Electronic Parts Replacements Info for the MEP-802A

For those of you that need a quick replacement for a defective S1 switch, you may want to consider trying a similar one but not an exact version. Presently on ebay, there is a NOS switch for the MEP-805B that is listed which has 4 of the 5 functions of the MEP-802A S1 switch.

A push button switch for the "PRE-Heat" function would have to be added to the front panel. Therefore drilling one hole is required.

There is no screw on #2 position, so the #2 wire would be added to any of the 4,6,8 common bus wires.

I bought the switch just to replace a broken shaft. It is listed for $16.99, shipping included.

NOTE: I have not done this mod because I already have refurbished two S1 switches, so carefully review all requirements and details before proceeding.

KRAUS & NAIMER CHR10 C57410EF BLUE LINE ROTARY CAM SWITCH *NIB* NSN5930014989903

This switch has nothing to do with the MEP-805B. I just looked it up, and it is not listed in the parts manual. I suppose you could make it work, but the seller is not a "Truth in Advertising" candidate. The switch listed in the parts manual is: Part number C10-C57410E, NSN: 5930.01-368-5161, the same switch listed in every MEP-8XX gen set.

No power. Mep-802a. Bad relay k1

After trying to find the reasons I wasn't able to get one of my MEP-802As to produce power reliably (other than from the 120V outlet) I finally traced it to a bad K1 power relay.

None of the fault lights would come on, yet I could not get the actuator switch S5 to drive K1 all the time. Finally I ran out of things to check and took K1 apart, and to my surprise it has badly rusted, even though it has a rubber gasket. I have no idea how moisture got in.

I have had this MEP for a few months and it came with water in the exhaust since there was no exhaust flapper, but aside from a missing side door and front cover, there is no reason for water contaminating K1.

Not sure if it will be possible to find a replacement, but for now I will try to rebuild it or get a similar relay (though not an exact replacement).

I will be paying close attention to other MEP parts for similar issues.

KB3BF,

This is a failure that I would call typical, but it's not REAL common. The K-1, and I mean on ANY generator set from the MEP-004 up to the MEP-806 has a very similar type K-1. The rubber gasket was a problem 30-40 years ago, and is still one now. In the old days, we could replace the contacts in the relay, and the parts manual showed the guts, but it was simpler to just get another one. This relay is a commonly used one in the army. There are air con and heaters that use similar relays. So you ought to be able to find one.

In the late 80's and early 90's, we had so much trouble here in germany because of the high humidity and lots of rain, we took the relays apart. Then set them in my oven, at a VERY low temperature and dried them out. The we took RTV-159 and sealed them up again. We had lots less failures. Yours looks like someone pressure washed it, and lots of water filled it up. It stood a long time with water in it. This could not have happened from rain.

6110-01-367-8921 is the NSN, plug it into your browser. I think you will find one easy. Maybe not cheap.


Below is a link to an interesting article in P.S. magazine about the K-1 relay.

https://halfmastpsmag.wordpress.com/2012/12/03/5-10-15-kw-tqg-contactor/

I know that thing looks pretty knarly, but you might be able to clean it up with some red scotchbrite. I would expect the contacts to be brass, silver coated or possibly even gold coated. That should clean up. If you can get the crud out of it so mechanically it can move, then you might be able to save it.

Below is a link to an interesting article in P.S. magazine about the K-1 relay.

https://halfmastpsmag.wordpress.com/2012/12/03/5-10-15-kw-tqg-contactor/[/QUOTE]

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OK Guyfang,
so K1 is prone to leaks. I thought it was my fault since I did not put a bead of silicone everytime I remounted the MEP top panels. While I did not pressure wash the units, we had ridiculous long streaks of rain for months here in the Mid Atlantic region. I should have used a tarp to cover both MEPs until completed.

I temporarily removed K1 from the other MEP and checked its insides. It looks as brand new as first assembled at the factory, so this seal held up well. Both MEPs are from 1994, one with 1200 hrs (bid $1250) and the other with only 20 hrs (bid $411). Both are from GL Surplus, Mechanicsburg Pa.

While I will be looking for a K1 replacement, I am going to assemble three solid state 40Amp 240V on a heat sink and a small relay to handle pins 11, 12. (I will use 50 Amp if I find 3 of them or a three phase unit, but for now I have 40 Amp on hand).
If it works I won't worry about a rubber seal leaking (but for the small relay I will use one that comes in a sealed container).

I ran the second MEP at 100% load for a couple hours running between 5-6KW. Somewhere above 6KW it dropped below 60Hz and tripped. The smoke cleared after a few seconds under normal load around 80%.
For the sake of showing the load i built using heating elements, I am violating electrical safety rules until a get a front screen, and that will be addressed next. The homebuilt load came in handy (it does have a fan to blow air through the heating element). I gutted an old RF generator and used the case to house the load.

It's been a long journey getting the generators working, but well worth it.

Unfortunately the other MEP still has a problem shutting off, due to a damaged shut off lever, and the other MEP needs a door, but that's another story and another day, but we are ready if we lose power.

87Nassaublue said:

I know that thing looks pretty knarly, but you might be able to clean it up with some red scotchbrite. I would expect the contacts to be brass, silver coated or possibly even gold coated. That should clean up. If you can get the crud out of it so mechanically it can move, then you might be able to save it.

Click to expand...

Thanks for suggestion. I am trying to free up the solenoid but even after soaking it for some 12 hrs in a rust cleaner solution it is not working.
I'll look into red scotchbrite (I am not familiar with it) and find out where it can be obtained.

One other plan is to use the case (K1 gutted) and mount 3+1 solid state relays on the walls and see if that works, if not I'll look for a 3 phase 50 Amp relay/contactor that can be driven by 24V DC .

Nsn

Guyfang said:

KB3BF,

This relay is a commonly used one in the army. There are air con and heaters that use similar relays. So you ought to be able to find one.

6110-01-367-8921 is the NSN, plug it into your browser. I think you will find one easy. Maybe not cheap.

...............................................................................................................................................................................................................
Thanks for the NSN. You beat me to it.
Besides the parts sources you provided and are listed here, I also found this website:
http://docslide.us/documents/5kw-tactical-quiet-generator-24p-technical-manual.html

While I found a used one on Ebay for $370, it is too pricey.
http://www.ebay.com/itm/MILITARY-TQ...8-21066-MEP-802-803-804-805-A-B-/221822681280
I am going to keep looking just in case something comes up.

Click to expand...

I am providing some info on the load I assembled to test the MEP-802a.

Without a stable load it is hard to check the MEP. I did not have enough toasters, heaters and high intensity lamps to provide a 6KW resistive load.

The load uses two ~6KW GE heating elements, the types used in backups for heat pumps.
Each element is about 9 Ohms and can be wired as a single element for 6KW, or two in series for 3KW.

A fan keeps air flowing and is powered separately using the MEP 120V outlet.
The image shows the load wired for 6KW using one element.
Adding a 300W lamp provided the maximum load the MEP could handle (6.3KW).
Adding a second 300W lamp dropped the frequency to 40Hz and tripped the circuit (6.6KW).

I will be mounting a metal screen front and back to the case.
The load is grounded to the MEP, and both MEPs are connected with a 6 gauge ground wire to the house ground rod.

kb3bf said:

Thanks for suggestion. I am trying to free up the solenoid but even after soaking it for some 12 hrs in a rust cleaner solution it is not working.
I'll look into red scotchbrite (I am not familiar with it) and find out where it can be obtained.

One other plan is to use the case (K1 gutted) and mount 3+1 solid state relays on the walls and see if that works, if not I'll look for a 3 phase 50 Amp relay/contactor that can be driven by 24V DC .

Click to expand...

I believe you can buy the red scotchbrite at the grocery store in the section where they keep pot scrubbers. I know you can get the milder green scotchbrite there. You should be able to get it at home depot in the paint section also. I know you can get it at the autobody supply dealer. I bought a large box of it years ago for prepping cars for paint. When I was in the x-ray service business, the film processor guys used it to clean the rollers in the processors. The field engineers always kept a piece in our tool bags for polishing relay contacts. I still keep that stuff around, 30 plus years later. It makes a good pot scrubber, good to prep something for paint, good to clean grimy things with paint thinner or just polish relay contact. It never wears out. It just eventually disintegrates after years of use. There's just some things you can't improve on.

Oh, one other thing that might help you is Zepreserve. That is the best rust penetrating oil ever. It will free up things you'd think are impossible. I also started using that right after college. It's not easy to get and it's about $11 per can, but believe me it's worth it. The cans are large and last a long time. I have to buy it off the web or ebay these days. That's might help free up some of your close tolerance items. The last I bought was like 5 years ago and I'm almost out again. I keep a can handy all the time for such things.

Hi
thank you for the info provided.

I will check out both the red scotchbrite and Zeppreserve.
I am wondering one can soak the copper enamel coil too, but that is the least of the problems since it can be rewound if needed; I will report back with what I find out.

I forgot to ask is ZEP and Zeppreserve the same thing?

Hi Guyfang

(RRR)
would you know if K1 has contacts ratings at 240V, of at least 50Amps ?
I can't find an amperage spec.

If I am running the MEP at 120V, I would need a 50Amps contacts ratings.
If at 240V, 40 Amps contact ratings should suffice.

K1 maybe even higher than this.

Hi 87Nassaublue
i found and ordered a can of Zepreserve on ebay
http://www.ebay.com/itm/282075356541

So far the solenoid remains still frozen rust wise.
I hope Zepreserve works. we shall see.

I just found the amperage rating for K1, a wopping 150Amps!

see page 50 psmag for info on K1:

http://psmag.radionerds.com/images/7/70/PS_Magazine_Issue_726_May_2013.pdf

kb3bf said:

Hi 87Nassaublue
i found and ordered a can of Zepreserve on ebay
http://www.ebay.com/itm/282075356541

So far the solenoid remains still frozen rust wise.
I hope Zepreserve works. we shall see.

Click to expand...

LOL, I just ordered 5 more aerosol cans from the guy on ebay for $10 per can plus $15 shipping. I was almost out of the stuff. I tell you what that stuff works miracles on rusted and/or frozen hardware. Spray it and let it set a few minutes and then start working it and I bet it will free up. I doubt it will hurt the copper windings. After you get it cleaned up you can blow it out and let it dry good and it should be ok, if the windings weren't bad in the first place.

Here is a summary of what I did to get my second MEP-802A (year 1994, 17 hrs) operational:

replaced a water damaged K1
rebuilt and cleaned S1. THAT WAS FUN!
replaced S7 due to broken shaft.
removed water from engine
flushed the coolant system until it ran clean (about half a dozen times). Initially I used vinegar plus water.
changed the oil and filter twice.
added 6 missing relays and built S14 from scratch
replaced a leaking exhaust gasket
drained and cleaned the fuel tank.
replaced 2 missing bolts and nuts for the engine and generator mounts (looks like someone tried to remove the engine/generator, and then gave up).
added a missing 80V MOV and 2 bipolar diodes.
added a 3 amp fuse to protect the AC voltage regulator. Added a 150V MOV pins 7,8.
added two 12V batteries.
added new 4mm fuel return lines.
built an exhaust flapper, and one top cover.
build a 6KW test dummy load.

I still need to build a missing door, a front instrument cover, and paint the new parts.
Purchased 3 round door/latches for the door/panel.

During bidding I noticed most others ignored this MEP because of missing parts and poor overall looks. In reality it is in much better condition that I expected.

So poor looks can often hide other potential good attributes. My intention was to get it for parts only so I bid accordingly, instead I ended up getting a functioning generator with minimal $$ outlay (lots of labour, but worth every hr as a learning curve). Maybe there was some sporting event the last bidding night on Cable/TV which distracted many potential bidders from bidding.

And last but not least: many thanks to lots of great advice and help from the many members of this community that have posted valuable info.

GOOGLEPLEX THANKS TO ALL OF YOU!

Wow, that laundry list sounds like what I did to get my 016B going. Sounds like you did good on that one. Oh by the way, you mentioned cleaning the cooling system. I found a product that does an in credible job on that. There's an individual guy up north that makes it. I've spoken to him on the phone and he won't divulge what this stuff is. Since they outlawed the old Dupont No. 7 cleaner, this is the only thing I can find that does a great job. I have some at my other house. I'll get the weblink off one of the bottles tomorrow and post it. I'm sure you guys will appreciate this one.

Hi 87Nassaublu
i would be interested in that website too, but my concern is that if he wont say what chemical are made of, is the cleaner safe for the engine?
That's why I used vinegar and not baking soda, but one could test it on some metals and see what chemical reactions take place and how strong they are.
Even with vinegar I got a lot of scaling removed with abundant brown foam, so at least it was doing something.
Then I would run it until it reached normal temp before waiting to flush again (after cooling), hence a slow tedious process taking up most of a day.

I have the other MEP to finish flushing also and if I can do it in half the time that would help.
When both MEPs are ready I will use the John Deer coolant as recommended here.

By the way I found a 50 Amp replacement for K1, or at least I thought so. While the contacts are rated for 480V AC, the coil is 24V AC, not DC.
When I hooked it up to a DC power supply it drew 1.8Amps at 24V, but only 0.6Amps for 24V AC. Moral of the story you can't substitute AC vs DC coils because of the reactance difference. I had to drop the voltage to 7.8V DC to get the same current rating.
So I am back looking for a replacement for K1.