Problem with 002a AC meter

[Boatdoc]

Picked up a 002a with 1330 hrs yesterday that I won at the recent Ft. Polk auction. No problems at Polk or with GL. Enjoyed the experience completely. Got the unit unloaded yesterday eve and checked it out thoroughly. Residual fuel in tank and filters was very clean. Also oil on end of dipstick looked never ran. New air filter element. Wiped out tank and drained filters. Added fresh fuel,oil and batteries. Primed pumps and after tightening a couple of loose cable connections on starter, it cranked up after only 4-5 seconds. And of course, died immediately upon releasing the start switch (blame my complete lack of experience w diesel gensets) but thanks greatly to all the information on this site, I quickly remembered to hold the start switch until the engine had oil pressure and leveled out. It ran perfectly, adjusted perfectly and made power. I am very pleased w the unit overall. Every single component works except the AC voltmeter. Opened up the front panel and found one wire disconnected from back of meter and the remains of what appears to have been a wire coil resistor installed between the two terminal posts. The coil looks like it burnt out and there is a small fiber plate on back of gauge w signs of smoke on it. Assuming plate insulated gauge from the heat of the coil. I can find no reference to this coil anywhere in schematics, TM's or on this site. Does anyone know what this coil may have been or what it was installed for. The meters all appear to have been replaced and possibly it's used on newer replacement parts? Any and all advice welcome!

 

[rosco]

I don't know what the wire coil resistor does, is supposed to do, or if it is supposed to be there. Probably somebody else will chime in, with the answer. But my experience is this: on the 002 that I just got from GL here, with only 8 hours on it, there was no such resistor stuff on the voltmeter terminals. The set, when fired up, ran flawlessly, and powered much of my shop, including the well pump (1.5 hp) cycling, with what looked to be almost 8 KW on the percent meter. Anyway, the volt meter ran, for a while and failed. I called Delk's in NC (336-629-0991), and talked to William and he said that while the set is running, test for Voltage at the guages terminals with a meter. If it has voltage and the guage and is not working, the guage is NG. He did not mention any resistors, the guage needed. Check classifieds here, if you need parts. It wouldn't hurt to set the valves in your genny too, just for good measure. One of my exhausts was a little tight, and I could hear that, in startup. Good Luck & BTW Welcome to the site.

 

[rosco]

I just checked my 003 - there is no resistor on the terminals on its volt meter either.

 

[Boatdoc]

Thank you, Rosco. I think I'm gonna hook the wires back up and try it without the wire coil tomorrow and see what happens. It can't hurt anything because obviously it was running when the coil burnt. I do feel like the coil was put there for a reason, this being a Army generator straight from GL. The only purpose I can see it serving would be to smooth out the the electrical pulses to the gauge to prevent needle flutter. But that's only a wild guess. I just got in from taking the kids to the local fair (fun fun) and its too late tonite to wake the neighbors to test the gauge. But I did go out and took a closer look at the coil. It is small. Slightly larger than a ball point pen spring w what looks like originally 8-9 coils of wire. The odd thing is that it's not crimped or soldered to the spade terminals that go over the posts. It has tabs that stick out about 1/4" w small holes in each and the wire coil is actually looped through the holes on each side like you would install a spring. I can verify that it was there between the two posts because one side w burnt wire is still installed under gauge wire and smoke from the coil burning is very evident on the back of the gauge. Maybe someone on here will see this and know what it was and if it's needed. Thanks again guys.
Aaron

 

[Isaac-1]

Keep in mind these are not direct reading AC voltages gauges like so many modern ones are instead they use a CVT coil for the voltage sensing. This technique is still commonly used with higher voltage gauges, but rarely on 120-240VAC stuff. Sorry no help on the coil here either, although I will say my MEP-002a voltage gauge jumps around so much as to be hardly useful for anything other than showing the presence of voltage. As you may suspect by now vibration induced problems are common with these sets.

Ike

 

[Boatdoc]

Finally had time today to run the genset with the AC meter hooked back up. No big surprise the meter works perfectly without the coil installed. Compared readings against my fluke. Dead on at 120 and only reading a few volts low at 240. Now it's anyone's guess why somebody unhooked the gauge after the coil burnt out if it was still working, or why the extra part was ever installed in the first place. But regardless, it's working now, and other than one very small fuel leak through one hose, it appears that I got a very good 'runner'. Thanks again to Rosco, Ike and all others who took time to read this thread.
Aaron

 

[storeman]

Shade tree mechanic....Congrats on a working unit!
Jerry