Rotor adjustment/rotor position measurement

When the inverter is enabled in ELSM^® control mode, the rotor position of the permanent-field synchronous motors is unknown. For this reason, the rotor position has to be determined first or the rotor has to be adjusted by turning so that its angular position is defined.

Measuring the rotor position

The rotor position of the synchronous motor is measured with test pulses for each enable. This occurs at idle state. If a brake is used, this brake remains applied. The measurement is finished after a maximum of 50 ms. After the measurement is completed, the synchronous motor accelerates to the setpoint speed. A prerequisite for the measurement is the one-time determination of the complete motor parameters with the FCB 25 motor parameter measurement.

SEW‑EURODRIVE recommends measuring the rotor position.

Adjusting the rotor

If the complete motor data is not known, the rotor is moved to a defined position at each enable. During adjustment, a motor movement takes place depending on the number of poles of the motor. If a brake is used, this brake is released. The adjustment is completed after one second.