Generac NP-66 Diagnostics Help

[jim3]

My generator stopping putting out voltage. Actually , there is a residual output of about 2.6 volts. Output Hz drifts between 60 and 80 Hz. Disconnected from the switch. Looked for voltage before the breakers with the breakers off. Same. Found diagnostics manuals on line and followed the process. Found DPE winding at 2.6 ohms where the manual said 1.8 plus or minus 10 percent. All other tests produced results suggesting the test passed. Help. Any suggestions? Is 2.6 ohms too high or do I need to keep looking. Any thoughts on where to look next? Any other tests I need to perform? Can anybody point me to part numbers? I have a couple calls into Generac and so far, no response. Thanks!

[JRMEDPHYS]

Hi Jim:

I just went through almost the exact same problem for the last couple of months. I suspect it could be one of two problems, or both as in my case...

1) Loss of field boost function
2) Stator DPE windings are fried

When I first got the problem you describe, adding a field boost uplift kit from Generac fixed the problem. The part number is 0H07850SRV and I have attached a .pdf of how to connect it. Cost about $90. Gennie worked good for a while.

Later, I lost the stator DPE windings and had to put in a new stator. Got mine from the factory through Gen-Tech (Arizona) for about $380 (P/N 087845H). It's not a repair for the faint of heart but it can be done. Took me and my brother-in-law a weekend to make it right.

After putting in the new stator, I tried to run the gennie WITHOUT the field boost uplift kit and was still only getting 2VAC. After re-installing the field boost uplift kit, it has worked absolutely flawlessly ever since.

Good luck!

Jeff