What mechanism is typically used to control the speed of a traction elevator?

The mechanism typically used to control the speed of a traction elevator is the variable frequency drive (VFD). A VFD allows for precise control of the motor speed by varying the frequency and voltage supplied to the motor. This flexibility in controlling speed is essential for traction elevators, as it enables smooth acceleration and deceleration, improving ride comfort and efficiency.

In a traction elevator, the motor drives a sheave, which in turn moves the elevator car via ropes. The integration of a VFD into this system allows for adjustments to be made in real-time based on the elevator's operational requirements, such as load and distance traveled, resulting in energy savings and enhanced performance. VFDs are particularly advantageous in modern elevator systems due to their ability to optimize energy use while maintaining the necessary speed and torque characteristics for safe elevator operation.