Cause of malfunction: Incorrect inverter startup parameter settings or incorrect brake time settings.

Fault Symptom: The elevator exhibits a bounce during the initial start-up phase of operation.
This phenomenon has two causes: The first is an excessively short start-up time set for the elevator's main drive inverter, resulting in overly rapid motor acceleration. Verify whether the inverter's start-up time settings are correct, as manufacturer parameters may vary. It is recommended to refer to the manufacturer's original parameters. The second cause is an incorrect setting of the elevator brake time parameter, where the brake release time is set too long. When the elevator motor begins operation, the brake remains engaged, suppressing the motor's starting force. Upon instantaneous brake release, the motor's power is suddenly released, transmitting force to the elevator and causing the start-up bounce. Adjust the brake release time to be slightly earlier. This is somewhat analogous to the sensation of driving when you hold the brake pedal down, then abruptly release it after applying full throttle.

Situation cause: Parameters were adjusted during maintenance or repair of traction elevators by technicians but not subsequently reset to their original values.