Frequently asked questions

FA272937

28 September 2021

Issue:
Otr motor torque parameter calculated on the ATV61 and ATV71 drives.

Product Line:
Altivar ATV61 and ATV71

Environment:
All

Cause:
Needs to know how the motor torque Otr parameter is calculated

Resolution: 
The torque of motor (OTR) is not measured by the drive. It is calculated from the measurement of motor current.
OTR = (Iq / Iqn) * (PhirdRef / Phirn) in %
With:     Iq : Current torque provide by the command to drive motor
             PhirdRef : Flux provide by the command to drive motor
             Iqn : Nominal Current torque compute with the motor name plate
             Phirn : Nominal flux of the motor
The maximum accuracy of motor torque is 5% (in closed loop). It can be up to 15% in open loop.
Concerning the range, OTR is expressed in % of nominal motor torque.
100% = Nominal motor torque.
OTR value is signed with minimum value -300% and maximum value 300%