Quick Help Needed

[miki83]

Hello to all. I need some help again:)

 

My company is doing an export job, making compressors for Saudi Arabian market. The slight problem is they asked for 380V/60Hz motors to be built in, so we did, and when they were finished we connected them to a VSD and tested them with 380V/60Hz.

 

What we want to do now is finish the wiring on the compressors, since the electronics was connected to 230V/50Hz, and the motor was driven by a VSD. Normally, one part is equipped with star-delta starters, and the other is using softstarters for motor starting. What we want to do is finish up the wiring, and then try every compressor for about 1-2 minutes only to eliminate the possibility of human error in wiring the starters to the motor. I'm aware of most of the the issues, such as overflux, reduced speed etc. so i guess my question would be:

 

Is there any possibility to damage the motors this way since they would be running for just a few minutes and with completely discharged installation, meaning approx. 60% load.

 

Thanks in advance!

[jraef]

Hello to all. I need some help again:)

 

My company is doing an export job, making compressors for Saudi Arabian market. The slight problem is they asked for 380V/60Hz motors to be built in, so we did, and when they were finished we connected them to a VSD and tested them with 380V/60Hz.

 

What we want to do now is finish the wiring on the compressors, since the electronics was connected to 230V/50Hz, and the motor was driven by a VSD. Normally, one part is equipped with star-delta starters, and the other is using softstarters for motor starting. What we want to do is finish up the wiring, and then try every compressor for about 1-2 minutes only to eliminate the possibility of human error in wiring the starters to the motor. I'm aware of most of the the issues, such as overflux, reduced speed etc. so i guess my question would be:

 

Is there any possibility to damage the motors this way since they would be running for just a few minutes and with completely discharged installation, meaning approx. 60% load.

 

Thanks in advance!

 

Probably not. The issue is, over fluxing the motor will increase the current draw with relation to the load, which means the motor will run hotter under the same load than if it got the correct V/Hz. But for a few minutes I doubt you can create any permanent harm. However are you saying you are going to give the motors 380V 50Hz and they are wound for 380V 60Hz? If that's the case, would will be under-fluxing the motor. You will have less torque and slower speed, so less kW at the shaft. Still should be OK for testing though.

[miki83]

Probably not. The issue is, over fluxing the motor will increase the current draw with relation to the load, which means the motor will run hotter under the same load than if it got the correct V/Hz. But for a few minutes I doubt you can create any permanent harm. However are you saying you are going to give the motors 380V 50Hz and they are wound for 380V 60Hz? If that's the case, would will be under-fluxing the motor. You will have less torque and slower speed, so less kW at the shaft. Still should be OK for testing though.

 

Thanks jraef, I suspected that much since it's only for a few minutes but wanted to check anyway. Sorry for the mistake, I'm still pretty fresh when it comes to motors

 

Anyway thank You very much once again.

 

Regards, Miki.