History• 236 BC – First Passenger Lift,

Archimedes• 1853 – Safe Elevator Demo,

Elisha Otis• 1857 – First Safe Elevator

Installation, Cooper Union, NYC

• 1861 – Otis Elevator Patent

Otis Patent 1861

History

• 1873 – First Modern DC Motor

• 1874 – J. W. Meaker Door Opener Patent

• 1880 – First Electric Motor Controlled Elevator Siemens / Sprague

• 1882-1889 – Tesla AC Induction Motor 3-Phase Squirrel Cage Design

• 1889 – Otis Elevator Uses DC Motor

Otis DC

Elevator Motor

Circa 1889

History• 1891 – Ward Leonard Variable

Speed Control• AC Induction Motor Turning DC Dynamo• Rheostat to Control Generated Voltage• DC Voltage Controls DC Motor Speed

• 1900-1970’s – Ward-Leonard M-G Sets and DC Motors Used for Variable Speed Elevators

• AC Motors Used 1 and 2 Speed Starters

Otis No. 1 Geared DC Machine with DC Motor

Circa 1915

Otis Gearless DC Machine

Circa 1919

M-G Set Controls (Otis Elevator, 1920’s)

Otis Type 84 26 Broadway,NYC

Circa 1930’s

History

• 1975-Present• Thyristor (SCR) DC Drives

Control Elevators

• All Analog Components in the 70’s

• Replaces Aging M-G Sets

• 1980’s – Microprocessors Improve• Car Dispatch and Motor Drive Controllers

Otis type 84,NYC with Encoder

Westinghouse #205 with Encoder

History

• Late 1980’s – • Variable Frequency Inverters AC Induction Motors,

Geared Applications Only

• Early 1990’s – • More AC Inverters and Motors Begin to Displace

Small DC, 3-15 HP

• Mid-1990’s – • Vector Control AC Inverters 10-40 HP Almost as Good

as SCR-DC. • KONE Introduces PM EcoDisc AC Machine

History

– Custom Gearless AC Induction Machines– First Fully Regenerative AC

Elevator Drives– Much Discussion on PM-AC and MRL– SCR-DC Still Used for Medium and

Large Building Mods

Late 1990’s –

History

– More PM-AC Motor Manufacturers. PM Gearless Begins to Replace AC Geared

– EU Focus on Efficiency and Harmonics/EMC– Lower Cost IGBT Inverter Components– North America Begins to Focus on Energy Reduction– New Construction Leaning toward AC– SCR-DC Still Used on Medium-Large Building Mods

2000-Present –

How The Elevator WorksBy Joseph Mackay Plaxco

The University of the SouthSewanee, TN 37383

Why?

• I find the elevator “cool.”• Phobia when younger• Gets people to destinations fast.• Large cities wouldn’t be the same.

Different Types

• Freight Elevators• Stage Elevators

The Basic Design

• The basic design is a compartment that is somehow lifted• Two Types of Elevators:

• Hydraulic• Rope-Geared

20

Hydraulic Code Changes

Holeless Hydraulic Holed Hydraulic Roped Hydraulic

Hydraulic

Hydraulic Elevator (holed)

Guide Rails

Plunger & Cylinder

Controller & Pumping Unit

To & From Oil PipeHoistway Door

Door Operator

• Rise Limitations: ~ 60 feet• Cost: $35 - $85K• Speeds: 100/125/150 fpm• Advantages:

• low cost• no penthouse• no structural load on building

• Disadvantages• slow• energy inefficient

Hydraulic Elevators - holed

Hydraulic Elevator (holeless)

Controller & Pumping Unit

To & From Oil Pipe

Plungers & Cylinders

Guide Rails

Hoistway Door

Door Operator

Hydraulic Elevators - HolelessHydraulic Elevators - Holeless

• Rise Limitations: 20 feet• Cost: $35 - $45K• Speeds: 100/125 fpm • Advantages:

• no well hole• minimizes environmental contamination

• Disadvantages:• limited travel

Holeless: Roped Hydraulic

Holeless: Roped Hydraulic ElevatorsHoleless: Roped Hydraulic Elevators• Rise Limitations: 60 feet• Cost: $45k - $75k • Speeds: 100 - 125 - 150 fpm• Advantages:

• Eliminates well hole• Same 60’ travel range as “holed” hydro• Existing Building

• Disadvantages• More costly than conventional holed hydraulic

http://www.kone.com/en_US/main/0,,content=59104,00.html

The Hydraulic Elevator

• The car is moved up and down using “a fluid piston mounted inside a cylinder” (Harris).

• Consists of three parts:• Tank • Pump• Valve

Hydraulic ElevatorsA Closer Look

• The car is placed on a piston.• Fluid Pumping System• A tank (off to the side) holds the fluid. • When the valve closes, the car is lifted. • When the valve opens, the car is lowered.

Diagram of Hydraulic Elevator

• The following link is from the website “How Stuff Works” written by Tom Harris.

• How Elevators Work - Hydraulic

Hydraulic Disadvantages

• Two Disadvantages• Must Have Enough Room• Energy Inefficient

Rope-Geared Elevators

• These are the most popular types of elevators. • Rather than being pushed from below, these types of elevators are

moved using cables

Rope-Geared Design

• Cables attach to the car and through a sheave. • The sheave is connected to an electric motor.• Motor turns one way, elevator moves up. Motor turns the other way, elevator

moves down.• The ropes are connected to a counterweight. • The counterweight system serves as a means for conserving energy.

Rope-Geared Design (Cont’d)

• Rails are used to guide the elevator• Keep elevator and counterweights steady.• Rope-geared elevators are much more efficient and safer.

Diagram of Rope-GearedElevator• The following link came from the “How Stuff Works” webpage written

by Tom Harris• Rope-Geared Elevator Diagram

Traction Elevator

Machine

Governor

Controller

Guide Rails

Counterweight

Buffers

Car Frame &Safety

Hoistway Door

Door Operator

25

Traction Changes

Geared Gearless

25

Traction Changes

Geared Gearless

25

Traction Changes

Geared Gearless

Traction ElevatorsTraction Elevators• Rise Limitations: ~ 300 feet (Geared)

unlimited (Gearless)

• Cost: $150,000 - $200,000 (Geared) $200,000 + (Gearless)

• Speeds: 350 - 500 fpm (Geared) 500 - 1800+ (Gearless)

• Advantages of Gearless:• smoother• approx. twice machine life

Otis Gen 2click to play movie

(Traction) Rise Limitation: 300 feet

Safety Systems

• More ropes than needed• Built-in brake systems• Governor prevents the elevator from falling to the bottom of the shaft.

Centrifugal force causes a brake system to activate.• Also has an electromagnetic brake that is activated if the elevator loses power.• Automated Brake System at the top and bottom of the shaft.

Moving To Destinations

• Modern elevators use computers.• Slows down• Only answer “up calls” as going up and the same for going down.• Modern “Smart” systems take into account the busiest parts of the day.• Press the floor you want in the lobby.• Load Sensor

Works Cited

• Harris, Tom. “How Elevators Work”.www.howstuffworks.com/elevator2002.

Elevator Control System

Pontificia Universidad JaverianaJavier Mena

2008

The Elevator Problem

• There is a building of several floors and several elevators.• There are also users that want to use the elevators.

User interaction

• The user can be outside the elevator and waits for the elevator to arrive.

User interaction

• OR the user can be inside the elevator and tells the elevator where he/she wants to go.

User A User C Floor N

Elevator 1

Floor 2 Elevator 2

User B Floor 1 Elevator 3

Controller 1 Controller 2 Controller 3

General View

Component View

User

Floor F

call

The user in the floor F, presses a button to call the elevator

Component View

User

Floor F Elevator L Controller

call

call(F)

arrive(Ack)

Act=unit

step(D)

at(F)

Floor F Doors

startTimer(Millis Ack)

Act=unit

Component View

User

Elevator L

call(F)

The user, inside the elevator L, user presses button to go to Floor F

Component View (Complete)

User

Floor F

User

Elevator L Controller

call call(F)

call(F)

arrive(Ack)

Ack=unit

step(D)

at(F)

Floor F Doors

startTimer(Millis Ack)

Ack=unit

Component View (Complete)

User

Floor F

User

Elevator L Controller

call call(F)

call(F)

arrive(Ack)

Ack=unit

step(D)

at(F)

The controller can handle 2 messages types.Floor F Doors

startTimer(Millis Ack)

Ack=unit

Design of the controllerThe controller represents the logic that controls the movement of the elevators through floors.

The operations of the controller are very basic, it can only turn the engines on/off to move the elevator up or down, just one floor each time.

Each time it arrives to a floor, it notifies the Elevator, which decides what to do.

Design of the controllerThe controller can send 2 messages: starttimer(5000 Tid), tells the engines to turn

on during 5 seconds. at(F) tells the elevator the current location its

current location.

Which are the possible states of the controller?

Design of the controllerThe controller can send 2 messages: starttimer(5000 Tid), tells the engines to turn on

during 5 seconds. at(F) tells the elevator the current location its

current location.

Which are the possible states of the controller? Answer: 2 The controller has the engines turned on The controller has the engines turned off

Design of the controllerIn our design the controller can receive 2 messages: stoptimer: when the engines has been turned off step(Dest): when the elevator wants to go towards a floor

What should we do in each case?Each controller must know the current floor (in real life, through a sensor), and the Elevator

related to the controller.

State diagram for the controller

Design of Floor (1)

User

Floor F

User

Elevator L Controller

call call(F)

call(F)

arrive(Ack)

Ack=unit

step(D)

at(F)

Floor F Doors

startTimer(Millis Ack)

Ack=unit The floor have can receive one message type, but it can have3 internal states:-Doors being opened-Doing nothing at all-Handling a the call of a User

Design of Floor (1)The floor have can receive 2 message types, but it can have3 internal states:

Doors operating (opening and closing) Doing nothing at all Handling a the call of a User

The messages that the floor can receive are: arrive(Ack): an elevator has arrive. The Floor must

open the doors, and then notify through Ack=unit call: is received when the User wants that an elevator

goes to the current floor. stoptimer: when the doors have been opened (and

closed)

Design of Floor (2)

Also the floor can send messages to the elevator: call(F), then wait for the elevator to arrive to the floor.

And the floor can send messages to the doors of the floor: starttimer(5000 Fid): open and close the doors in 5

seconds (it may take more time).

Design of Floor (3)

Analyze the possible states and messages that the Floor can receive/send in each state.

Follow the Main Component diagram.

State Diagram of a Floor

Component View (Complete)

User

Floor F

User

Elevator L Controller

call call(F)

call(F)

arrive(Ack)

Ack=unit

step(D)

at(F)

Floor F Doors

startTimer(Millis Ack)

Ack=unit

Design of Elevator

Analyze the possible states and messages that the Floor can receive/send in each state.

Follow the Main Component diagram.

Elevator State Diagram