epa007
Hi,
I have a Generac Model 0058710,Serial 5954142 running on LP. Generator start and shut down After about 7-8 seconds and display UNDER VOLTAGE. Measured from wire 4 to 0,OL.Get to the brushes, one was broken, so replace the brush ASSY 0663860SRV.Place everything back start the generator and the same problem in there.Field boost diode is good and there is battery voltage while cranking.

DPE winding 2-6 1.5 Ohms, Not shorted. So I cut wire 4 crank the engine and manually place battery volt to the + brush and, BINGO there is the output 205-210 VAC , keep gen running a few minutes, DPE winding 148 VAC,no output from wire 4, controller side .Engine shut down because UNDER VOLTAGE when I remove the jumper from brush side wire 4 to battery.Thanks
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Peddler
Well I guess the first thing to do is to make sure the DPE winding voltage is making it all the way to the controller. Then verify the #4 wire back to the controller to make sure it is connected to the controller output pin for the #4 wire. Lastly if you are getting field boost which comes off the starter circuit you should see some voltage during cranking on both the DPE winding and the main winding. If all of those circuits are OK then you most likely have a bad controller. In the field it would be one of the first things I would try but I have controllers in stock so it is no loss if it turns into a dead end. Good Luck.
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MacL
Let me second the controller. It is a Nexus 0H6680A, which will have to be converted to a 0H6680DSRV. Pretty expensive, unless it's already been converted. If already converted you would just need a 0H6680D board.

I think there could have been a way to flash the field without actually cutting a wire. I would have released the terminal from the Amp Seal connector before I would cut a wire, but would have probably accessed the wire under the shrink tubing on the field boost diode.

But I keep a couple of 0H6680SRV's on the truck and would have plugged it in, but not mounted anything, it would have fixed the problem, and I would have never manually flashed it.
State your problem, not your diagnosis.
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epa007
Good morning,
Im confused.Only the brush assy was mounted,one brush was broken.Controller is the one factory installed.Conversion needed?
By the way,can I just make a test with a 22kw controller and wiring resistor?
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Peddler
Some of the early controllers had different style plugs on them then the current generation and a conversion is needed. As to why you had a broken brush and now the controller I can't answer. Sometimes the repair cascades and you have to fix multiple problems. Is it possible that the brush broke when you were removing it?
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epa007
If you know,Can you describe the conversion from OH6680A to a 0H6680DSRV.Whish parts/materials needed.
Is 0H6680DSRV supersede OH6680A?
Thanks
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epa007
I already find out that H6680DSRV is a Kit, with OH6680D and a harness kit. Thank you
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epa007
Hi everybody,

Back to you. [LEFT][COLOR=#000000][FONT=Helvetica][SIZE=13px]I'm willing to purchase a new controller kit, but[/SIZE][/FONT][/COLOR][/LEFT] I want to share with you the following information before purchasing a new controller Kit,
,
DPE Wires 2-6 Rotor Wires 4-0 Power Winding Wires 11-44
Continuity Ohms .8 16.9 .8
Field Boost, VDC
*CRANKING ** 17-18 Vac * 10.6 VDC * 25 Vac *10.8 Vdc Wire 4 and 11.7 Wire 56


Running No load with a jumper from + batt to Wire 4

142-145 Vac
209-210 Vac Generator continue running without showing any alarm.

From the expertise side ,are those values marked with * are good to continue generating by itself with a new controller?
Thank you
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MacL
epa007;n58504 wrote:



Running No load with a jumper from + batt to Wire 4

142-145 Vac
209-210 Vac Generator continue running without showing any alarm.

From the expertise side ,are those values marked with * are good to continue generating by itself with a new controller?
Thank you


All those values seem normal. I don't know about the 17 to 18 vac (other than wire 18), but it's probably not important. I'd also expect what you get when energizing wire 4 with a jumper.

The whole problem is that a portion of that circuit board is an Automatic Voltage Regulator, which is the source of the electricity on wire 4 to the the rotor windings, has gone bad. As of now the AVR has no output to wire 4 and the board probably does flash--flash drops out at about 2200 rpm--but the failed AVR does not turn on during flash (field boost) and then take over supplying the field with a dc voltage to maintain the proper output.

So, yes, if you provide a continuous voltage of 12 vdc to the field you will get some low voltage production, as typical field voltage is about 30 vdc. But the AC voltage produced via the 12 volt flash is enough to turn on the regulator, which then takes over and raises the voltage to its set point.


State your problem, not your diagnosis.
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Peddler
Just to be certain we are on the same page are you saying that when you pull the 12VDC from the 4 wire it will continue to produce the rated AC voltage? If it falls back off it is defiantly the controller if you also have voltage on the DPE circuit. If it continues to produce rated voltage after removing the 12 VDC from #4 then you may have a problem in the flash circuit.
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epa007
Hi to all,
controller replacement kit arrived yesterday.Will work on this.Thank you
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epa007
Problem solved replacing the controller,replacement kit installed and generator is generating.Thank you for your advise.
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