Synchronous motor applied to frequency inverter

Question:
Can a synchronous motor (e. g. SDSGS synchronous servomotor) be applied to a frequency inverter?

Answer:
Synchronous motors can also be applied to frequency inverters (e. g. 8200, 8200 vector, 9300 vector, ...) in V/f characteristic control (open loop without encoder). Here a speed precision without feedback system can be realised by the synchronous rotating of the rotor to the rotating field.
Condition:

• No high dynamic
• Only small load impulses

Actual drive controllers (e. g. 8400) also support an open loop control of synchronous motors without mounted encoder (Operation mode: 'SLPSM').

Due to the following reasons the application of a reluctance machine instead of a synchronous machine is to be checked in V/f characteristic control:

• If the pull-out torque is exceeded, the reluctance motor does not lose the complete load, but only 'puts out'.
• More favourable price compared to the synchronous machine
• In case of synchronous machines the motor voltage is often to be lowered due to current overshoot, e. g. via a CURVE function, thus, commissioning requires more efforts  

Further information about the functional principle of synchronous motors see also under Wikipedia.org: Synchronous motor