Stuck Voltage Reconnection Switch on MEP-803A

[diogenescreosote]

I recently acquired an MEP-803A, which I wish to run in 120/240V mode, because I have both 240V and 120V loads. Currently, the generator is in 3-phase 120/208V mode.

When I tried to move the AC Voltage Reconnection switch, I couldn't get it to budge, even when I applied as much torque as I could with my thumb and index finger. I have attached a picture of the switch. I cannot find a section of TM 9-6115-642-24 that describes this problem.

Does anyone have insight into why it might be stuck? Also, what is the minimally invasive procedure necessary to unstick the switch, or, failing that, to get it stuck in 120/240V?

Much thanks in advance.



Has anyone seen this problem before?

 

[Zed254]

You are missing the knob on that switch. Also, you need to install the quad fuse before anymore run time to protect the generator windings. The two holes above the switch are missing some bolts......which means you need to get the top off so you can inspect the switch and that part of the control box. Contact cleaner might bring the switch back. I'm not sure what those missing bolts are attached to: may be the switch that someone was attempting to replace?

 

[diogenescreosote]

Thanks. I will spend some time studying that document about the quad fuse. Any idea why it might be missing, or what its absence suggests about the generator's history?

I just bought this thing about 3 runtime hours ago. During this time, I've put at most 5 amps at 110V on it via the convenience receptacles, so I suspect I haven't messed up anything yet. I'm glad I know about the missing quad fuse before I press this thing into 8 kW, 8 hours a day service.

 

[America]

Thanks. I will spend some time studying that document about the quad fuse. Any idea why it might be missing, or what its absence suggests about the generator's history?

I just bought this thing about 3 runtime hours ago. During this time, I've put at most 5 amps at 110V on it via the convenience receptacles, so I suspect I haven't messed up anything yet. I'm glad I know about the missing quad fuse before I press this thing into 8 kW, 8 hours a day service.

Maybe you just can’t grip it because of the broken off knob?

 

[diogenescreosote]

Maybe you just can’t grip it because of the broken off knob?

I dunno, I can put quite a bit of torque on it with just my fingers, well in excess of a foot pound. I suspect that its being stuck is what caused the knob to snap off.

 

[America]

I dunno, I can put quite a bit of torque on it with just my fingers, well in excess of a foot pound. I suspect that its being stuck is what caused the knob to snap off.

I’m a three hundred pound athlete and can’t turn it without the knob. It needs to be pretty stiff to make electrical connections. How about trying to turn it with some vice grips just to see. Use your best judgment not to force it. If it won’t turn take the top panel off and clean the switch. You can start with a penetrating fluid then once you get it to potentially move clean the switch with contact cleaner by rotating it back and forth will you rinse the electrical contacts. Go crazy with the contact cleaner. Lol idk that switch isn’t stuck I bet.

 

[DieselAddict]

Before you do anything else get the top off of it and inspect the entire area behind that switch. A missing knob and screws are big red flags.

Also the quad fuse is a modification that was performed later to protect the exciter windings from damage in case the voltage regulator fails. Later units shipped with it installed but many had to be modified in the field.

And +1 - you aren't turning that switch without the knob.

 

[Guyfang]

If your life hung in the balance, of turning that switch with no knob, you would be history. The S8 switch has some heavy duty spring action on it. Why? Because if contacts were weak, they can chatter. If that happens, there will be arcing. If that happens, there will be heat. If that happens, switch failure is just around the corner. ALSO, never, never, never turn S8, while the set is running. When the contacts open and close, you get these big fat arcs. See above, for what happens. Sometimes when people open and close switches, relays, contacters and such, under load, the damage is very interesting. When a set of contacts arc, a small amount of contact surface will be removed from one side of the contacts, and deposited on the other. When this happens enough, the contacts can stop conducting voltage. Or weld the contacts together. Then when you least expect it, like shutting off a switch, the voltage still flows from point A to point B. You think its turned off, and it isn't. Oh baby. That is not good for your ticker.

 

[America]

I would of took apart the genny enough to atleast inspect most of the components before trying to run it for any significant amount of time or load.

 

[Ray70]

Like everyone said, Best to see why it's been fiddled with and go from there. If the switch ends up being bad I have a used spare.

 

[Guyfang]

Here is a tip. Look around in the bottom of the set, in dark corners and where you would never look. Sometimes you can find these errant pieces. Knobs and things can still be there. Just got to look.

The problem with taking things apart, "just to look at them" is a two sided sword. Long ago, I learned to "Dont fool with it if it aint broke". Sound advice 48 years ago, and its still sound now. Certain things, like fuel lines, inspecting the fuel tank. Looking at a leak and chasing it down. those kind of things pay off in the long run. And only a fool would to pull the control cube top off, to take a look see in the AC portion. But taking it to bits and pieces, just to check everything? too much time. Make it run, then do the fine tuning. Having said that, there just aint nothing like tearing that critter down to the nuts and bolts and putting it back together. We were suposed tonot do engine rebuilds, as that drives down time through the roof. Engine swap. Yeah we did some engine work when we could kinda "hide" it. But the military lives and dies on operational readiness.

 

[diogenescreosote]

Also, you need to install the quad fuse before anymore run time to protect the generator windings.

Where would you recommend ordering the parts listed in the PDF you attached? I just heard back from parttarget.com, which doesn't want to do business with me because I am small fry.

 

[Zed254]

MEP-802 and 803 Main generator tip.

The MEP-802 and MEP-803, A1 volt regulators sometimes go bad. When they do, the Stator is often damaged. The troubleshooting diagram tells you to first test the stator. If you find that the stator is defective, naturally, you change it. So after installing the stator, you fire it up and presto...

www.steelsoldiers.com

Search the site for more suggestions.

Fuse: https://www.allfuses.com/fnq-r-3?msclkid

Search Ebay, too.

 

[Farmitall]

I dunno, I can put quite a bit of torque on it with just my fingers, well in excess of a foot pound. I suspect that its being stuck is what caused the knob to snap off.

It may well be stuck but you'd still not be able to turn it by gripping the shaft with your hands alone even if it were not stuck......they are pretty stiff switches.
I would inspect the contacts which are visible along the sides and see if any show signs of previous arching and do this before spraying them with contact cleaner so you don't wash away any arch residue that would tell a story. If you can find a corrct knob, use some finesse back and forth to make sure that one or more switches in the stack are not bound up. A lubricating cleaner might wash out any dust that has accumulated in the switch works.
Also, be sure the switch is mounted before running the set when that time comes.

I had one of my sets that that switch was badly corroded and had to replace it.

Keep us informed of your progress and ask questions if you need to......we are all here to help eachother.

 

[Daybreak]

Howdy,
Your best resource is right here.
There is a classified section. Someone might have a donor unit which you can buy pieces you want.

Quad Fuse parts = all parts needed can be found anywhere.
on PDF page 29

Military MEP generator reset information

Howdy, This Technical Bulletin has all the information regarding what happens to a Tier I and Tier II reset. It's a good read to understand what happens and what gets changed, inspected and/or replaced. Covers 2kw to 200kw

www.steelsoldiers.com

I see you live in the land of the Skunk Railraod.

 

[diogenescreosote]

I see you live in the land of the Skunk Railroad.

Indeed I do, though my parcel overlooks the abandoned NWP that ran N of Willits, not the Skunk Railroad itself.

I have so far tried to just use a vice grip to turn the shaft. No luck so far. Next up, opening the top, then probably contact cleaner.

 

[Guyfang]

If you need a new one, there are 4 in the Big Auction site. Something to remember, when looking. Always try ALL the part numbers, AND the NSN. All 4 came up when I checked the NSN, but only 3 came up when I used the two different part numbers, 88-21901 and the Kraus Naimer number, C26-C57442ER.

One of them was much cheaper then the other 3.

 

[Ray70]

I also have a used one I can part with, if you end up needing a switch.