Unsymmetrical incoming current on frequency inverter

[Anonymous user]

Hello,

During commissioning of a 315kW ATV660 drive, I've measured the incomming current.

The 3 phase currents have not the same value L1= 580A, L2=565A, L3= 575A.

Is this problematical ? How can advice ?

Thank you for your kind advice!

[ReinhardK · Accepted solution]

This is an unbalance of 15A between L1 and 2 (2,5%). Such a behavior is indicating,
that the 3 phase incoming voltage is slightly different or distorted. You can check
with an oscilloscope the voltage waveform, verisimilar the voltage is distorted
slightly on it´s top. Could be caused by some nonlinear loads which emits a 3^rd rank harmonic.
But anyway, don’t worry this is not a problem for the drive itself. 

[Anonymous user]

Thank you @ReinhardK , this was very useful.