alfredoma
Can someone please help me figure out this problem.  My unit was turned on manually upon power outage, after about 5 min it shut down. since then the gen starts for about 7 to 10 sec. then shuts off. I do not get any voltage output at the breaker. I replace the brushes no help. when I remove the #4 wire at the voltage reg. and supply 12 vdc to the wire, the gen stays on but still no voltage output. I do get about 62 v at wire 162 & 6 (just have to make sure of that again) the light on the reg is barley lit . The main breaker is good and I do not see voltage across its terminals. Any advice on what to look for The Gen is a 13 kw mod 04390 LP fuel. 
BTW the LP fuel pressure is good and it has worked for a long time without any issues. I do not have voltage on wire 4 at reg. I think upon cranking i get some voltage at #4 for a moment.

thanks
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78buckshot
When you replaced the brushes did you happen to check the resistance across the slip rings? You can still check it through the #4 and #0 wires after removing them from the regulator. The issue could be a bad rotor, bad stator, bad voltage regulator, open DPE breaker, bad DPE windings, or any of the wiring related to these. I think you measured #2 and #6 and found 30 volts, that is the DPE circuit - sounds like it's ok, my first suspicion is a bad VR.
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Peddler
With the 12 VDC on the 4 wire you should have 90-160 volts line to line at the generator side of the breaker and I would expect more than 30 volts on the DPE circuit maybe 90 volts.  If you have zero or nearly zero at the breaker and 30 on the 2 & 6 wire I would guess that your rotor may be ok but the stator is bad.  In any case you will have to replace both as that is the only way you can buy them at this point.  Couple thoughts here.  1) if your results are certain I think you should consider buying a new unit instead of fixing this one.  It is pretty old and doesn't have the features of the newer units.  Unless you can do all the work yourself it will be over half the cost of a new one maybe more. with no warranty.  You may be able to get in on a 10 year warranty deal now going on.  2) If fixing the cheapest way I would try to find a used but working 4390 unit (there are a lot out there available) and either swap the unit out or move the needed parts from one to another.  You should be able to find a working unit for $500 or less which is half the price of the parts.  Good Luck, Peddler
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alfredoma
Thanks all for your advice. I did not check the slip ring resistance will do so today. I was mistaken on the voltage read its 62 volts at wire 162. with 12vdc at #4 i still do not have any voltage at gen side of line voltage at breaker. I am thinking the VR is shot. but do not want a parts cannon going into this old unit. Dont mind a VR if that could be the resolve to the issue but not a new rotor. I will do some more test today as per the manual and report latter. Will be more detailed on the readings. Thanks you all.
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Peddler
If you have voltage on the 162 wire and none on the generator side of the breaker then it is not a VR issue it is Stator / Rotor.
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alfredoma
hello again, thanks in advance for your advice. Here is the latest and greatest. I did clean the slip rings they were pretty dirty. shinned them up. with that said no real help to the problem. what I did do is the following;  tested field boost voltage by disconnecting wire #4 at the VR. put a +meter lead at the wire. - to ground. upon non crank I get 0 volts. when cranking I get 11.2. Test #2. disconnected wire #2 from Excitation breaker put test lead at wire. Disconnected wire 6 at VR connected test lead there.  results = 77vac. put that back, then disconnected wiere 11 from VR connected test lead to it. disconnected wire 22 from VR connected it to the other test lead. results = 8vac. I have a clamp on amp meter, can't do an amp test until i get a regular type amp meter to put in line for that reading. Main CB is good by the way. Test 3. I remoed wiere 0 from VR connected lead to wire 0 the other to clean ground result good continuity. Disconnected wire 162 at VR the other end to CB connected lead to it result. good continuity here as well. So My issue is do I get a new VR is this my problem or is it deeper elsewhere. with 12dc applied to wire #4 I do not get any line voltage. and unless I apply the 12dc to #4 the gen conks out after about 10 sec. Hope I have given good info for some advice. Thanks again for your input. BTW what dose DEP stand for.?
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78buckshot
If in fact your are keeping the zero wire grounded and applied 12vdc to the #4 wire and have no ac output then you have a bad rotor and/or stator. It sounds like you have a diagnostic manual, follow the flow chart to test rotor and stator. DPE - displaced phase excitation, that is a separate winding within the stator that feeds ac voltage to the regulator, wires 2 and 6.
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alfredoma
Thanks 8 buckshot. I will do rotor/stator test as per manual will report back upon my findings. many thanks.
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Steve H
is it common for the rotor and stater to go bad in these?  In the electric motor world, they rarely die unless the motor is grossly overheated.  I can't see that on these.  Lots of air flow
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Peddler
My guess is the rotor is OK but they are normally sold as a set though some can be purchased individually.
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