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Floor Selector abandoned

An abandoned "carriage" selector.

A selector (sometimes referred to as a floor selector, or an elevator leveling cam) is a mechanical device that shows the position of the elevator car in the shaft using electric circuit and without memory. Mechanical selectors were common in relay-driven elevators installed before around 1985. These devices are found in the elevator machine room and are only found in traction elevators. This device on older elevators is currently being replaced with magnetic switches, or proximity sensors (usually a set of vane sensors), or even a Tape Head for the car top and limit switches in the top and bottom of the shaft (with microprocessor controller).

Overview

Typically, an elevator selector consists of multiple switches and a moving carriage.

"Carriage" or "wheel" design

The carriage or wheel moves up and down with the help of a special chain or tape (or commonly known as selector tape in the elevator industry) attached on the carriage and the elevator car. This chain or tape creates a continuous loop in the shaft and it is moved by a wheel on the selector. As the car moves up and down, so does the carriage, and this carriage activates multiple switches inside the selector (to scale) which activates floor position indicator lamps (both inside and outside) and other switches. These switches are connected to the relay-powered controller.

These types of selector may cause some leveling error when the elevator car stopped at the landing. The solution of this problem will be resolved by both "inch up" and "inch down" buttons.

"Screw drive" or "rotating cam" design

The screw drive or rotating cam usually works with vane sensors installed on the elevator car top. To receive the signal from the elevator car top to the controller, the selector will move up and down when the sensors triggered by the metal plate installed among with the guide rails. These power either a motor or electromagnetic switches, and the platform flips switches (not to scale) to a different position.

These types of selector may cause some positioning errors when the elevator car stopped at the landing. The solution of this problem will be resolved by sending the elevator to either the top or bottom serving floor.

Selector design by elevator manufacturers

Each elevator manufacturers creates their own design of selector.

Armor

This selector has a wheel, with teeth on it. There is something next to the wheel, which might keep it aligned to one of the positions for the floors. There are 2 mechanisms, with electromagnets, that advance the wheel to the next position, in either direction. There are most likely contacts/switches on the back of the selector, and a bar attached to the wheel by an axle that touches those contacts/switches.

Dover

Type 1

This type of Dover selector appears to be a vertical bar selector.

Type 2

This type of Dover selector has a rotating disk design, though it appears that there are sensors that detect the disks, instead of contacts, and it is horizontal.

Express Lift

AC single speed (AC/1)/two speed (AC/2)

The Express Lift selector design from the UK for AC-powered elevators is a rotating cam design. In the elevator shaft there are vanes mounted on the guiderails of each floors. These vanes are activated by a vane sensor on the top of the elevator car (which near the modern design). Once each vanes are contacted each other, they activates electromagnetic switches on the controllers and thus rotates the selector cam.

DC

Main article: Express Lift DMR Control

The selector used in Express Lift DMR (DC traction) elevators consists of a large cabinet with two small moving carriages (which represents the elevator car) fixed in a rail inside the cabinet. On the top of the cabinet there is a very small motor which lifts these small carriages.

GAL

This selector is a vertical bar selector.

Montgomery

This selector has a platform that moves up and down. It appears that there are switches, that get flipped when the platform passes by them, and the switches would be in different positions depending on what floor the elevator is on.

Otis

Circa 1920s and earlier

Video of circa 1920s or older Otis selector

Circa 1930s-circa 1970s

The selector design used on some old Otis elevators in the 1960s-1980s is a rotating copper disc design with vertical bar on the back, for DC elevators. Another Otis design in the same era, which might not have existed in the United States is only a vertical bar design, for AC elevators.

Schindler

Unlike many manufacturers, Schindler used a selector that is round like a wheel, and rotates to the left and right. For this design, the elevator car is attached to a cable which turns a big drum on the back of the selector. On the outside of the selector wheel are switches which activates floor position indicator lamps, start/slow down switch, and other switches.

Staley

This selector has a wheel, with teeth on it. There might be a mechanism behind the wheel, which might keep it aligned to one of the positions for the floors. There are 2 mechanisms, with electromagnets, that advance the wheel to the next position, in either direction. There are most likely contacts/switches on the back of the selector, and a bar attached to the wheel by an axle that touches those contacts/switches.

Watson

This selector has a platform that moves up and down, most likely with a screw drive mechanism, and the platform flips switches to a different position, depending on if the elevator is above, or below that floor.

Westinghouse

This selector has a part that moves up and down, which presses switches. The part that moves up and down moves in steps. It moves after the elevator goes up, or down 1 floor.

Unknown

Unknown selector 3 Unknown selector 4 (Otis?) Unknown selector 5 (similar to 3)

Selectors from other manufacturers

Videos

See also

Schindler lifts (Dewhurst fixtures 2) "This elevator only serves two floors."
This article is a stub. You can help Elevatorpedia by expanding it.



Elevator 

Drive systems: Traction • Hydraulic


Types of elevators: Double DeckDumbwaiterFireman'sFreightIncline • PassengerResidentialWheelchair lift


Concept: Destination dispatchElevator algorithm • Elevator control systemElevator machine room • Elevator maintenanceElevator major alterationsElevator modernizationMachine room less elevator


Elevator systems, controllers and equipments: Elevator fixtures • Elevator keys • Elevator special modesElevator doorsDoor camDoor interlocks (Interlock wiring communication system) • Door restrictorElevator Inspection CertificateEmergency stop buttonFloor designatorsGate switch • Old Deadman controls • Overspeed governorMotor-generator set & Silicon-controlled rectifier (for DC-powered elevators) • Insulated-gate bipolar transistor (for AC-VVVF-powered elevators) • Regenerative converter (for AC-VVVF-powered elevators)


See also: List of elevator fixtures guide • List of elevator and escalator companies • Elevator door sill guide (Generic elevator component door sill guide) • Floor numbering (Unlucky floor numbers) • Elevator incidents and accidents

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