Motor failure in vvfd application

[yoganand20]

we are using two motors 93KW 740Rpm 50hz class H motor for a spray pump application also the pump parameters are 2500m3/hr,suction 400mm,delivery 300mm required motor 96Kw,rpm 740 .At first we used star delta starters for the motors, it went on smooth operation taken load upto 145A. Then we decided to upgrade the starter with VVFD ,at no load the motor run smoothly .But when motor was given load after six hour/week the motor we installed was failed due to internal short . we have checked all the parameters , we dont know why both motors are failed in VVFD ,for both motors we used siemens G120 XA model . The ambient temperature of the motor is above 45 C so we have upgraded the motor insulation class from F to H. Even though we have done all the precaution , the motors was failed to carry on .

 

[Inteificio]

Hi,

I normally deal with smaller motors, but as no-one else is jumping in...

Am I right in understanding that the motors were running at full speed when they overheated and failed?

I prefer Danfoss drives, but when I was demoing the siemens units there were impressive and a close second.

The siemens drives (if I remember correctly) should have in built temperature measurement of the motors. Are you using this functionality, and how are you monitoring winding temp?

What advanced features are you using on the drives, and what protection have you programmed?

What did Siemens have to say?