Dear experts

As you see ,we have a very unbalance phase current at drive output,when the output voltage is very fine.

So,does anyone has any idea about what is going on here.

Best regards 

Thanks

For a good understanding we need more detail, with regard to this installation, motor, drive, application, cable length etc.

Has the motor been confirmed as serviceable?

Thanks for your attention,

Our system configuration is ؛

S120,vetor v/f mode ,power module 1200 kw,

Single motor parralel winding delta connection ,single drive,

no motor side filter,

Same cable size (abut 4 meter)

Motor suitable for sinamic drives.

+Motor data sheet :

The motor speed appears slow during the trace, does the trace appear similar for full speed?

The parallel motor connections, they all have correct polarity??

Does the motor appear to function correctly when driving the load?

Thanks,

Motor does not go over 100 rpm ,due to overcurrent.

We test each winding separately same result ,exact same shape for U,V,W.

Could it be because of to much harmonic current? 

If so ,Which parameter change will help to reduce the harmonic?

Best regards

The speed is low, so some questions come to mind:

The motor will have external cooling I guess?

The drive is firing at very low frequency, and for this to be continuous, may cause a problem for the IGBT. The current will be applied for an extended time during each 'on' period, this may exceed the duty for the semiconductor block.

The full load current for the drive is seen at this low speed, what is the machine that is being driven?

Thanks for your help ,

Yes there is a water cooling and motor is in no load test ,this is a ship propeller.

Today with the help of you and other guys we finally did it.

The  cause of the problem was the harmonic current and we reduce it by changing the modulator to edge modulation and increase the pulse frequency to 5 khz and some other thing that I could not find which one was more efective fo now we are working on adding a THD filter also.

Thanks to all

Best regards