lift and escalator.pdf

LIFTS AND ESCALATORS
AR. DEEPIKA VERMA

• A lift or elevator is an appliance to transport men or material two or more floors in
a vertical direction by means of a guided car or platform. The necessity of lifts in
multi storied buildings has been so well recognized that no multi storied building
is planned without proper provision for lifts.
• It is mandatory to install elevators in all buildings more than 24 m in height
• Mechanisms of lifting objects through hoists and primitive elevators were use in
as early as the third century B.C. operated by human and animal power or by
water wheel. However after 13th century these devices were improved with pulley
they were capable of differential speeds like gears; they could move heavier
loads.

• Elevator car : That part of an elevator that includes
the platform, enclosure, car frame, and door.
• Machine beam : A steel beam, positioned directly over
the elevator in the machine room and is used to support
elevator equipment.
• Machine room : This usually located at the top of the
shaft and accommodates the winding machine, etc.
• Pit : That part of an elevator shaft that extends from the
threshold level of the lowest landing door down to the
floor at the very bottom of the shaft.
• Shaft : A hoistway through which one or more elevator
cars may travel.
• Counterweight or balance-weight: A unit, consisting
of Steel weights, which counter balance the weight of the
car and a portion of the load, and to which the
suspension ropes are attached.

• Traction drive : Lift whose lifting ropes are
driven by friction in the grooves of the driving
sheave of the machine.
• Trailing cable : Flexible cable providing
electrical connection between the lift car and a
fixed point or points.
• Bottom clearance : The distance, including
buffer compression, the platforms could travel
below the bottom landing until the full weight of
the car, when loaded, rests on the buffer.
• Top clearance :The vertical distance between
the top car attachment and the bottom of the
diverting pulley or any steelwork supporting
equipment; there must be an adequate margin
between this and the car will not contact the
diverting pulley or steelwork.

• Guide rails : These, fixed truly vertical in the shaft, are of steel and serve to guide
the movement of both car and counterweight.
• Passenger Lift : A lift designed for the transport of passengers.
• Goods Lift : A lift designed primarily for the transport of goods but which may carry
a lift attendant or other person necessary for the unloading and loading of goods.
• Service Lift (Dumb-Waiter) : A lift with a car which moves in guides in a vertical
direction; has net floor area of 1 m2, total inside height of 1.25 m; and capacity not
exceeding 250 kg; and is exclusively used for carrying materials and shall not carry
any person.
• Hospital Lift : A lift normally installed in a hospital/dispensary/clinic and designed
to accommodate one number bed/stretcher along its depth, with sufficient space
around to carry a minimum of three attendants in addition to the lift operator.

The size and number of lifts depend on two basic considerations-the quantity and
quality of service desired. Quantity of service gives the passenger handling capacity of
the lifts during the peak periods and the quality of service is measured in terms of
waiting time of the passenger at various floors. This is a complex matter and there is no
simple formula for determining the most suitable lifts However, the number of
passengers lifts and their capacities, i.e. load and speed, required for a given building
depend on the characteristics of the buildings.
The most important characteristics are
• The number of floors to be served by the lifts
• The pitch of the floor; i.e. floor to floor height
• The population of each floor to be served.
• The maximum peak Demand This demand may be unidirectional as in Up/Down
peak periods or a two-way traffic movements.

• The handling Capacity is calculated by the following formula:
• H= 300 x Qx 100
T x P
Where,
H= Handling Capacity as the
percentage of peak population
handled during five minutes
Q= Average number of
passenger carried in a car,
T= Waiting Interval in seconds,
P= Total Population to be
handled during peak morning
period.

• The waiting time (T) is calculated by the following formula,
• T= RTT = Round Trip Time
N N
Where
RTT = It is the average time required by each lift in taking one full load
of passenger from ground floor discharging them in various floors and
coming back to ground floor for taking the fresh passengers for the
next trip including entry, door opening/ closing, stopping, etc.,
N= Number of Lifts

• The lift manufacturer should specify the particulars
of full load current, starting current, maximum
possible voltage drop, size of switches and other
details to suit requirements. The electrical
engineer/ authorized and licensed contractor must
ensure that every detail as approved is followed
strictly.
• A separate three phase electric meters must be
installed for individual lift with 400 mm2 x3.5 core
copper armored cables running from meter rooms
to the machine rooms.
• Another 2.5 mm2 x 3 core copper armored cable
should be provided from meter room to a machine
room and again to the bottom of the lift well.
• Every lift should be provided with two main
switches of 32 A capacity ICP (Iron Cladded
Tripped Pole) One main switch should be provided
in meter room and another in machine room.
• The cables from the meter room to lift well should
be underground, and then inside lift well. Cable
should run on backside wall near one of the corner
of the lift well up to the location of main switches in
machine room.

Advantages Disadvantages
• Lower cost of equipments & its
maintenance than traction lifts (twice).
• Performance of hydraulic elevator
becomes erratic as the oil in the
system varies in temperature.
• More efficient building space utilization
than tractions.
• Eg., hydraulic lifts would require
• 9.6 sq m less floor space than
tractions.
• Moreover overhead machine room isn’t
required.
• Since it has no safety device to prevent
its falling it depends wholly on the
pressure .
• Most effective for high load capacity
requirements , that is why it is highly
used for freight, automobile elevators.
• Inherently high heat producing device.
• Since it imposes no vertical loads on
the building structure, column sizes
can be reduced significantly in the
hoistway area.

1. HYDRAULIC LIFTS
Pascal's Principle state that the
pressure given to liquid in closed
chamber will be continued by the liquid
to every direction with uniform and the
same magnitude. ‘

Advantages Disadvantages
•Lower cost of equipments & its
maintenance than traction lifts (twice).
•Performance of hydraulic elevator becomes
erratic as the oil in the system varies in
temperature.
•More efficient building space utilization than
tractions.
Eg., hydraulic lifts would require
9.6 sq m less floor space than tractions.
Moreover overhead machine room isn’t
required.
•Since it has no safety device to prevent its
falling it depends wholly on the pressure .
•Most effective for high load capacity
requirements , that is why it is highly used
for freight, automobile elevators.
•Inherently high heat producing device.
•Since it imposes no vertical loads on the
building structure, column sizes can be
reduced significantly in the hoistway area.

2. TRACTION LIFTS (MACHINE LIFTS)
• Principle : see – saw
the car is raised and lowered by traction steel
ropes
rather than pushed from below.
• The ropes are attached to the elevator car, looped
around a sheave &connected to an electric motor.
• when the motor turns one way, the sheave raises
the elevator; when the motor turns the other way,
the sheave lowers the elevator.
• Typically, the sheave, the motor and the control
system are all housed in a machine room above
the elevator shaft.
• The ropes that lift the car are also connected to
a counterweight, which hangs on the other side of
the sheave.

• the counterweight and the car are perfectly balanced.
• Basically, the motor only has to overcome friction -- the weight on the other side does
most of the work.
• In gearless elevators, the motor rotates the sheaves directly. In geared elevators, the
motor turns a gear train that rotates the sheave.
• Nowadays, some traction elevators are using flat steel belts instead of conventional
steel ropes. Flat steel belts are extremely light due to its carbon fiber core and a high-
friction coating, and does not require any oil or lubricant.

• The entrance door shall have sufficient
opening to allow for in & out of
machines.
• shall not be any common wall/slab
between machine room and water tank.
• shall not be used as a store room or for
any purpose other than housing the
machinery connected with the lift
installation.
• shall not act as a passage to any other
room or utility.
• adequately ventilated.
• shall be such that the equipments are
protected as far as possible from dust
and humidity.
• Temperature 5 deg C – 40 deg C
• walls, ceiling, floor should be finished
in tiles or painted as a min to stop dust
circulation.

Traction (Machine) Hydraulic
• lifted by ropes, which pass over a wheel
attached to an electric motor above the
elevator shaft.
• supported by a piston at the bottom of the
elevator that pushes the elevator up as an
electric motor forces oil or another
hydraulic fluid into the piston.
• used for mid and high-rise applications.
• Much higher travel speed than hydraulic.
• used for low-rise applications of 2-8
stories.
• Principle : see - saw • Principle : Pascal’s pressure principle
• Components : control system, sheave,
motor, counterweight, guiding rail.
• Components : tank, motor, valve, actuator.
• The machine room is located at the upper
most level, i.e., on the terrace.
• The machine room is located at the lowest
level adjacent to the elevator shaft.

Elevator manufacturers are producing premium elevators for mid- and high-rise
buildings that are extremely energy efficient. These traction elevators have improved
controls, hardware, and other systems that not only use less energy, but are much more
compact, efficient, and even generate electricity that a facility can use.
Reducing Overall Energy Usage with Control
Strategies:
The most energy efficient elevators now have:
• software- and microprocessor-based controls
instead of electromechanical relays
• in-cab sensors and software that automatically enter
an idle or sleep mode, turning off lights, ventilation,
music, and video screens when unoccupied
• destination dispatch control software that batches
elevator stop requests, making fewer stops and
minimizing wait time, reducing the number of
elevators required
• personalized elevator calls used with destination
dispatch controls that eliminate the need for in-cab
controls.

Regenerative drives are another remarkable advancement in energy-efficient elevator
technology. They recycle energy rather than wasting it as heat.
The permanent magnet motors in Otis’ ReGen drives are capable of bidirectional
energy flow. Magnatek’s Donald Vollrath explains how they operate in his Elevator
World Continuing Education Program “Regenerative Elevator Drives: What, How and
Why.” When power flows into the motor, it creates a lifting torque on the shaft and
elevator sheave, lifting the carriage. When the carriage travels down, the motor acts as
a generator, transforming mechanical power into electrical power and pumping current
back into the facility’s electrical grid to use elsewhere.
When a cab goes up with a light load and
down with a heavy load, the system generates
more power than it uses. Over time these small
amounts of power generated during each
elevator’s sporadic decelerations add up to
noticeable savings. They use less energy than
non-regenerative drives, and reducing the
excess heat in the building.
The most energy efficient types of elevators are
machine-roomless (MRL) traction elevators.
These space-saving improvements eliminate
the need to build and supply energy to a
machine room and consume significantly less
energy than the larger versions previously
used. They also generate less heat.

A moving staircase – a conveyor transport
device for carrying people between floors of a
building.
consists of a motor-driven chain of individual,
linked steps that move up or down on tracks,
allowing the step treads to remain horizontal.
Are used to
move pedestrian
traffic in places
where elevators
would be
impractical like
shopping
malls, airports, c
onvention
centers.

•The core of an escalator is
a pair of chains, looped
around two pairs of gears &
an electric motor runs it.
•The motor and chain
system are housed inside
the truss, a metal structure
extending between two
floors.
•As the chains move, the
steps always stay level.
•At the top and bottom of
the escalator, the steps
collapse on each other,
creating a flat platform. This
makes it easier to get on
and off the escalator.
Conventional Mechanism

• Each step has two sets
of wheels, which roll
along two separate
tracks.
• The upper set (the
wheels near the top of
the step) are
connected to the
rotating chains.
• The other set simply
glides, following
behind the first set.
• the electric motor also moves the handrail, a rubber
conveyer belt, moves at exactly the same speed as the
steps, to give riders some stability.
• Each step has a series of grooves in it, so it will fit together
with the steps behind the tracks.
Modern Mechanism

Difference between Lifts & Escalators
LIFTS (ELEVATORS) ESCALATORS
•closed cabins inside vertical shafts that
are used to transport people between
different floors in high rise buildings.
•moving stairways that allow people to
move between floors in busy places
such as shopping malls, airports, and
railway stations.
•Lifts are fast and can move up or down
at great speeds….vertical movement.
•These are slow moving…..horizontal &
incline movement.
•move up or down using counterweights
or traction cables.
•The steps of are fixed and linked
together and move up but come down
from behind on a conveyor belt that is
driven by a motor.
•Less space is used for its construction
as the elevator is limited to the shaft &
machine room, which connects all the
floors.
•Space used is same as the staircases
& connects 2 floors .

Difference between Lifts & Escalators
LIFTS ESCALATORS
•Limited number of people can
accommodate at a time.
•There is no waiting period as one can
set foot anytime to climb up or come
down.
•If there is electricity cut-outs then it
doesn’t work.
•Its very versatile, if there is electric cut-
outs then one can climb those steps,
which acts like a staircase.
•Schindler
•Otis
•Fujitec
•Kinetic
•Express
•Noble
•Omega
Different
Companies

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