DC Voltage reg ?

[Bill W]

OO3A DC Voltage reg ?

OK
After pulling the front cowl on my 003A to get to the VR, I noticed what I believe is the capaciter with a disconnected wire, From what I've read one wire should be run to ground and the other to the red taped wire on the terminal block..Right? Also when I go and replace the VR the bottom 3 wires only one is marked so I know where to hook that on the T block, how about the other two, does it matter?, please type slow cause I'm bad at electronics and thanks for any input

 

[Bill W]

P.S. does anyone know if 002a's and 003A (DC) stators are the same? I know the part# for the 003A is NSN2920-01-048-9075 (FWA3001) Can't find a # for the 002A

 

[Speddmon]

Yes, the stators should be the same for both generators.

When you replace the VR, the red marked wire is the critical one to get in the right location. The other two coming out of the bottom are the AC lines coming from the stator so it doesn't matter which position they are in.

 

[Bill W]

Thanks Speddmon
I read one of your older posts about testing the stator and mine grounds out so along with a VR I'm gonna have to go for a stator to or maybe just go buy a 24v 4amp charger and just plug it into the 110 outlet on the genset.

 

[coyote62ny]

try tom at gulf coast trucks he has parts for these sets i got a starter from him for 55.00 he tests parts on a gen set to make shure they are good and he is cheaper than others his phone numbers are office 281-422-3200 cell 832 -323-1445 if your stator is shorted i would try that first i had problems with my regulator and speddmon helped me out i got a new one from southern automotive they make them for the military but they only sell on ebay the new one was 125.00 . i was looking at your pics it looks like one end of the capicator is under one of the screws that mount the terminal block to the engine front plate thats ground the other end of the capicator goes to the bottom wire under the one with the red band on it if you get every thing else fixed and you get sparks when you put the cables on the battery your capicator is probably bad to test just take the wire off the ground screw keep it away from anything metal put the battery cable back on if no sparks the capicator is bad if it still sparks you have unwanted power draw hope this helps

 

[Bill W]

OK
went to my local Mil surplus yard today ( Shirleys ) and got a stator from another 003A for $85 ( I had to pull it ) I also took the capacitor from that unit, the capacitor had 50UF75V printed on it so I goggled it to find that these go for around $50ea Is there any way I can test the capacitors that I have to make sure their ok before putting one back on or do I just go with the checking to see if the batts spark when hooking up the terminals
Thanks for the Ph # for Gulf coast, Shirley has never been cheap but he is local and I was able to test the stator myself

 

[tennmogger]

You can get an idea if the capacitors are good by using an analog VOM to test them.

Set the VOM (volt-ohm-meter) to a fairly high resistance scale, like x100, and connect across the capacitor. Make normal positive to positive connection first. You should see a kick of the VOM then the needle should drop back toward zero. The rate of kick and decay depends on the capacitance, your meter's internal resistance, and what scale setting you use.

There are two failure types in a capacitor. 1st is loss of capacitance. If that happens then the VOM won't kick and decay, it'll just stay at zero (open circuit).

2nd failure is shorting. If that happens the VOM will show low resistance, and stay there no matter what resistivity scale you try.

With a good capacitor, once you get a needle kick and decay, you can reverse the leads to the meter and get another bigger kick and decay.

That test is simply charging the capacitor with the voltage used for the resistivity test, and watching the results. Reversing the leads then applies the cap's charge back to the meter, makes a big kick, then charges the opposite polarity.

Doing what I just wrote takes about 1/4th the time!!

I would test a capacitor by attaching it to my LCR meter, LOL.

Bob

 

[Speddmon]

The numbers 50uF and 75v are the microfarad "uF" rating of the capacitor and the voltage rating of 75 volts. That capacitor should be nowhere near $50. You should be able to pick up a 50 uF 75v cap for less than $5.00. It doesn't have to look exactly like the one you have on the generator, as long as the ratings are the same. Also, make sure you are putting it in correctly. A cap that size is probably an electrolytic type, and therefore are usually polarity sensative. Make sure you have the negative side grounded and the positive side on the terminal strip with your red marked wire.

 

[Bill W]

OK
If I set the meter for continuity the horn will give a brief chirp then show open ( I think I'm saying it right ) it then won't do anything until I reverse the probes and then it'll chirp again then go to open ....is that good....It won't do anything on other meter settings with 400 being the lowest, on continuity it will sound at 50 ohms or lower

 

[PeterD]

OK
...( I had to pull it ) I also took the capacitor from that unit, the capacitor had 50UF75V printed on it so I goggled it to find that these go for around $50ea Is there any way I can test the capacitors that I have to make sure their ok before putting one back on ...

Two things on the capacitor. First, I have a lab grade capacitor tester and I'd be glad to test it for you if you want... Only takes a few seconds.

The second thing is that an old style analog VOM works well for testing of the cap's general condition. You connect the cap to the ohms leads, and it should swing to a low resistance value, and slowly (a second or so) swing up to a high resistance value. The speed of the swing up gives a very rough indicator of the capacitor's value but experience is necessary (or a known value) to be able to be sure about what you are seeing. Just look for an initial very low resistance that swings high while the leads are connected.

 

[Bill W]

Ok
I found a old cheapy analog meter I had in my truck so I tested the capaciter and it spiked and then went to open so I put everything back together which included my new to me stator and a NOS Volt reg ( sandblasted and painted the blower while it was off ) went to hook up the batt and it sparked sooo I disconnected the capacitor and had no spark when I reconnected batts anyhow Batts were showing 25.5volts and after starting and running genset for around 5 minutes charging went up to 26.6volts and still climbing when I shut it down so I think I'm in business. Now I looked through a Onan 10 DJC parts manual I have and they don't show a capacitor on the ( 12v ) civie model so I'm wondering how important it is and will it do any damage not using it
ANYHOW besides that its up and charging and I want to thank everyone for their help

 

[PeterD]

A quick spark when connecting is normal, that's the capacitor charging.

26.5 volts is a good charging voltage, anything between 26 and 28 volts is fine for a 24 volt battery system.

Sounds good!

 

[Bill W]

"A quick spark when connecting is normal, that's the capacitor charging."

Heck I thought that was bad when it sparked
Is it possible to put the capacitor back on further down the line being I have the A.S.K back on makes it a PITA to remove it all again to get back to the regulator

 

[Speddmon]

You can locate the capacitor or the voltage regulator anywhere you would like as long as they are hooked up properly. The reason the regulator is where it is, is because of the cooling it gets from the fan on the back of the engine. While it's only a 6 amp charging system, once the batteries are full that 6 amps has to be dissipated in the form of heat since the batteries don't need it any longer.

If you move the stuff, just make sure you can cool the regulator off. The capacitor doesn't necessarily need cooling, but the regulaotr most certainly does.

 

[Bill W]

I have no intention of moving the reg but I was thinking of tying in the capacitor to that harness wire that runs under the cowl that it would normaly attach to at the term block

 

[dfullerpt]

I have a problem with our MEP003A and found this post which I hope answers our problem.
We had our generator shutdown the other day after running great for 7 days. Went to restart it and batteries would not crank the meter showed low voltage. I put a meter on them only getting 21 volts. So further investigation led us to the VR as in this post. The 50UF75V capacitor appeared to have come loose but ours had spliced leads attached to it. While all apart and after charging batteries I restarted the unit and everything was fine. Here is where I screwed up when putting fan cover back together I did not notice that I pinched a wire and when attaching battery I created a direct short the wire on terminal board which runs all the way to TB4-6 in the control panel shorted and burned the whole way.

I separated the wires all the way to the panel and terminal board and saw no other damage, tested every wire and connection with meter and all the others appear and test OK. I ran a new 16 gauge wire from the terminal board back to the VR although the resistor is bad, and assume VR as well and will need to be replaced. I cranked over the gen set but it will not fire. Fuel pumps kick on, pre-heat relay kicks in I am not sure the start relay is kicking in and I did not want to jumper a wire to its terminal location because I am now gun shy I will short something else or damage something.

Question is should the gen set run without the VR and or resistor. readings the tech manual there is only a short section on engine cranks bit does not start. Nothing mentions the VR for charging the batteries.

Any thoughts

Dennis

 

[Speddmon]

yes, the set should run without the VR in place as long as the batteries hold a charge.