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Discussion Starter #1
Its a Chinese made 24kw 4 cyl genset. Brushless diesel.

Engine starts clean, achieves 1800 rpm, voltage on meters are good 115/230.

Runs fine until I engage the 100amp breaker. Voltage readings disappear and load is not powered.

The control fuse on the 8amp AVR board pops.

Changed AVR board, still same fuse blows on new board.

Breaker inside in building is opened and there is no load connected at all, fuse blows.

Breaker is 3-pole. Breaker is also connecting and lifting the neutral from the windings.

I put an extra large fuse in the control AVR board and tested the following way ...

I flip the 3-pole breaker on and off real quickly and there is arc'ing in the windings when I do this.

It appears there is a short somewhere in the windings to the chassis/frame. With the 3-pole breaker OPEN, I can apply a 240 volt heater load to the windings side and it operates beautifully. Electric Heater warms and engine purrs.

If only I didn't need a neutral I'd be golden.

Any thoughts ?

Since it is brushless I was hoping to find a diagram of the windings. I can deal with half power even if I had to disconnect some windings to get any output.
 

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Discussion Starter #5
leaving

Well this user is now leaving to go to another forum. I had photo of burnt winding and arcing to share. Guess not.

And thanks for the hint (NOT) that wasted an hour of my time trying to figure out what I was doing wrong. Geesh.
 

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Discussion Starter #6
only 1.5 ohm

Just measured the field winding resistance. Should be about 30 ohms and it reads 1.5 ohms. When connected to AVR it blows 15 amp control fuse thereon.
 

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Is the short winding to winding or to the case?
I ask because you were able to apply a load to them earlier with no issues.
If it's to the case there may be debris causing that, not a blown winding. The core of the alternator can be pulled and cleaned. Re-meter the windings with it out.
 
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