BUILDING SERVICES TWO (BLD60503)
Vertical Transportation System
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Having completed this lecture, you should be able to:Type - State the reasons for selecting a particular
type of lift or escalator installation Location - Appreciate the need for careful
location of lift and escalator installationsControl system - Outline the various methods of
control associated with lifts.Describe the builders’ work associated with lift
shafts and escalators
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Category of Vertical Transportationo Vertical Lifts or elevatorso Escalators or moving staircaseso Travelators or moving walkways
Services above mainly associated with human activity or goods under specific control.
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Forms of mechanical transportation:
Lifts Escalator Travelator
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemPrimary reasons for the use of this transportation
1. High rise buildings require rapid vertical transportation- More offices or residential can be built.
2. Greater levels of expectation – Life still goes on without the options but life would be easier with them.
3. Lift shaft takes up less space than staircase – lettable or usable space increased.
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Selection of LiftSelection of location & number of lifts owes more to natural than mechanical sciences
Ergonomics (comfort design)Social behaviourPsychology
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Location of LiftLift should be located centrally within a
building taking into account:o Proximity of entrances and exitso Intended ingress and egress routeso Staircaseso Allowing the use of whole day
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Groupingo Clustered or group around a nucleus
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Groupingo Clustered or group around a nucleus
Advantageo Best standing position.o Reduce waiting timeo Cost of installation reduced
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Other grouping Special purpose:
oGoods lift located close to production.oHospitals – Lift for emergency useoShopping malls – Lift at both ends,
Escalators at centre
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Number of Lifts Main considerations
1. Population of building & ingress and egress times.
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Number of Lifts2. Quality of service required (waiting time)
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Number of Lifts3. Numbers of floors served & height of
building 4. Type of building occupancy5.Specialist services within building – transport delicate instrument & equipment 6.Relation of the building with external public transport services
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Number of Lifts
Which is better?To have a several small lifts or fewer large
lifts? (Assuming overall carrying capacity
remains the same)
Answer: Several small lifts
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemRound trip time (RTT)
An acceptable method for estimating and comparing efficiency and effectiveness of
lift installation is obtained by calculating the round trip time (RTT)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemRound trip time (RTT)
• Loading and unloading time• Opening and closing time including
holding time• Acceleration & deceleration at
landings• Operating velocity
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemRound trip time (RTT)
Work example.A building having five floors at 3m floor to floor spacing, a car capacity of six persons and 2m/s speed of travel:
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemRound trip time (RTT)
1. Probable number of stops (S1)S1 = S – S[(S – 1)/S)]ⁿWhere S = maximum number of stops n = number of people or car capacity
S₁ = 4 – 4 [(4-1)/4]⁶
= 3.3 stops (3 stops)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
2. Upward journey time (Tᵤ)Tᵤ = S₁ [(L/SV) + 2V]
Where L = lift travel, 4 x 3 m = 12m V = car speed, 2 m/s
Tᵤ = 3[(12/4x2] + 2(2)] = 16.5s
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
3. Downward journey time (Td)Td = L/V + 2V
= 12/2 + 2(2)= 10s
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
4. Passenger transfer time (Tp). Allow 2–3s per person,
At 2s; Tp = 2n= 2 x 6 = 12s
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
5. Door opening time (Tₒ) Assume door speed (Vd)= 0.5m/s and door width (W) = 1.2m;
Tₒ = 2(S₁ + 1) W/Vd
= 2(3 + 1) 1.2/0.5 = 19.2s
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System6. Round trip time (RTT)
RTT = Tᵤ+ Td+ Tp + Tₒ = 16.5 + 10 + 12 + 19.2 = 57.7s
Notes:1. These calculations assume the lift deposits passengers
in one direction only and then returns.2. Allowance not made for downward stops, passengers
transfer and door operating times3. If a group of lifts is being considered, the RTT is
calculated by dividing by the number in the group.
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Design & Mechanics of Electric Lift
BUILDING | SERVICES | TWO (BLD60503)Vertical Transportation System
Electric Lifts Components (Traction driven):
Lift car Steel cable Driving sheave Counterweight
Load on motor = weight of car + its load + friction – counterweight (=about half car load)
BUILDING | SERVICES | TWO (BLD60503)
BUILDING | SERVICES | TWO (BLD60503)
BUILDING | SERVICES | TWO (BLD60503)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemElectric Lifts - Principles of Operation
Counterweight reduces load on electric motor.
Load on motor = weight of car + its load + friction – counterweight (=about half car load)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemMotor set
Geared type – drive is transmit through a worm gear.
Gearless type – direct coupling from motor to driving sheave.
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemMotor set
Geared type – drive is transmit through a worm gear.
BUILDING | SERVICES | TWO (BLD60503)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemMotor set
Gearless type – direct coupling from motor to driving sheave.
BUILDING | SERVICES | TWO (BLD60503)
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Main requirements of a Lift Motor:
High starting torqueLow kinetic energyQuietness
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Powered by direct current (DC) generator with variable output due to greater accuracy in use than Alternating Current (AC) variations. Floor levelling Smoother ride
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
DC motor preferred More durable in resisting variable demands Frequent stopping and starting.
Combination of AC & DC Traction sheave by AC Brakes & reduction gearing by DC
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Car speed up to .05m/s : 3 phase AC motors is used.
Car speed between 0.5m/s to 1.25m/s: a two speed motor • for quick inter floor travel and • low landing speeds for
comfort.
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Above 1.5m/s – DC motors is used.
Advent of modern electronics, standard AC motors speed is controlled using static frequency converters.
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemAC induction motor
Induction motorhttps://youtu.be/HWrNzUCjbkk
DC Induction motorhttps://youtu.be/LAtPHANEfQo
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Roping Arrangements
Two principal methods of drive for lifts:1.Drum drive2.Traction drive
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemDrum drive
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation SystemTraction Drive (Sheave drive)
a. Single wrap tractionb. Double wrap traction
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation
System
Roping arrangements
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation
System
Roping arrangements
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation
System
Roping arrangements
BUILDING | SERVICES | TWO (BLD60503)Vertical
Transportation System
Roping arrangements
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation
SystemRoping arrangements
BUILDING | SERVICES | TWO (BLD60503)
Vertical Transportation System
Roping ArrangementCompensating cables (>10 ten sty high buildings)-Offset load transfer from car to counterweight-Reduce bounce-Pit required-High tensile steel wire (9 to 19mm dia
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System Pulley system
https://youtu.be/aMx7nIIH9ik
https://youtu.be/LiBcur1aqcg
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System
Machine room location On top of lift shaft Arrangement allows min lengths of cable Allows winding gear to be directly in line
with the load
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System
Brakes 2 types of brake; Operational and
emergency Electromagnetic or directly act on
sheave
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System
Operational brake Electromagnetic or directly act on
sheave Mechanically applied but
electromagnetic held off Supply failure will apply the brake
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System Emergency brake Operates directly on the guide rails Consist of a mechanical clamp controlled
by overspeed governor Governor fly weights break electrical
contacts in turn applies mechanical brake
https://youtu.be/57MID7P3xBc
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportatio
n System
Emergency Brake
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportatio
n System
Emergency Brake
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportatio
n System
Emergency Brake
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation
System
Emergency Brake –overspeed governor
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System
How Lift works https://youtu.be/hMdJLXGxynA
BUILDING | SERVICES | TWO (BLD60503/QSB2714)
Vertical Transportation System
The End