Sensorless Vector Control (SLVC) operation relies on continuous recalculation of the rotor position, and if, for any reason, the motor position information is lost (“Loss of Orientation”) the response of the drive is unpredictable. Loss of orientation can be caused be an incorrectly commissioned motor, loss of motor temperature information following power failure, or similar disturbances.

Sensorless Vector Control requires careful commissioning and setting up. This should only be carried out by commissioning engineers who have experience of operating MM440 / G120 drives in SLVC.


Important Note:

SLVC should not be used:
1. where the motor inverter power ratio is less or more than 1:4
2. where the maximum frequency is greater than 200Hz
3. on multi – motor applications
4. If a contactor is placed between the inverter and the motor; respectively the contactor must never be opened whilst the inverter is running.
5. for hoisting applications

It seems that motor identification is very important for SLVC, and that it cannot be calculated for more than one motor at a time.
Please have a look at the complete FAQ for more details.
Hope this helps,
Daniel Chartier