Traction Elevators utilize a motor and gearbox located at the top of the hoistway to provide lifting power. The car is lifted by chains that run over pulleys at the top of the hoistway, and then attach to counterweights. Counterweights are used to offset the weight of the car, making the raising and lowering require less power. This means that the motor can be smaller and quieter. The motor typically utilizes a variable frequency drive which allows the motor to ramp up and down smoothly, similar to hydraulic operation. The elevator controller (approx. 25’W x 23’H x 8”D) can be mounted in the hoistway, eliminating the need for a machine room.
The benefits include no-machine room design, energy efficient, lower cost, smooth start/stop. The no-machine room option saves space in your floor layout and cost in materials. The smaller motor utilizes less energy than other types of elevators. The traction elevator is ideal for 3 or more levels as the incremental cost for increased vertical travel is much less than hydraulic elevators.
The negative points include some noise from above, and difficult manual lowering. Since the motor is located in the hoistway, you can hear the humming of the motor as it runs. It is not loud, but you are aware of it. If the elevator stops between floors for any reason, manual lowering requires the use of a hand crank.