rapidroy5858
Once again getting the start,run 15 seconds then shut down on my 04390-3.
last time it was the rotor stator , had them replaced, has been fine for last 3ish years but now getting same symptoms.
using fluke meter and following test procedures in repair manual the rotor stator seem to test good,but
> not getting voltage at breakers .
> not getting voltage at connector j1 pin 8 wire 66
> wire tests good for continuity back to connector c2
> confused why rotor stator testing good but no voltage at the mentioned wires and at breaker when unit runs for 15 seconds, any ideas ?
thanks in advance
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BrentB
Test field boost during cranking.
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rapidroy5858
Thanks for the reply, I will try the field boost test but cant find the procedure any info on where I can find it?
would a failed test there indicate a problem not related to rotor stator?
Thanks
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Peddler
You need to do a fixed field boost test by jumping 12VDC to the #4 wire going to the brushes and see what you have at the generator side of the breaker. If it produces some voltage record that amount and report back.
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rapidroy5858
We did field boost test read 11 volts on wire 4. With #2 connector unplugged.
Did field boost test with connector c2 plugged in and read no voltage on wire 4.
we did fixed field test with 12 volts to #4 wire at reg, unit would run had red light on voltage reg and 216 volts on gen. Side of breaker.

unit would run and produce power until 12 volt jumper was removed from #4 wire, when jumper was pulled off the unit ran about 8 seconds and would die.
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Peddler
Ok you now need to read the voltage on the bottom two wires 162 and 6 I think which are the DPE winding. If you have about 100+ voltas on those when the #4 wire has 12VDC jumped to it you will know it is the voltage regulator which has failed,
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rapidroy5858
We just found the excitation circuit breaker is open (bad) so we jumped circuit breaker wires together and applied 12 volts to # 4 wire. We then had 140v across wires 6 and 162.

We applied 12 volts to 4 wire while wire 4 was still attached to reg. And smoked the regulator. Not sure I caused that by leaving 4 plugged into the regulator.

so it appears I need a circuit breaker and a regulator. Not sure if I have a problem with the field boost circuit sense I had no voltage on wire 4 while cranking engine with connector c2 plugged in.
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Peddler
Leaving 12vdc on the regulator with the #4 connected should not have done anything to the regulator. Did you try to see if it made power with just the DPE breaker jumped? I never jump the DPE breaker with anything other than a 5 amp blade fuse. If the VR has a short you could burn out the DPE winding so be careful.
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BrentB
The 12 volts on wire 4 comes from the PCB during the crank cycle, which turns on the voltage regulator. If the PCB isn't putting out the 12 volts during the crank, that's the first thing to correct.
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rapidroy5858
We do not have 12 volts to wire 4 when cranking.
when we apply 12 volts to wire 4 we get red light on vr and unit runs with voltage to gen side of breaker.as long as we leave 4 wire jumped,unit shuts down as soon as we remove jumper wire.
we have 140 volts from dpe winding at reg when unit is running with jumper on 4.these results are same whether we have breaker jumped or not.
is there a test to check function of PCB and reg that will tell us definitely if they are good or bad.
It seems that once unit is running with 12 volts to wire 4 and input voltage from dpe unit should stay running when we remove the 12 volt jumper?
thanks for your input.
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Peddler
Clearly you have a bad VR, the question is what caused the DPE breaker to fail. Dirty slip rings can do this as it can take extreme voltage to push through the high resistance. On the field flash I would wait to address that after you have replaced the VR. With a digital meter it is sometimes hard to capture the field boost on the #4 wire. See what happens after you install the VR, as you point out if it is still not catching the flash try jumping it with the battery voltage and then removing it it should stay running. There are a couple ways of correcting the lack of field flash both of which have pros and cons.
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rapidroy5858
It's been a while since we have been able to work on unit but did so today.
Installed new vr.
installed new dpe breaker started unit, it ran 15 seconds shut down,reg did show red light lit did this repair few weeks ago but could not continue to work on it due to being busy.
Today.. Tried starting again..red light did not light up, it ran 15 secs. Shut down.
found wire at big(long) plug on control board had a wire that had come loose. Repaired it so it would stay in connector when plugged into board,restarted ran 15 secs shut down , no light at reg this time, restart jump #4wire at reg runs produces power.
Checked DPE BREAKER FOUND THE NEW ONE HAD FAILED.
Installed 5 amp fuse on wires that attach to dpe breaker unit starts,runs ,produces power normally.
Unit works normally now with 5 amp fuse installed ,can I leave fuse in place or do I need to purchase another breaker?.
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rapidroy5858
Any suggestions?
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Peddler
I would guess you have a bad stator or rotor leaking to ground . At no load the DPE winding should not require more than 1 amp to provide enough current to the VR. You will have to carefully test the various circuits and stator leads to see what exactly is going on. This will require a very good ohm meter, a megger. I would first ohm the #4 wire and the #0 wire at the VR to make sure you don't have excessive ohms across the brushes to the slip rings.
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Birken Vogt
I just had one of these regulators fail in a manner similar to this. The DPE inputs to the regulator were pretty close to shorted inside the regulator. The DPE breaker did not open in the short time I gave it. I gave it a 12V field boost and the DPE wires started getting hot and smelling immediately. Of course the regulator would not stay on on its own when field boost was removed. New regulator and all was well. As far as I know.

So don't discount that the old, bad regulator could have failed DPE shorted and damaged the DPE breaker and whatnot.

And yes, I have also used a fuse temp. in place of a DPE breaker. Be sure the fuse is rated at least 120v if not 240.
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rapidroy5858
Installed the dpe breaker, unit now starts,runs,produces power.
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