CET Elevator key terms

A weighted assembly connected to the car by hoist ropes that balances most of the car's weight, reducing motor effort and providing traction. Its mass typically equals car weight plus about 40 to 50 percent of rated load.

A centrifugal overspeed device mounted in the machine room or overhead that trips a safety mechanism when the car or counterweight exceeds a set speed, gripping a rope to activate the safeties.

Mechanical braking devices mounted on the car or counterweight frame that grip the guide rails to stop and hold the moving unit when the governor trips or the suspension fails.

A hoisting arrangement in which ropes pass over a grooved sheave and lift the car by friction rather than winding on a drum, used in most passenger elevators above low rise.

The grooved driving wheel over which hoist ropes pass. Its groove profile and diameter affect rope life, traction, and the load the machine must move.

Steel wire ropes that suspend the car and counterweight and transmit lifting force. Minimum number and safety factors are specified by code, and they must be inspected for broken wires and wear.

Vertical steel T-section rails fixed to the hoistway that guide the car and counterweight and provide the surface the safeties clamp during an emergency stop.

Sliding or roller assemblies on the car and counterweight that ride the guide rails, keeping travel smooth and aligned while limiting lateral sway.

Any condition in which the car or counterweight travels faster than its designed rated speed, detected by the governor and corrected by tripping the safeties or applying the machine brake.

A spring-applied, electrically released friction brake on the hoisting machine that holds the car at a floor and stops it on loss of power or a fault signal.

The electrical panel that governs elevator operation, sequencing calls, monitoring door and safety circuits, and commanding the drive and brake in response to inputs.

A series loop of normally closed contacts from switches such as door interlocks, governor, pit, and stop switches. Opening any contact removes power and stops the car.

A code-required device that prevents the car from moving unless every hoistway door is closed and locked, and prevents a door from opening unless the car is at that landing.

The motorized mechanism on the car that opens and closes the car door and, through a coupling, drives the landing door, monitored for closing force and obstruction detection.

A floor level where passengers enter or leave the elevator, including the landing door, sill, and call buttons serving that level.

The vertical shaft enclosing the elevator car and counterweight, bounded by walls, with openings at each landing closed by hoistway doors.

The space below the lowest landing in the hoistway, housing buffers, governor tension sheave, and stop and pit switches, accessed only under controlled safety procedures.

A manually operated switch in the pit that removes power from the car and lighting circuits for safe maintenance access, part of the safety circuit.

Energy-absorbing devices in the pit that stop a descending car or counterweight beyond its normal travel, either spring or oil type depending on rated speed.

The maximum load, in kilograms or pounds and often expressed as a number of passengers, for which the elevator is designed and which determines counterweight balance and capacity signage.

The speed at which the elevator is designed to operate under rated load and normal conditions, used as the reference for governor trip settings and buffer selection.

A procedure that isolates and locks all energy sources before maintenance, verifying zero energy, so that equipment cannot be re-energized while a worker is exposed.

The fused or circuit-breaker switch that supplies power to the elevator controller and machine, capable of being locked open for maintenance isolation.

Elongation of hoist ropes under load and over time, which changes car leveling and must be checked and corrected during installation and maintenance.

The condition of being exactly vertical. Guide rails must be plumb within tolerance so the car travels smoothly and the safeties engage evenly.

The system of ropes, terminations, and shackles that holds the car and counterweight. Its integrity is fundamental to safety and is inspected regularly.

A lifting method using a cylinder and plunger driven by oil pressure rather than ropes, common in low-rise and freight applications, with its own valve and rupture protection requirements.

The space housing the hoisting machine, controller, and governor, which must meet code requirements for access, lighting, ventilation, and fire separation.

Machine-room-less design in which the driving machine is mounted in the hoistway, saving building space but changing maintenance access and inspection requirements.

The widely adopted North American safety code for elevators and escalators, covering design, construction, installation, operation, testing, and maintenance requirements.

Scheduled verification of safety devices such as governors, safeties, buffers, and door interlocks at code-specified intervals, with results recorded for the authority having jurisdiction.

A formal examination of the elevator by an authorized inspector to confirm code compliance, typically required before initial operation and at recurring intervals thereafter.

Authority Having Jurisdiction, the organization or official that enforces elevator codes locally and approves installations, tests, and permits.

An automatic mode in which the elevator returns to a designated landing and opens its doors on fire alarm or other emergency signal, as required by code and building design.

A test instrument measuring voltage, resistance, and continuity, used to trace faults in control circuits and confirm isolation before work begins.

A check for an unbroken electrical path, typically performed with power removed, used to verify switch contacts and wiring in the safety circuit.

The accuracy with which the car floor aligns with the landing sill at a stop, adjusted through the drive and positioning system during installation and service.

Operating an elevator from the car top during maintenance, permitted only with proper training, fall protection, and communication, following established safety procedures.