mep002 FVR 4006 Regulator Source?

[Speddmon]

David,
I'm sorry that cleaning up the magnets and fixing the bare wire didn't solve your problem. One thing the tests in the TM do not check for is insulation breakdown. That is obviously what you have going on with your stator. The Ohm readings show up good, and the readings to ground show up good, but as soon as you start putting some amperage through it, the insulation must be breaking down and basically shorting out part of the coils. The only way to test for that is with a Meggar, most people in the general public don't have one of those. Luckily for me, I'm not most people...LOL

Good luck with your new stator and check back in with us and let us know how it works out.

 

[PeterD]

Actually you check for shorted turns in a coil with a 'growler' not a megger. But that device is also not commonly found in must 'home' shops--usually only someone who is doing motor/generator work has one. It consists of a V shaped iron core with an electromagnet wound on it. The coil is energized, and the winding being tested is placed in the V (such as a motor's rotor) and turned, You can actually hear the difference between a shorted coil and one that is not shorted. (It makes a more pronounced growling sound).

The photos shows windings with a large sized wire (perhaps 14 AWG) and if so they are very easy to rewind. You can get the wire (look for magnet wire) on eBay.

 

[David Sims]

stator installed

I installed the new-to-me stator today. Started the generator, let her run for 30 seconds and while at idle I pulled the negative battery cable closest to the fuel tank. With the cable off, the unit continued to run. Victory! I thought.
After 5 seconds of glory, as I was reconnecting the neg cable back onto the battery I got a spark as the cable touched the neg battery post and the unit instantly died.

I went to restart the generator to take meter readings at the Voltage Regulator (which I suppose I should have done to start with) and found the DC Control Breaker tripped. I reset the breaker and twisted the Master Switch to the right twards the Prime position to start only to have the DC Control Breaker to trip again. Reset the Breaker and tried again, same thing. The DC Control Breaker trips the instant the Master Switch is twisted.

I have a fresh pair of batteries and the DC reading is 25.1.

I opened the Control Cubicle and did not see any obvious problem like a smoked part.

I apprecate any directions on where to start..

 

[PeterD]

Considering it is never a good idea to disconnect a battery (or connect one) on a running alternator, I'm not terribly surprised something died. Possibly the regulator, in automotive style systems, that is usually what gets blown, by the surge of disconnect/reconnects.

 

[David Sims]

regulator

PeterD,

Is the regulator you mentioned the voltage regulator? If so I disconnected the Voltage Regulator and the breaker still trips.

Thanks,

David

 

[PeterD]

Yes, that is the regulator. However, the surge when the battery was disconnected may well have damaged something else. I guess standard trouble shooting is the way to go now, see if you can find where the current is going. Pay attention to any filter/bypass capacitors as they can short when subjected to excessive voltage. One trick that is done is to put a 24 volt light bulb in series with circuit breaker to temporarily limit current. Then watching the bulb's brightness, start disconnecting things and see when the light goes dim or out.

 

[Speddmon]

There are only a few DC operated things on the set. First off, since you said it happens when the switch is turned to prime run, I would start be disconnecting the fuel pumps and see if the circuit breaker stays in. If it does, then connect them one at a time until you find the culprit. If it happens to be one of the pumps, it's probably the inline capacitor like Peter mentioned. That can be cut off and the fuel pump can be run directly without it and you should see no ill effects.

After that, there is really only the charging system and the fuel shut-off solenoid that uses the DC. If it's none of those major components, then we'll need to look inside the control cubicle.

Also, if you didn't catch it in the previous dozens of threads on the subject...DO NOT LET THE GENERATOR IDLE!!!!!!!!!! If you let the engine idle, you are gonna have a lot more to worry about than the DC stuff not working.

 

[David Sims]

E3

There are only a few DC operated things on the set. First off, since you said it happens when the switch is turned to prime run, I would start be disconnecting the fuel pumps and see if the circuit breaker stays in. If it does, then connect them one at a time until you find the culprit. If it happens to be one of the pumps, it's probably the inline capacitor like Peter mentioned. That can be cut off and the fuel pump can be run directly without it and you should see no ill effects.

Speddmon,

That was it. I unpluged Fuel Pump E3 (it's on the inside of the fuel pump bracket) and the problem went away. I don't have the readings with me but the VR was putting out a higher DC voltage with the machine running at 1800rpm than the battery voltage was when the unit was off.

I connected the shop and ran her about 3 hours at a little over 50 % rated current @60Hz. It was good to see the battery indicator inside the green zone for a change.

Would you replace the E3 capacitor?

Thanks,

David


After that, there is really only the charging system and the fuel shut-off solenoid that uses the DC. If it's none of those major components, then we'll need to look inside the control cubicle.

Also, if you didn't catch it in the previous dozens of threads on the subject...DO NOT LET THE GENERATOR IDLE!!!!!!!!!! If you let the engine idle, you are gonna have a lot more to worry about than the DC stuff not working.

Thanks for the heads up on the IDLE issue - I'll do some reading on this subject.

 

[Speddmon]

No, I wouldn't bother replacing that capacitor. The pump should run just fine without it. It's not like there are any fancy electronics in the pump to protect, it's just a motor after all.

 

[Keith_J]

Bringing new life to this thread...the capacitors on the fuel pumps are critical because the fuel pumps are solenoid actuation and every time they click off, a reverse pulse of electricity flows. Reverse current is hard on the internal switching and can damage the voltage regulator on the battery circuit.

The fuel pumps are minor in this compared to the governor solenoid. I have a fix for this problem which can damage the low oil pressure switch. A flyback diode on the governor solenoid will snub the back electromotive force, saving the oil pressure switch and thermal cutout.

 

[crazymechanic]

wow just read this whole thread ... same problem I wont be disconecting the batteries while running

how do you make the flyback ?A flyback diode on the governor solenoid will snub the back electromotive force, saving the oil pressure switch and thermal cutout.

 

[Keith_J]

Flyback diodes are equivalent to freewheeling diodes. Just a power diode over the terminals of the solenoid. Cathode to P66H16. Anode to P55T16. Get it wrong and it will pop the DC breaker. Or fry the diode. During normal operation of the solenoid, the diode doesn't conduct, reverse bias. When the solenoid is deenergized, the collapsing field generates a reverse voltage. Now the diode is forward biased and conducts, providing a path for the current generated by the collapsing field.

Some solenoids may have this built in. Others may have lost the internal diode from wear/abuse/improper solenoid installation.

 

[Bill W]

Got any pic's or diagrams or even crayon drawings of this setup for us electrically impaired folks to look at

 

[m38inmaine]

Here is another source for the regulator SupplyCore Part Detail - NSN 2920-01-038-5252 - REGULATOR AND RECTI it was $89.78, arrived within a week and is new.