How elevators are made

A traction elevator is balanced by a counterweight, so the motor lifts only the difference between the car and its load.

stations: 8
things upstream: 78
raw sources: 26
steps from the ground: 9

The short version

An elevator is a car hung on steel ropes that loop over a drive sheave and down to a counterweight. Factories roll guide rails, weave the ropes, build the cab, and assemble the motor, brake and controller. The parts are then installed in a shaft, adjusted and tested, including the safety brakes.

Roll the guide rails

Steel rails are rolled and machined straight. They run the height of the shaft and keep the car and counterweight from swaying.

Goes in
Steel
Twist the hoist ropes

Strands of steel wire are twisted into rope that rolls over a grooved pulley, called a sheave. The ropes carry the weight of the car.

Goes in
Wire rope
Build the cab

Panels of sheet steel, stainless steel or glass are fitted on a steel frame, with floor, ceiling, handrail and lights.

Goes in
Sheet steel Stainless steel
Assemble the drive machine

An electric motor, brake and sheave are mounted together. Gearless machines connect the sheave straight to the motor, and the best of them reach speeds of up to 20 m/s.

Goes in
Electric motor Ball bearing
Load the counterweight

A steel frame is filled with heavy blocks, sized to balance the car plus about half a full load.

Goes in
Steel
Wire the controller and doors

A controller reads the call buttons and floor sensors and commands the motor. Door operators and safety switches are connected.

Goes in
Printed circuit board Copper wire
Install it in the shaft

Technicians fix the rails in the building, hang the car and counterweight on their ropes, and set the machine in place.
Test the safeties

Inspectors check that the brake holds on loss of power and that the emergency gear grips the rails. A spring-applied brake engages on a power failure and stops the car from falling.

End of the lineElevator Next it goes into skyscraper.

Worth repeating

Frank Sprague improved the electric elevator with floor control, automatic operation and acceleration control.
Gearless traction machines were introduced in the 1930s, and AC permanent-magnet machines with inverters appeared in 1995.
Many elevators in a bank are run so their cars move in opposite directions, each acting as the other's counterweight.