensure that the machine room is clean and clear any inappropriate materials,
 Inspect all components for any evidence of wear, unexpected vibration, or leakage,
 Check all electrical components for signs of failiure, wear and tear, or overheating,
 Oil level check,
 Carry out component lubrication where, and if necessary.

Our Tower Lifts engineers will always repair faulty machine room components immediately where
possible. Their report will make recommendations as to any follow-on repairs that should treated as a
priority, and more long term component replacements or lift upgrades.

Pit Lift Maintenance

 Check GFI outlet, stop switch and lights are working,

 Inspect the lift cable for any snags or signs of wear,
 Examine condition of guide rails, rollers, and switches,
 Check sump pump operation and clean,
 Inspect spring buffers are securely attached. Check for correct alignment, signs of corrosion.

If any components are showing wear and tear, the Tower Lifts engineer will flag up a concerns, and
schedule remedial action at an appropriate time.

The number or size of lifts required in a building

No regulations specify any mandatory requirements as far as the number of lifts is
concerned. Indian Standards (IS) 14665 Part 2, Section 1, and the National Building
Code (NBC) of India 2016, offer guidelines for traffic analysis calculations, which
determine the handling capacity and response time. Basis this analysis, there are
different recommendations for different types of buildings. For buildings higher than
15 m, there is a need for an eight-passenger fire lift (with automatic doors and speed
sufficient to reach the top floor in 60 seconds), and other requirements as per the Fire
Prevention Act and rules of each State. The NBC 2016 highlights that there is a need
for a stretcher lift in buildings with a height of more than 30 m. As these requirements
vary across States, it is recommended to consult a technical expert for specific cases.

Procedure to procure a lift permit for an existing

building
Lift licenses are currently required in 10 Indian States, including Maharashtra,
Gujarat, Tamil Nadu, Karnataka, Kerala, West Bengal, Assam, Himachal Pradesh,
Haryana and Delhi. Every State’s Lift Act defines the procedures, fee structure and
timelines for obtaining various permissions for lifts and escalators within that State.
The Act contains guidelines for obtaining licenses for existing buildings as well.

Prohibition of mirrors inside elevators

The code of practice prescribed by the Bureau of Indian Standards (BIS) is required to
be followed for lifts and their installations. As per IS 14665 Part 4 of Section 3 clause
#5.8, mirrors can be used inside the elevator car. However, it is recommended that
they should be splinter-proof and not cause injury to passengers in case they are
broken due to any abnormalities.

A building of over 13 m height should have a lift. The lift should be provided from the
ground floor with a capacity of a maximum of six persons. It is recommended to use
IS-compliant lifts and escalators for the safety of equipment and passengers in States
where a Lift Act is not defined. For home lifts, recommended standards are IS 14665
and IS 15259. If it does not have a machine room, then IS 15785, or a similar IS
14671 is recommended. As per IS 15259:2002 Clause #5, a home lift shall have a load
capacity of not less than 204 kg (three passengers) and not more than 272 kg (four
passengers), and a car speed not exceeding 0.2 m per second. Also, a two-person lift is
not recommended for various technical reasons.

Although the lift regulations are complicated with multiple variations, it is advised to
engage a technical expert right from the beginning of the project to ensure that all
norms are complied with.

The Benefits of Lift Installation

Lifts provide a long-term solution for all your heavy-lifting requirements and offer
several benefits.

Some of these are:

 Safe, easy, vertical transportation of goods

 Increased productivity
 Time savings
 Less labor required than carrying goods
 Elimination of the need for forklifts

It only takes five steps for a trained technician to install your new lift.

Erectionproceduresthe Lift :
1. Setting the Columns in Place
First, the technician will make sure that the place you would like the lift installed is a
good option. They will suggest alternatives if necessary. Remember:

 There should be enough space to work safely without impacting your

workflow.
 The floors on both levels need to be sturdy enough to support the lift system
when loaded. They will also check that there’s enough overhead clearance for
loading and off-loading the cargo.
 They will bolt the columns and guide columns into place.

2. Adding the Carriage

Outlines will be drawn on the floor and walls to ensure that the carriage is placed in
the correct location to travel up the columns evenly and level. The carriage is placed
inside the columns in the exact position indicated by these markings. Wheelblocks
will be fitted to the columns and bolted to the carriage uprights accordingly. Lift
chains are installed and connected to the wheelblocks. These should not run off the
sprocket when the carriage is raised.

3. Raising the Drive Base for Mechanical Lift Installation

If you are installing a mechanical lift, the drive base will be lifted into place on top of
the columns. When the motordrive is fitted correctly, the drivebase will be bolted in
place and later, welded to the supports.

4. Assembling and Setting the Gates and Enclosures

Gates and enclosures are important to prevent items from slipping off the VRC and
injuring someone. These should be welded firmly into place.

5. Wiring the Electrical Components

Your technician will take care of all the wiring that makes your lift go up and down.
This will ensure that the lift is easily operated at the flick of a switch. They will also
make sure that the lift is working properly and that it can be operated safely by any
one of your employees.

A Final Check
The last step in a successful lift installation involves a thorough inspection of the unit.
Then, your employees or a designated operator will be shown how to operate the lift
safely. This should serve as the final operational check for your lift.

Lift installation is the perfect solution to help your business grow quickly. What are
you waiting for? Get in touch and let’s take your business to the next level. We offer
tailor-made solutions to suit your needs.
 ESCALATORS
construction andworking of escalators :

Escalators are mechanical devices used for transporting people vertically between different levels of buildings.
Typically, they take the form of a moving staircase, consisting of a 'chain' of single-piece aluminium or stainless
steel steps guided by a system of tracks in a continuous loop.

Escalators are commonly used in buildings where the movement of a large number of people is required, such as
shopping centres, airports, transit systems, exhibition halls, hotels, arenas, public buildings, and so on.

They occupy the same physical space as a staircase, generally have no waiting time (other than during periods of
congestion), allow a greater flow of people, and can be more practical than lifts. It is also possible for people to walk
up or down escalators, if they are in a hurry, or if they break down.

A variation of the escalator is the moving walkway, which transports people horizontally.
Escalators Basic Components

The Escalator consists of the following components:

1. Landing Platforms.
2. Truss.
3. Tracks.
4. Steps.
5. Handrail.
6. Escalator Exterior (Balustrade).
7. Drive system.
8. Auto-Lubrication System.
9. Braking system.
10. Safety devices.
11. Electrical & Control Systems

Escalator components

The following components make up an escalator system:

Landing platforms

These contain the curved sections of the tracks, in addition to the gears and motors. The floor plate
provides space for users to stand before stepping onto the moving steps. The comb plate has a series of cleats (like
the teeth of a comb), that mesh with matching cleats on the edges of the steps and minimise the gap between
the stair and the landing.

Truss

The structure that bridges the lower and upper landings, and carries the straight
track sections. Steel or concrete supports connect the ends of the truss to the top and bottom landing platforms.

Balustrade

This is the structure supporting the handrail of the escalator and can be made of metal, sandwich panels or glass.

Handrail

The handrail moves courtesy of a chain connected to the main drive gear by a series of pulleys. It is generally made
from a blend of synthetic polymers and rubber, and is designed to be very durable.

Tracks

The step-wheel track for the front wheels of the steps, and the trailer-wheel track for the back wheels of the steps,
cause the steps to form a staircase as they move from under the comb plate.

Steps

These are typically solid and made of die-cast aluminium or steel. They are cleated with comb-like protrusions
that mesh with the comb plates. The steps are linked by a continuous metal chain that forms a closed loop.

The steps, connected in series, always step level as they move. The steps create a flat platform at both the top and
the bottom of the escalator by collapsing on each other. This works by way of the two sets of wheels on each step.
The upper set of wheels are connected to the rotating chains, pulled by the gears at the top of the escalator. The
lower set of wheels follow behind and just glide along on their track.

Motor

Escalators are driven by a motor and chain system inside the truss. At its core are a pair of chains looped around two
pairs of gears. The gears at the top of the escalator are turned by an electric motor, which in turn rotates the chain
loops. The electric motor also powers the moving handrail which is looped around a series of wheels and is
configured so that it moves at a similar speed to the steps.

Operation and maintenance of escalator :

Escalators are complex, with a great number of moving and stationary parts; mechanical,
electrical and electronic components along with various surfaces and fixtures that interact with
the riding public. While no facility owner or maintenance team can be expected to understand all
the nuances between brands or product iterations, there are some general practices to follow that
will help avoid major issues or disruption.

 Check that protective barriers are in place and not damaged. Check that displayed
instructions for the riding public are present and in good shape.
 Check the functions (operation and display) of stop switches, key switches, directional
indicators and digital displays – replace as needed.
 Ensure safety lighting is working, including skirt, comb plate and step gap.
 Check condition of inner skirts and skirt brushes for wear, proper attachment or damaged
pieces.
 Comb fingers should be replaced if a finger is broken or damaged. Loosen comb finger
screws once a year and lubricate the threads.
 Check comb plates for proper movement and adjustment, confirm that guides are
lubricated and electrical contacts are prepped for operation.
 Inspect steps for broken tread ribs or other damages and replace as needed.
 Inspect handrails for overall wear or damage in any section including the back side of the
handrails. Check handrail belt tension and adjust to the manufacturer’s specifications.
 Ensure anti-static brushes are present and functioning. Handrail guides should be aligned
and replaced if worn.
 Check condition of the pit area for damaging standing water and proper lighting in case
work needs to be done. Ensure smoke detectors are functioning. Check the water level
monitor for operation. Check operation of any ventilating fans.
 Check the condition of step chains regularly. Inspect for link and axle wear as well as the
tracks or guides the chain rides in. Lubrication brushes must be touching the chain itself.
Check chain tension and replace the chain if it is excessive.
 Check condition of any drive chain—motor or handrail—for excessive wear or sagging.
Lubricate chains as required. Inspect all drive sprockets for excessive wear.
 Check the operation of the service and safety brake. Replace any worn parts or brake
linings.
 Inspect the operation of the handrail speed monitor, upthrust sensors, step level sensors,
vibration sensors, speed monitors, skirt contacts and handrail entry contacts.

This surely isn’t a one-size-fits-all list, but the concepts offered do apply generally. Escalator
maintenance will vary across manufacturer, application requirements, local conditions and the
service provider contract. If you do involve a third-party provider, ensure as best as possible that
the service provider is qualified to work on your equipment. Escalators are complex systems and
well beyond the basics discussed here, technicians are highly trained to rise to the rigors and
safety hazards that come along with the occupation.
 INDUSTRIALOVERHEADCRANES
INDUSTRIALOVERHEADCRANES :

An overhead crane, commonly called a bridge crane, is a type of crane found in industrial environments.
An overhead crane consists of parallel runways with a traveling bridge spanning the gap. A hoist, the lifting
component of a crane, travels along the bridge. If the bridge is rigidly supported on two or more legs running
on a fixed rail at ground level, the crane is called a gantry crane (USA, ASME B30 series) or a goliath crane
(UK, BS 466).
Unlike mobile or construction cranes, overhead cranes are typically used for either manufacturing or
maintenance applications, where efficiency or downtime are critical factors.
The most common overhead crane use is in the steel industry. At every step of the manufacturing process, until
it leaves a factory as a finished product, steel is handled by an overhead crane. Raw materials are poured into a
furnace by crane, hot steel is stored for cooling by an overhead crane, the finished coils are lifted and loaded
onto trucks and trains by overhead crane, and the fabricator or stamper uses an overhead crane to handle the
steel in his factory. The automobile industry uses overhead cranes for handling of raw materials. Smaller
workstation cranes handle lighter loads in a work-area, such as CNC mill or saw.
Almost all paper mills use bridge cranes for regular maintenance requiring removal of heavy press rolls and
other equipment. The bridge cranes are used in the initial construction of paper machines because they
facilitate installation of the heavy cast iron paper drying drums and other massive equipment, some weighing
as much as 70 tons.
In many instances the cost of a bridge crane can be largely offset with savings from not renting mobile cranes
in the construction of a facility that uses a lot of heavy process equipment.

How Overhead Cranes Work

When it is necessary to move bulky materials or extremely heavy loads through a manufacturing
facility, it is more convenient and efficient to use an overhead crane instead of struggling to
navigate aisles and floor space. Overhead cranes lift, lower, and move horizontally along a rail or
beam and are capable of safely lifting extremely heavy loads. The travel and speed of the crane is
controlled by an operator using a pendant station or wireless control.

Overhead cranes cover a rectangular area and are able to move loads from side to side as well as
forward and backward. Though not every overhead crane is the same, they do have certain
standard features such as a hoist, trolley, beams, girders, and control systems.

How Overhead Cranes Work

Bridge
The bridge of an overhead crane runs longitudinally along tracks laid on runway beams over the
rectangular working area. Bridges are made of steel girders that are connected to runways at
either end of the girders.
Lifting Trolley
The lifting trolley contains the lifting mechanism that has a brake, motor, reducer, drum, and set
of pulleys. The motor drives a drum that rotates through the reducer to drive the wire rope or
chain that raises and lowers the load.
 Driving Mechanism
There are two parts to the driving mechanism of a crane. There is the long transmission that
drives the wheels on both sides, while a separate motor drives each set of wheels individually.

Power Supply
The power supply is a complex subject since there are so many different types of power systems
with different connections for each type of system. The three common types are conductor bar,
festoon system, and cable reels.

The majority of overhead cranes depend on electricity for their power supply though there are
versions that run on pneumatic power versions. The cable festoons, conductor bars, or reel cables
transfer power to the crane runway and bridge crane control. This power feed is used to power
the trolley and hoist.

 Conductor Bar – A conductor bar system is installed on the crane‘s runway or monorail. They can be used
on runways with more than one bridge. Power is supplied through a sliding shoe collector system, which
is safer than other methods.
 Festoon System – A festoon system can be track, I beam, or square rail mounted. They use flat or
round cables on a trolley that moves along the track. The cable hangs below the track and
expands or retracts depending on the position of the trolley.
 Cable Reel – Spring loaded or motorized cable reels are used to release, retrieve, and store the
conductor cable. This method is used for mainline power along a runway or monorail.

Height
The height at which the crane is installed has a bearing on the type of motor and the capacity of
the crane. The lift height for an overhead crane is the distance from the floor to the saddle of the
hook, which is a crucial measurement since it ensures there is enough lift room as well as area to
reposition the load.

Another important factor is the C dimension, the maximum height to which the hook can be
lifted. The C dimension is the measurement from the trolley wheels to the hook saddle.
Controls
Each part of an overhead crane's movements is controlled by software and electronics that are
designed to work in unison for safety and ease of operation. Overhead crane controls give the
operator full control of the load at all times. The most basic form of controls have a start and stop
button, while more advanced controls have joysticks and tablets to program a wider range of
motions and movements. Programmed into the controls are the limitations of the crane, which
determines what it can do and where it can move. Control systems provide usage data,
diagnostics, and methods for controlling possible errors in operation.

Hoist
The two main types of hoists for an overhead crane are chain and wire. A chain hoist is held in
place by a chain holder and is designed for lifting loads of less than ten tons. They provide true
vertical lift and rise straight up without any lateral drift.

Wire rope on hoists are hooked to the load and capable of lifting ten tons or more. They allow for
more options and greater flexibility. Unlike chain hoists, wire rope hoists are susceptible to
lateral movement.
Uses for Overhead Cranes
Warehousing
Assembly
Transportation
Equipment Repair

Overhead Crane Construction

The construction and choice of an overhead crane involves the investigation of several
factors beyond what needs to be lifted or the type of materials being loaded. Since
overhead cranes are designed, shaped, configured, and engineered to fit predetermined
conditions, it is important to have a complete understanding of how the crane will fit into
the operation.

It is extremely important to carefully plan and prepare for the installation of an overhead
crane. Manufacturers work closely with their clients to ensure what is planned and
installed exactly meets the needs of the customer.
 Overhead Crane Construction
Span
The span is the distance between the runway rails, which is one of the more costly
aspects of the construction process. A longer and wider span determines the amount of
material required to construct the girders, which increases the cranes weight and cost.

Load Capacity
The determination of a crane‘s capacity is the maximum load that may be applied to the
crane under the required working conditions. When figuring the load capacity, the first
condition is the size and weight of the material to be lifted. Once the load capacity is
determined, the type of hook and hoist can be decided.

In cases where the crane will have a large span, capacity, and must endure severe
circumstances, a double girder design may be necessary. For extra strength, double
girders are made of welded reinforced steel.

Classification
Overhead cranes have six classifications established by the Crane Manufacturer
Association of America (CMAA). The determination of a crane‘s classification uses these
criteria:

 Frequency of use
 Speed of material transfer
 Number of lifts per hour
 Maintenance cycle
 Average load
 Number of full capacity lifts
 Work environment

Operation and maintenance over headcranes :

Crane maintenance repair cycle:

 A period of one to three months
 Time of four to eight hours
 Crane maintenance repair contents:
 The replacement of the wire rope worn reached the limits. For safety, casting lane, lane rope front will be
replaced once about every six months, to ensure good lubrication.
 The replacement of badly worn pins, screws.
 The replacement of the brake shoe reached wear limit (50% of original thickness).
 The replacement of damaged hook, shields, pulley; hook inspection once a year.
 The adjustment part of the installation, the deviation caused by the use and eliminate hidden dangers.
 The replacement of the failed safety device.
 Repair or replacement the motor brushes, controller, contactor contact burns.
 Limit adjustment.
 The replacement the motor.
 Took over the inspection of gear wear; replacement the parts to be scrapped. Driving casting lifting
mechanism, coupling, dismantling once every 3 months to ensure good lubrication.
 Check the reel.
 Change gear (traveling crane) clean oil or replace the main drive gear.
 The lubrication points refueling to ensure good lubrication.
 Deal with the problem usually found in the inspection point.
 Replace the brake

HVAC System
HVAC Stand For

HVAC stands for heating, ventilation, and air conditioning. It is becoming increasingly common
to see HVAC spelled as HVACR, which expands the original definition to include refrigeration.
HVAC System Parts and Diagram

Image from 21celcius

There are different parts for a HVAC system based on its application, but one can consider what
occurs in a evaporative cooling system as a widely used case throughout the world and get a sense of
what is generally happening in the system. The logic for heating is in a way similar and can be
deduced from here. Now, the key components for a cooling system include the expansions valve,
evaporator, compressor, condenser, and drier.

The expansion valve induces a pressure drop in the fluid that expands its volume. The evaporator is
where the refrigerant fluid absorbs heat through the process of evaporation to cool down the stream
entering the warm environment. The compressor is what makes the flow of the refrigerant possible.
Condenser is what that rejects the heat into the outside air to and return the refrigerant to its initial
state. Receiver drier is where the contaminants are removed from the refrigerant to ensure better air
quality.

Main Components of an HVAC System

Every HVAC system contains six primary parts that it needs to operate. When one or more of
these parts stop functioning properly, there are problems ranging from uneven temperature
distribution to poor air flow. It is an HVAC technician’s job to listen to customers, identify their
issues and diagnose the trouble in the system which parts of the system are most likely to cause
trouble. Here is an overview of the six main components of a heating, ventilation, and air
conditioning system.

Thermostat

This is the part that you interact with directly. The thermostat instructs the HVAC to perform a
specific task. It also helps stabilize the temperature in a home or building, which affects air
quality as well as humidity levels. When a thermostat is not properly calibrated or installed
correctly, it can cause a system to work overtime, not work enough or ineffectively heat or cool a
space.

Heat Exchanger

Heat exchangers are responsible for heat transference. They move heat from one place to
another, and it is used in both heating and cooling. An air conditioner uses a chemical liquid
called a refrigerant to move heat and turn it into cool air that is blown through ducts and vents
into a room. With gas furnaces, the exchanger warms indoor air using combustion gasses from
the furnace and distributes the warmed air throughout a space; exhaust is vented through a flue
outside to prevent poisoning.
Evaporator Coil

The evaporator coil absorbs heat from hot indoor air so it can be cooled by refrigerant and
distributed through air conditioning. It turns the liquid refrigerant into a gas or vapor and is
essential to the heat exchange process. If an evaporator is frozen, damaged, or dirty, an HVAC
system can stop heating and cooling or work strenuously to produce poor results. This ultimately
wears down the entire unit and leads to more breakdowns and system failure.

Condenser Coil

A condenser coil is similar to an evaporator coil, but it has the opposite job. Instead of drawing
hot air from inside, the condenser coil releases hot air outdoors. It allows for the cycle of air
circulation and filtration to occur by releasing the hot refrigerant vapor that builds up in a room.
A fan blows over the condenser coil to rapidly cool the hot air and condenses into a liquid again;
the liquid in the condenser coil is returned to the evaporator coil, which allows it to return to a
gas or vapor again.

Combustion Chamber

The combustion chamber is also known as a burner, and it is the part of an HVAC system that
heats cool air. When an HVAC system is set to heating, air from the furnace is ignited with a
combustible material to produce heat for warming the air. Older models previously had manual
combustion chambers that required a pilot light to work. Because they were less safe and
produced higher levels of carbon monoxide, they are now considered outdated and, in many
places, obsolete. Instead, automatic glow sticks are used to seamlessly ignite in the furnace and
heat a home or building.

Blower Motor

Finally, the blower motor is responsible for moving the cool or hot air throughout an HVAC
system’s ductwork. This is done using electricity, which powers the motor and uses a fan to
circulate the air. All the ducts lead to separate supply and return vents situated throughout a
home or building. Commercial and industrial HVAC systems have much more powerful motors
to evenly distribute air throughout a large space; residential units are smaller and typically have
simpler designs, which make them easier to repair and maintain.

Chiller:
A chiller is a cooling system that removes heat by circulating heat-absorbing a refrigerant
through a series of mechanisms through which the heat is released. The essential
components of a chiller are a compressor, condenser, expansion valve, and evaporator.
They work in unison to circulate a refrigerant that removes heat from a process,
operation, or space.

There are several different types of chillers, each of which has a different process for
removing heat. All chillers use air or water as a cooling method. For example, air cools a
chiller system using fans, while a water-cooled chiller circulates water with a cooling
tower.

Aside from the two cooling processes, chillers are further differentiated by the type of
compressor they have. Compressors in all chillers have the same function: to compress
the refrigerant and increase its temperature and pressure before it moves on to the
condenser. There are several variations as to how the compressor completes its function.

There are several variations as to how the compressor completes its function.

Chillers operate on the principle of compression or absorption of a vapor. They are

designed to provide a continuous flow of coolant to maintain a preset temperature. As the
diagram shows, they are a continually circulating system of fluid that lowers the
temperature by reducing heat.

AIR HANDLING UNIT (AHU):

An air handling unit, commonly called an AHU, is the composition of elements mounted in large, accessible
box-shaped units called modules, which house the appropriate ventilation requirements for purifying, air-
conditioning or renewing the indoor air in a building or premises.
Main functions of an AHU
In addition to managing the proper ventilation of the interior with outside air, the AHU performs other
functions:

 Filtration and control of the quality of the air that will reach the interior, thanks to the air purification
filters, and depending on the retention of these filters, the air will be clean.
 Control of the air temperature that regulates the air conditioning system in cold or hot, so that the
thermal sensation in the interior is the desired one.
 Relative humidity monitoring for greater indoor comfort.

For its part, the places for which the AHU is intended are those in which the flow of people is very large and
accumulates many people at the same time and whose natural ventilation is limited: hotel dining rooms,
function rooms, restaurants, convention halls... It is also a suitable option for those spaces with very high
hygiene requirements: laboratories, clean rooms or operating theatres, among others. An AHU can also be used
to ventilate places where air conditioning is provided by radiators or underfloor heating,

Construction of AHU:

 Air intake: air handling units collect air from outside, which is treated and distributed throughout the
rooms; and/or indoor air that is "recycled".
 Filter: depending on the air purity requirements, the filter applied will have a higher or lower particle,
viruses, bacteria, odours, and other air pollutants retention.
 Fan: this is an electromechanical system that powers the air to expel it from the AHU to the ducts that
distribute the air throughout the rooms.
 Heat exchangers: devices that transfer temperature between two fluids, in this case, coolant and air,
separated by a solid barrier.
 Cooling coil: the air passing through this module is cooled. In this process, water droplets can be
generated, which are collected in a condensate tray thanks to the built-in droplet separator.
 Silencer: coatings that considerably reduce the sound level of the installation.
 Plenums: empty spaces in which the air flow is homogenised.

FAN COIL UNIT (FCU):

 A fan coil unit (FCU), also known as a Vertical Fan Coil-Unit (VFC), is a device consisting of
a heat exchanger (coil) and a fan. As part of an HVAC system found in residential, commercial, and
 industrial buildings using ducted split air conditioning or with central plant cooling, a fan coil unit is
often connected to ductwork and a thermostat to regulate the temperature of one or more spaces as
well as assisting the main air handling unit for each space if used with chillers. The thermostat
controls the fan speed and/or the throughput of water to the heat exchanger using a control valve.
 Owing to their simplicity and flexibility, fan coil units can be more economical to install than
ducted 100% fresh air systems (VAV) or central heating systems with air handling units or chilled
beams. Various unit configurations are available, including horizontal (ceiling mounted) or vertical
(floor mounted).
 Noise output from FCUs, like any other form of air conditioning, is principally due to the design of
the unit and the building materials around it. Some offer noise levels as low as NR25 or NC25
 The output from an FCU can be established by looking at the temperature of the air entering the unit
and the temperature of the air leaving the unit, coupled with the volume of air being moved through
the unit. This is a simplistic statement, and there is further reading on sensible heat ratios and the
specific heat capacity of air, both of which have an effect on thermal performance.

Methods to reduce energy consumptiontowardsHVAC :

1. Turn it up one degree. ...

2. Use a smart thermostat and program a schedule. ...

3. Keep ducts clean and airflow clear. ...
4. Schedule regular maintenance visits. ...
5. Change air filters. ...
6. Retrofit your AC unit. ...
7. Upgrade to an energy efficient air conditioner.
8. Insulate your space to keep cool air in