Otis Elevator HydroFit Instruction Manual

Owner’s Information Manual
HydroFit Elevators
Otis Elevator Company

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HYDROFIT™Owner’s Information Manual
Publisher: Technical Publications Department, Otis Elevator Company
Registered Trademarks, Registered Service marks, and Unregistered Marks are used within this publication—
where applicable—to properly honor the claims of all companies.
This publication is intended for those individuals or organizations in ownership of HydroFit elevator system and
equipment manufactured and sold by Otis Elevator Company. It is expressly designed to be informative and to
offer a limited understanding of the operation of these systems. It is not intended to be a guide for servicing or
repairing or installing elevator equipment. Professional providers of those services should be contacted to
perform any work in a safe and professional manner.
Any unauthorized reproduction, public display, or distribution of copies by any person of any portion of this
publication may be a violation of Copyright Law of the United States of America and other countries and could
result in the awarding of Statutory Damages of up to $250,000 (US dollars) (17USC504) for infringement, and
may result in further civil and criminal penalties.
Permission to use any portion of this publication should be addressed to:
Otis Elevator Company
Manager, Technical Publications
Otis Service Center
212 West Newberry Road
Bloomfield, CT 06002 USA
Copyright ©2004, 2007, 2009, 2012 Otis Elevator Company. All rights reserved.

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HYDROFIT™Owner’s Information Manual
Owner’s Information Manual
Table of Contents
Preface........................................................................................................................... i
Chapter 1: About Otis Elevator .................................................................................... 1
Chapter 2: Performance and Safety........................................................................... 11
Chapter 3: Your HydroFit Elevator............................................................................. 14
Chapter 4: Maintaining Your HydroFit Elevator.......................................................... 43
Chapter 5: Otis Maintenance and Service ................................................................. 53

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HYDROFIT™Owner’s Information Manual
Preface
Thank you for your recent purchase of the Otis Elevator HydroFit™system.
Your new HydroFit system meets the highest safety and performance standards
available in the market today.
Otis has built a reputation based on quality, reliability and an OSHA-proven record of
safety that’s the best in the business. We continue to pursue a policy of innovation
to ensure our customers receive the highest level of service in the industry. We look
forward to the opportunity to continue to serve you and your elevator needs for years
to come.
The information in this book will provide you and your staff with information about the
Otis Elevator Company, the HydroFit system and its maintenance requirements.
Otis personnel have access to the latest information in support of our maintenance
practices. We continuously look for ways to improve our processes; not only in
support of your equipment, but in the ways we deliver information throughout our
company.
To learn more about what genuine Otis maintenance can mean for you and your
business, or to locate the Otis representative nearest you, please visit our website at
www.otis.com.
How This Book Is Organized
This Owner’s Information Manual is divided into five chapters.
The first chapter gives a history of Otis Elevator Company.
Chapter 2 is designed to make elevator owners more aware of their responsibilities,
including passenger safety, code requirements, and emergency procedures. It also
explains how Otis emphasizes safety in its everyday operations.
Chapter 3 provides information about how your HydroFit elevator operates, a
description of its major components, and available features.
Chapter 4 describes the necessary maintenance needed on your new system.
Chapter 5 contains information about Otis’ service and maintenance programs.

HYDROFIT™Owner’s Information Manual
Use of Warnings
It is e
ssential that you realize your Otis elevator is a complex piece of machinery and
should be serviced only by a trained, authorized elevator mechanic. Tampering with
the equipment is hazardous to you, to the person performing maintenance, to the
passengers,
and may be detrimental to the elevator itself.
Some of the topics in this manual deal with the inherent dangers of elevator
operation, whether electrical, mechanical, or otherwise. These are identified by
warning symbols placed near the application parag
dangers include electrical shock from high voltage, crushing hazards, and flammable
or combustible materials. Additionally, other symbols are used to reflect important
information. The symbols used in this manual are:
Plea
se contact your nearest Otis office if you have any question or require
assistance with your elevator equipment.
HYDROFIT™Owner’s Information Manual
ssential that you realize your Otis elevator is a complex piece of machinery and
should be serviced only by a trained, authorized elevator mechanic. Tampering with
the equipment is hazardous to you, to the person performing maintenance, to the
and may be detrimental to the elevator itself.
Some of the topics in this manual deal with the inherent dangers of elevator
operation, whether electrical, mechanical, or otherwise. These are identified by
warning symbols placed near the application parag
raphs. Some of the potential
dangers include electrical shock from high voltage, crushing hazards, and flammable
or combustible materials. Additionally, other symbols are used to reflect important
information. The symbols used in this manual are:
se contact your nearest Otis office if you have any question or require
assistance with your elevator equipment.
ii
ssential that you realize your Otis elevator is a complex piece of machinery and
should be serviced only by a trained, authorized elevator mechanic. Tampering with
the equipment is hazardous to you, to the person performing maintenance, to the
Some of the topics in this manual deal with the inherent dangers of elevator
operation, whether electrical, mechanical, or otherwise. These are identified by
raphs. Some of the potential
dangers include electrical shock from high voltage, crushing hazards, and flammable
or combustible materials. Additionally, other symbols are used to reflect important
se contact your nearest Otis office if you have any question or require

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Chapter 1: About Otis Elevator
Otis Elevator Company has a long and interesting history that began in the mid-
nineteenth century with its founder, Elisha Graves Otis.
In 1852, while employed by the Yonkers Bedstead Manufacturing Company in
Yonkers, New York, Otis built a hoisting machine with a safety mechanism that
prevented the platform from falling if the hoisting rope broke. The following year, he
opened his own shop in Yonkers, called Union Elevator Works.
It was at the 1854 New York World’s Fair—also known as the Exhibition of the
Industry of All Nations—that Otis introduced his first safety hoist to the public. His
demonstration of riding up and down on the platform and cutting the hoisting rope
without plummeting to the ground attracted huge crowds. The event became
famous and the safety hoist’s debut was a resounding success.
1854: Safety Hoist Elevator at the Crystal Palace, New York World’s Fair
Elevators during the 1850s were used to
hoist freight, and Otis and his sons sold
their product on the existing market as a
hoist. He also realized the safety
mechanism made it possible to safely
carry passengers, thus potentially opening
up a whole new market. 1854: E.G. Otis Calling Card

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
The next problem to overcome was
development of a power source to run
passenger elevators. Factories and
warehouses with freight elevators were
near water, but passenger elevators would
be installed in stores, office buildings, and
hotels, away from any central power source
(this was 22 years before the opening of
the first U.S. electric power station).
Otis’ solution was to invent a small,
oscillating steam engine to power each
elevator. So in 1857, he designed, built,
and installed the first Otis safety passenger
elevator, in the E.V. Haughwout Store in
New York City.
1857: The first passenger elevator ever
built was installed in the E.V. Haughwout
Store in New York City
1873: The elevator operator manipulates
the control rope, regulating the direction
and speed of the car.
Elisha Otis was a master mechanic and
engineer. He obtained many patents in the
1850s, including the safety device he
invented in 1852, the oscillating steam
engine, a brake, steam plows, and a rotary
oven for bakeries.
Unfortunately, at the age of 50, Otis died
suddenly during a diphtheria epidemic in
1861. His sons, Charles and Norton, took
over the business and utilized the elevator
expertise their father taught them. They
renamed the company N.P. Otis & Brother,
then in the late 1860s changed it to Otis
Brothers & Company.
Otis Brothers & Co. patented some 53 new
advancements in elevator equipment,
including hoisting apparatus, brakes, steam
hoist, and pulleys. The brothers continued
to use world’s fairs and industrial fairs to
showcase their elevator technology and
create an international market for Otis
elevators.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
An Otis two-cylinder steam elevator machine and platform were exhibited at the
second world’s fair to be held in the U.S., the Centennial Exposition of 1876 in
Philadelphia. Judges commended Otis for its adaptation of the freight hoist to
passenger elevator and for its attention to safety.
Otis elevators were prominently displayed in 1889 at the Universal Exposition in
Paris. The French government built the Eiffel Tower specifically for the world’s fair
and wanted an all-French monument to represent the construction and technological
expertise. But no French company could overcome the structural demands of
putting elevators inside the tower’s curved legs. Otis Elevator successfully installed
elevators, giving the company a chance to display its product at the fair’s
centerpiece attraction.
Post-Civil War era use of structural steel made it possible to construct taller
buildings. Otis technology kept up with the construction pace during this “Era of the
Skyscraper.”
Otis opened offices in England, France, Canada, Germany, and Belgium, and had
sales agents representing the company throughout the world. Its most famous
elevator installations included the Eiffel Tower, the London Underground, and three
elevators for Russian Emperor Nicholas II’s private quarters in the Kremlin.
1889: Otis Elevators Inside the Curved Legs of the Eiffel Tower

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Modern day Otis came into being during the late 1800s
and the early 1900s, a time when “big business”
flourished. Otis Brothers & Co. merged in 1898 with
several U.S. elevator companies in Boston, Chicago,
and Philadelphia to become the Otis Elevator
Company. Forty more, small, independent elevator
companies were acquired during the period prior to
World War I.
The company expanded its product line by acquiring
the patents for modern escalator technology from
Charles D. Seenberger and Jesse W. Reno. The
world’s leading elevator manufacturer unveiled its new
“escalator” (a term trademarked and owned by Otis for
50 years) at the Paris World’s Fair of 1900.
1920: Freight Incline
1900: Gravity Conveyers
In 1903, Otis introduced what would become the
“backbone” of the elevator industry, the gearless traction
electric elevator. It could be used in buildings of any height
and operated at greater speeds than steam elevators.
As skyscrapers got taller and taller, more Otis elevators
were installed, particularly in New York City. For example,
the 20-story Flatiron building was built in 1902 and had six
Otis elevators. In 1912, the Woolworth building rose to 60
floors and was equipped with 26 elevators.
Skyscrapers reached a new pinnacle in 1931 when the
world’s tallest building—the Empire State Building—
opened, serviced by 67 Otis elevators.
More tall buildings meant more elevators and a greater
need to keep them in good running condition. Otis
recognized this and in 1921 introduced the first preventive
maintenance service. Today, maintenance represents 50
percent of Otis’ overall business.
From its early days under Elisha Otis until late 1960s, Otis
Elevator explored many different product lines outside its
core business of elevators and escalators: the rotary oven
for bakeries in the 1850s, a haymaker in the 1870s, gravity
conveyors around 1900, the Sultan automobile from
1909–1912, and passenger and freight inclines in the
1920–1930s.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Otis converted to military production during World War I, World War II, and the
Korean War. It manufactured crank cases for fighter planes, anti-aircraft guns,
ammunition hoists, gun recoil mechanisms, depth charge throwers, and airplane
elevators for aircraft carriers.
The wars disrupted the normal production, but they also
changed Otis’ business. Automatic elevators have been
sold to homeowners since the 1890s, while most public
buildings used elevator operators to run elevators well
into the 1940s. But labor shortages during World War II
brought the need for automated public elevators to the
forefront. So, in 1950 the first group of Otis automatic
elevators was installed in Texas. 1921: Preventive
Maintenance
1969: Electric Cart
Following the Korean War, Otis continued to
diversify its product line, producing military
electronics, material handling equipment,
and automatic bowling pinsetters. One of its
more unique operations was the
manufacture of electric buses, vans, and
golf carts.
1969: Electric Golf Cart
By the late 1960s and early 1970s, Otis
officials chose to concentrate on the core
elevator and escalator business and
divested the company’s other holdings.
United Technologies purchased the Otis Elevator Company in 1975. Otis became a
wholly owned subsidiary in 1976.
One of the most significant developments in elevator technology was the use of
computer chips to make elevator control decisions. Prior to this development,
elevators relied on large collections of relays and switches. These relay-based
systems required a lot more maintenance and occupied significant space.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
In the early 1980s, Otis developed the first microprocessor control elevator system,
called the Elevonic®101. It was a watershed event and paved the way for future
developments utilizing computer technology.
Advances in microprocessor and data communications technology led to Otis’ first
Remote Elevator Monitoring (REM®) system, which was introduced in 1985 and
installed at an Otis elevator site in the United Kingdom.
REM systems monitor elevators 24 hours a day and provide diagnostic information
via a telephone line to our technical center. This information assists our technicians
in preventing elevator disruptions.
1985: Remote Elevator Monitoring (REM®) systems monitor elevators 24 hours a day.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Another important technological advance—the Elevonic®411 software based control
system—was released by Otis in 1990. These sophisticated Elevonic systems
made “real-time” dispatching rules based on changing traffic conditions in a building.
They also managed elevator ride quality, energy consumption, motor performance,
and all the in-car information displays.
Elevonic Hall Position
Indicator 1990: Elevonic®Hall Button

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Some other Otis products include:
Gen2™Elevator System: The first major breakthrough in elevator lifting
technology in nearly 150 years. Gen2, an elevator system for low- and mid-
rise buildings, is the first to use flat coated steel belts to lift the elevator cars.
The belts are 1 in. (25 mm) wide and 0.1 in. (2.5 mm) thick, quieter, lighter,
easily bend around a 4 in. (101 mm) diameter sheave, and last up to two to
three times longer than traditional steel ropes. That means the Gen2 system
requires a machine one-quarter the size of a traditional machine, eliminating
the need for a separate machine room.
TRAV-O-LATOR®: Moving walkways for expansive facilities such as airport
terminals and shopping centers.
1996: TRAV-O-LATOR®
Otis is focused on advanced technology that will improve its operations and products
in three key areas: quality, efficiency, and safety. For example:
Otis dispatching technology improves service dramatically by analyzing and
adapting to a building’s traffic pattern, then assigning elevators to respond to
variations in passenger traffic within the building. This is critical to an
integrated building transit system because traffic patterns in the buildings of
the future will be more complex than in today’s buildings.
Otis engineers are also designing sophisticated remote elevator monitoring
systems. The more closely an elevator is monitored, the easier it can be
maintained with fewer costly shutdowns.

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HYDROFIT™Owner’s Information Manual
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Elevator monitoring systems provide comprehensive information about elevator condition,
status, and performance.
Today, Otis is recognized as the elevator industry leader, maintaining more than 1.7
million elevators and escalators worldwide. It is an $11.6 billion (U.S. dollars)
company with 60,000 employees.

HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this
Chapter 2: Performance and Safety
If anything improper is discovered, corrective action must be taken
immediately. Do not attempt to repair the equipment. For safety
reasons, only a trained, authorized elevator mechanic should ever
service you
Knowing what to look for is probably the most important aspect of elevator
awareness. When you know how to spot issues in performance, you can influence
the efficiency of your equipment by taking care of issues before they become
problems.
The following information suggests ways you can look after your
investment and help keep it running at optimum performance. More information
about general maintenance procedures can be found in Chapter 4.
You or a member of your building staff should go t
regularly with each elevator car:
Emergency Lighting/Alarm Bell
system provides passenger
reassurance in emergencies
You should be aware of several things in ord
potential hazards. The following seven
be applied on a regular basis to most elevator systems.

How long must passengers wait for an elevator at the lobby?
Well-timed arrival
s and departures, as well as proper acceleration and deceleration,
are critical to fast, efficient service.
HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this
work is defined in the legend upon the front page hereof.
Chapter 2: Performance and Safety
If anything improper is discovered, corrective action must be taken
immediately. Do not attempt to repair the equipment. For safety
reasons, only a trained, authorized elevator mechanic should ever
service you
r elevator.
Knowing what to look for is probably the most important aspect of elevator
awareness. When you know how to spot issues in performance, you can influence
the efficiency of your equipment by taking care of issues before they become
The following information suggests ways you can look after your
investment and help keep it running at optimum performance. More information
about general maintenance procedures can be found in Chapter 4.
You or a member of your building staff should go t
hrough the following procedures
regularly with each elevator car:
Emergency Lighting/Alarm Bell
system provides passenger
reassurance in emergencies
1. Test the operations and safety devices
Test alarm bells, stop switches,
intercoms, telephone
connections, and
emergency lighting systems to make sure
they will work in an emergency.
2. Ride the elevators.
Ride the elevator and pay attention to the
smoothness of starting and stopping, to
any unusual sounds (such as squeaks or
scrapes), and to any
unusual movements,
vibrations, or odors. Close your eyes to
increase awareness of irregularities.
3. Listen during rush hours.
Stand in the lobby during peak traffic
periods listening to passengers'
comments.
You should be aware of several things in ord
er to prevent equipment failure and/or
potential hazards. The following seven
-
point safety and performance checklist can
be applied on a regular basis to most elevator systems.
How long must passengers wait for an elevator at the lobby?
s and departures, as well as proper acceleration and deceleration,
are critical to fast, efficient service.
10
work is defined in the legend upon the front page hereof.
If anything improper is discovered, corrective action must be taken
immediately. Do not attempt to repair the equipment. For safety
reasons, only a trained, authorized elevator mechanic should ever
Knowing what to look for is probably the most important aspect of elevator
awareness. When you know how to spot issues in performance, you can influence
the efficiency of your equipment by taking care of issues before they become
The following information suggests ways you can look after your
investment and help keep it running at optimum performance. More information
hrough the following procedures
1. Test the operations and safety devices
.
Test alarm bells, stop switches,
connections, and
emergency lighting systems to make sure
they will work in an emergency.
Ride the elevator and pay attention to the
smoothness of starting and stopping, to
any unusual sounds (such as squeaks or
unusual movements,
vibrations, or odors. Close your eyes to
increase awareness of irregularities.
3. Listen during rush hours.
Stand in the lobby during peak traffic
periods listening to passengers'
er to prevent equipment failure and/or
point safety and performance checklist can
How long must passengers wait for an elevator at the lobby?
s and departures, as well as proper acceleration and deceleration,

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Do the passengers have enough time to enter and exit before the
doors close?
There are a number of variables that determine the door’s opening cycle. The
minimum time may depend on the number of elevators in the bank and on the
distance from a point in the center of the lobby to each elevator. Time may also be
measured from notification that a car is arriving by a lantern and audible signal.
Times might also be longer for elevators that service elderly or disabled persons.
Do the doors reverse direction without
touching passengers?
Your elevator is equipped with an
electronic detector to sense passengers in
the door zone. This detector enables a
closing door to reverse direction without
touching passengers. Reversal should
take place as soon as any portion of the
passenger enters the door zone when the
doors have begun to close.
Does the car stop level with the hall
floor?
Leveling is the process of the elevator
platform attaining a stop position that is
even with the landing. The car should
stop within +/- 0.2 in. (+/-5 mm) of the hall
floor, and leveling should be consistent
whether the car is full or empty.
Electronic detectors enable a
closing door to reverse direction
without touching passengers.
Does the alarm bell work?
The alarm bell should be tested once a week by pressing the alarm button on
the car operating panel. This quick and simple procedure ensures that the
bell will work when and if it is needed.
Door Open Button Alarm Bell Stop Switch
Is the intercom or telephone in good working order?
Intercoms and telephones should be tested regularly. Passengers can be spared
inconvenience when minor mechanical difficulties occur by following instructions
received over the intercom or telephone. During an emergency, communication

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
with passengers helps to alleviate or avert panic. At these times, information
from passengers can be of great assistance to emergency personnel.
Is the interior of the elevator adequately lit?
Check that all light switches are on, all lamps are lit, and all light diffusers are
clean to permit maximum transmission of light.
Only use the elevator for the purposes for which it was designed. The elevator has
been designed to transport passengers and goods within a building, carrying loads
up to the maximum weight indicated inside the elevator car, running at the speed for
a rated traffic condition. Overloading will result in visual and/or audible signals in the
car and further movements will be prevented until the overload condition has
disappeared.
It is extremely important that planned maintenance be recorded with a reputable
maintenance company. Maintenance is necessary to ensure the safe and correct
operation of the equipment. Inspections of the equipment should be carried out in
accordance with local regulations. Any irregularities in the operation or performance
of the elevator should be reported to the elevator maintenance company
immediately. Any alterations or changes to the building that may affect the elevator
should also be discussed with the maintenance company.
The control room and access areas for servicing the elevator equipment should
remain clean and free of debris at all times. For proper operation, the control room
temperature must be between 32° F (0° C) and 104° F (40° C). Areas subject to
excessive heat must have proper ventilation.
The elevator’s two-way voice communication system must be kept in good working
order. This includes the communication line between the car and a rescue service.
State-of-the-art elevator and escalator engineering has developed mechanisms that
greatly reduce the risks to life and property in emergency situations. However,
building personnel still play a vital role in directing occupants to safety, in monitoring
equipment, and in operating controls that initiate emergency routines.
The proper handling of elevators and escalators in an emergency could mean the
difference between life and death. You should ensure that all your building
personnel are familiar with emergency procedures suitable to your building structure
and all of its equipment in the event of accidents, fire, earthquake, or power failure.
Contact your local authorities and fire department for appropriate advice,
inspections, and drills.
Fireman’s Service—SES
Fire service varies based on local code requirements. Contact your local authorities
and fire department for appropriate advice, inspections, and drills.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Firemen’s Service/Special Emergency Service allows control of elevator operation in
the event of fire or other time-sensitive emergencies, particularly where immediate
access to specific building areas or floors is necessary. Fireman’s Service has two
separate operations, or phases.
Firefighter’s Service Phase 1
When a smoke or heat sensor is activated on any level (except the main fire return
floor), a signal is sent to the elevator control system to return the elevator to the
main fire return floor or main designated return landing. The elevator then proceeds
immediately to this landing and parks with the door open.
If a smoke or heat sensor is activated at the main fire return floor, the elevator is
placed in a “fire recall” status; however, the elevator will proceed to the alternate fire
return floor, and park with the door open.
Firefighter’s Service Phase 2
This feature is activated by the fire fighters using a keyswitch in the car, which
places the elevator under their control. This feature includes the call cancel button
and keyswitch in car. When the call cancel button is activated, all registered calls
are cancelled and the car stops at the next landing.
Emergency Power Option
In the event of a power failure, your building’s emergency power supply operates the
elevator during the failure, but only if you have selected the Emergency Power
Option for your elevators.
If your elevator system's Emergency Power Option is set to the AUTO mode, each
car will automatically travel directly to the lobby (or the previously designated floor)
and the doors will open to allow passengers to exit. After the cars arrive at the
lobby, they remain parked there until one or more cars are selected to provide
service under Emergency Power.
If your elevator system's Emergency Power Option does not have an AUTO mode,
or if that mode is not turned on, the cars may be brought to the lobby by manually
selecting them, one at a time, using the emergency power strip switch.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Chapter 3: Your HydroFit™/HydroAccel Elevator
Introduction
Today's elevators provide a safe, rapid means of passenger transportation. In large part,
this is due to advances in elevator technology. The intent of the information presented
here is to provide you with a general understanding of how your HydroFit™/HydroAccel
elevator system is designed and how it operates.
The HydroFit™has both a machine room (MR) and a machine-roomless (MRL)
application. The machine-roomless requires no machine room everything “Fits” inside a
hoistway, as seen in the picture below. HydroAccel has a machine room (MR)
application also.

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HYDROFIT™Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Elevator Operation
In order to gain further understanding of how a HydroFit™/HydroAccel elevator system
works, let’s take you through a typical sequence of operation. A passenger registering an
elevator call sets into motion a series of actions. The signal is first picked up by the
controller, which acknowledges the request by illuminating an indicator on or near the call
button. Also placed into memory is the location of the call for pickup or delivery. All hall
calls are sent to all elevators, if part of a group. (Multiple elevators within a building are
referred to as a “group” of elevators.) Each elevator in the group calculates its response
time to the call and the elevator with the shortest response time is dispatched to pick up
the passenger. The elevator checks itself against a preflight checklist before permission
to run is given. Of particular importance is determining the integrity of the elevator’s
safety related devices prior to starting the run. In addition, the elevator contains a safety
chain to prohibit elevator motion in response to an unsafe condition. The safety chain
consists of electronic and electromechanical switches placed at strategic locations in the
elevator system. Connected in series, they act as a safety circuit ensuring various
elevator apparatus are in the correct operating state for the elevator to make a run. Any
one device not in its expected state breaks the chain and the elevator does not operate.
An emergency stop is initiated whenever a safety chain device “opens” while the elevator
is in motion. When the controller (the brain of the elevator) receives a request for
service, it reviews a sequence of questions and issues instructions according to the
responses. Controller Sequence of Questions
Where do I need to send the elevator?
What is the weight in the car?
Is it safe to move the elevator?
While I’m moving, how do I know where I am in the hoistway?
How do I stop once I’ve reached the destination?
What do I do after I’ve stopped?
The Controller now has instructions to move the elevator car in response to the
passenger call and has completed its safety check confirming that the elevator is safe to
move. It then sends instructions to the elevator control circuits telling the elevator car
which direction to move.