Electrical three-phase asynchronous motor i.e. three-phase asynchronous motor having squirrel cage, operating device, has switching or program part and control component increases ignition to decrease voltage-time surface of motor voltages

摘要

The device (1) has a switching block (15) determining a measure for an actual phase angle between current and voltage from the phase shift between main or motor voltages and main or motor currents. A program part (16) and a memory (17) determine or estimate a relative load of a three-phase asynchronous motor (2). A switching or program part (18) and a control component (19) decreases and increases the ignition angle if the actual phase angle is less and greater than a load-dependent optimized phase angle to increase and decrease a voltage-time surface of the motor voltages, respectively. An independent claim is also included for a method for operating a three-phase asynchronous motor in a delta connection.