jebsracn
Centurion 20Kw
Model #:0058961 Serial #: 6864292
Nexus 0H6680D
NG feed about 15'of 1" from meter

Looking for professional opinion and/or make sure I didn't miss something.

Got an under-voltage alarm on our generator last week. Was in auto mode. My son told me that it tried to exercise, but it would just start and die. I went out found the alarm tried to start it in manual same thing start and die. I checked ALL the fuses (pulled them, checked with a meter, good), checked battery voltage (13.xx w/ cables on, 12.7xish unhooked). Unbolted the controller checked the connectors and wires for burnt or melting all good there. Read that the brushes could be the problem, started to check the brush circuit. The diode seamed ok (continuity one way, switch leads nothing) I checked for continuity between the blue#4 wire and black#0 at the controller connector had OL (open). I was going to check for an open wire between the controller and brushes, but can't get to brushes without removing the side, blower, ect... Got all that off thought while I'm here I'll check for continuity at the brush holder, it was OL. Removed the brush holder, brushes looked good.I tried to check the slip rings,but had trouble getting meter leads up in there, so I removed the end housing. The slip rings were a little black so I cleaned them with emery cloth. I checked ring to ring it was OL, and each ring to the shaft was OL. At this point I'm thinking that I have a bad rotor. Shouldn't there be some sort of resistance from ring to ring? Before I spend $500-$600 on a rotor I wanted to get a second opinion or if there was something else to check.
Thank You for your time
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Peddler
Ring to ring there should be some resistance about 18 ohms, that is just a guess i will have to look up the specs to be exact but if you are reading infinity you have a bad rotor I'm afraid.
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78buckshot
I think 9-18 ohms are the spec, are you sure your meter and leads are good and check it's accuracy.
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jebsracn
I checked my meter today tip on tip it is reading 00.0 - 00.1 ohm.

I checked it a little more today. Again ring to ring "OL". I turned the rotor so that the wires going in the back of the slip ring was one on the left,and one on the right. Checking at the wires it measured about 10.6 ohms. From the right side to the back ring (second from the bearing) measured about .2 ohm and OL to the front ring (closest to bearing). The wire on the left measured OL to both rings. I'm assuming now that the open is between my left wire and the front ring. So the million dollar question is can you replace just the ring or re-solder the wire?
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