Determining characteristic electric and mechanical parameters of asynchronous motor

摘要

The method provides determination of characteristic electric and mechanical parameters of a three-phase current asynchronous motor using a run out search without using measurement means for rotation rate detection. At least the parameters rotation rate, rotation rate drop after a given measurement time, braking moment and braking power are determined. The three phase currents of the motor are detected during the free run operation. The run down search is initiated by switching the current in the natural zero crossing. During the measuring time, the clamp voltage amplitude and frequency are detected, digitised and stored. At least the rotation rate, the rotation rate decrease, the running rate, the braking moment and the braking power are calculated from the clamp voltage. Further parameters e.g. bearing and ventilator loss, as well as iron and friction loss, can be determined using motor specific models.