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Chapter 11. Elevator System Control Devices and Applications. Elevator Systems • Conveyance • Calls • Access • Special Operating Modes • Elevator System Control Devices • Elevator System Control Applications.
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Chapter 11 Elevator System Control Devices and Applications Elevator Systems • Conveyance • Calls • Access • Special Operating Modes • Elevator System Control Devices • Elevator System Control Applications
Conveying systems include systems to automatically transport people and/or materials between areas of a building.
While passenger elevators are the most common type of elevator, other types of elevators are specifically designed for other functions.
Traction elevators are raised and lowered through the elevator shaft by cables operated by electric motors.
Most of the equipment needed to operate a traction elevator is located in a machine room above the elevator shaft.
Machine room-less elevators use a design that reduces the size of the traction equipment enough so that it does not require a machine room.
Hydraulic elevators are raised and lowered by pistons filled with fluid.
Holeless elevators reconfigure the hydraulic pistons to the side of the elevator, reducing the amount of equipment space needed directly beneath the elevator shaft.
The governor sheave engages the emergency brake system if the elevator falls too rapidly.
When engaged, emergency elevator brakes wedge up against the rails guiding the elevator car, slowing it to a stop.
When the elevator car is in the correct position, the door operating system unlocks and pulls open both the car doors and the elevator shaft doors.
The elevator system can respond to signals from other building systems to add calls, control access, and change elevator operating modes.
The normal operating algorithm of an elevator system determines the best sequence of stops in order to minimize passengers’ waiting time.
Elevators can be used to control access to certain areas of a building by either controlling the access to the elevator or controlling where the elevator can stop.
Some special elevator operating modes help the elevator system serve passengers more efficiently during certain periods of the day.
Phase two fire service mode functions are activated by a keyswitch, typically inside the elevator car.
Elevator controllers are connected to numerous elevator-specific control devices to operate the elevator system independently.
Call buttons are the typical method for passengers to select their desired travel direction or floor.
Telephones or similar two-way communication devices are installed inside elevator carsfor emergencies.
In emergency fire situations, the fire alarm control panel signals to the elevator controller to recall the elevator car(s) to a designated floor.
Inputs from access control systems can be used by elevator controllers to anticipate waiting passengers and automatically call elevators to certain floors.
Access control systems can be used to admit only authorized personnel to elevators serving secure building areas.
When integrated with access control systems, elevators can be used to secure individual building floors by requiring authorization for certain floor calls from inside the elevator car.