Question:
For the 8400, the rated motor frequency can only be entered as an integer value. Since for synchronous motors (SM), the rated frequency is indicated with decimal positions on the nameplate, the value would have to be rounded. As a result, it may happen that the controller will not assign the correct control mode to the synchronous motor.
How can the motor data be adapted to ensure that the controller will correctly identify synchronous motors and select the corresponding control mode?
Answer:
The 8400 controller identifies synchronous motors by the rated frequency and rated speed entered. Servo control for synchronous motors will be automatically set if the entered rated frequency and an integer number of pole pairs will exactly result in the rated speed entered. In the case of deviations, the deviations will be interpreted as slip of asynchronous motors and servo control for asynchronous motors will be set.
To ensure that a synchronous motor will be correctly identified by the controller, the motor data, in particular, rated frequency and rated speed, have to be entered without rounding errors.
The nameplate data of the motor (frequency and speed) must be converted into integer numbers:
- calculate the number of pole pairs (P) of the synchronous motor from the frequency (f) and speed (n) indicated on the nameplate (P = f [Hz] * 60 / n [rpm])
- round the rated frequency to an integer value and
- calculate the corresponding rated speed (n [rpm] = f [Hz] * 60 / P)
Search terms: Motor identification, synchronous machine, sensorless-synchronous, SLPSM, SC, PSM
