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How is output KW measured in the ATV61 drive?

FA264731

23 January 2021

Issue:
Output measured (KW) in the ATV61 

Product Line:
ATV61 / ATV71

Environment:
All

Cause:
NA

Resolution:
The power of motor is not measured by the drive. It is calculated from the measurement of motor current and the output speed (estimated in open load and measured in closed loop).
OPR = (Iq / Iqn) * (Spd / Nn) * (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
                Spd : Spd of the rotor, estimated or measured
                Nn  : Nominal speed of  motor name plate
                Phirn : Nominal flux of the motor

The accuracy of motor power is arround 10%.