50/60 Frequency converter VIBRATION

[Mohamed haggag]

Hi Guys,

I just commissioned and tested a 275 KVA Piller frequency converter which was in service before, while it was off-loaded there was No vibration generated, but when we loaded it we start to see some vibration from the equipment, there were 4 Rubber bases that absorbed the vibration and the Main four bases weren't fixed to the floor through bolts, would you help if any of you faced the same before or any recommended actions please?

 

[EdStainless]

So this is a solid-state unit?
Go inside and check the mounting of everything.
Some of ours (various sizes and makes) did and others didn't.
We never had a good answer.

 

[Mohamed haggag]

Motor and generator coupled together , panel is separate and has microprocessor
the equipment works fine and we have 60 HZ output , what makes me not happy is the level of vibration

 

[EdStainless]

We only had one MG set still running, so much can go wrong.
It was a 60-400HZ unit.
Check bearings, shaft play, and shaft alignment, make sure that the coupling is installed correctly.

 

[waross]

Unbalanced rotating field. Shorted windings or unequal turns. Unequal air gaps.
As the load is increased, the field current is increased. Anything that causes a different magnetic flux in one or more poles may become more pronounced as the field strength is increased in response to loading.
This may cause the vibration to increase from acceptable to unacceptable.

 

[edison123]

Is it monobloc or separately coupled? Is it vertical or horizontal? Post a few pictures and the nameplate.

Most likely, the generator rotor has interturn shorts if the vibration starts only when the generator is excited.