Burnt Alternator Winding on 150kVA Alternator With 25kW Engine in Paralleling Setup

Hi,
We have this diesel generator that is refurbished and is part of a paralleling generator set.. The Alternator, engine, avr and controller are all refitted and are are different brands. The engine is rated 25kW...The alternator is rated 150kVA.....However, the alternator burns.....What could be the problem?

What do you mean by “paralleling” Could what you are paralleling
with be overloading the windings either by current or voltage?  Is it the stator or rotor that is burning out?

 My experience on standard gensets of lesser power is that it’s
overcurrent that degrades the stator insulation by overheating it. Also have
you got the wrong type of load? E.g. one with lots of kVA but little kW may not
be kind to the windings. Is the winding cooling good?

 If the AVR and controller is of a different brand are they properly matched? To me an AVR is a controller so what is the difference to you? Is the engine going at the right speed to generate the right Hz?

Bad diodes are a common cause of alternator failure. Normal driving and charging loads won't burn out the diodes, but infrequent driving and short trip nighttime driving with lights and other accessories on can increase charging loads and significantly shorten their life.