MEP-803a overload circuit

[novaman]

Update

UPDATE

Since im inpatient i couldn't wait for the deoxit to come in the mail. Since i have 2 other running units sitting next to it i swapped S8 from another unit. And it worked! Now that its out you can see the contacts are completely visable from the sides of the switch should have looked at it better before doing all that work. Im thinking getting a thin popsicle stick and put like 2000 grit sand paper on the tip and just run it between all the contactors. Again that could have been done without removing it!

How ever i have a challenge for the crowd.

Put your unit into 3 phase. Now put a single phase 240v 8kw load from L3 to L1. What is your voltage from L3 to N and what is your voltage from L1 to N?

Like i said i have 3 units all of them drop voltage from 120v from L1 to N to 112v while the other 2 legs keep 120v.. Y?

Why does L1 have voltage drop? The gen head is wired y it should be the most balanced configuration on the gen head.

 

[Guyfang]

This is why CECOM demanded a new S8. There is no telling how old your switch is. If I remember right, the S8 is a mandatory change item, during reset. But that doesn't always happen. Also, some resets that I saw happen, Often had people taking parts from one pile of parts, and using it to get another done. Getting jobs out of shop presents a lot of pressure on personnel to close jobs. So sometimes the product isn't always the best.

 

[DieselAddict]

UPDATE

Since im inpatient i couldn't wait for the deoxit to come in the mail. Since i have 2 other running units sitting next to it i swapped S8 from another unit. And it worked! Now that its out you can see the contacts are completely visable from the sides of the switch should have looked at it better before doing all that work. Im thinking getting a thin popsicle stick and put like 2000 grit sand paper on the tip and just run it between all the contactors. Again that could have been done without removing it!

How ever i have a challenge for the crowd.

Put your unit into 3 phase. Now put a single phase 240v 8kw load from L3 to L1. What is your voltage from L3 to N and what is your voltage from L1 to N?

Like i said i have 3 units all of them drop voltage from 120v from L1 to N to 112v while the other 2 legs keep 120v.. Y?

Why does L1 have voltage drop? The gen head is wired y it should be the most balanced configuration on the gen head.

You are going to make a contact burnishing tool. Use the finest grit stuff you can. The idea is to clean the contacts but not remove material from them. Be gentle.

How are you measuring the voltage differentials? On the output terminals with a meter or via the internal gauges?

Having some voltage imbalance in a system like this isn't unusual. Coils are never perfectly wound to their theoretical best configuration so we should always expect and accept some deviations.

 

[dav5]

Well again I learned something new. I thought the contacts were internal rotary contacts and couldn't be accessed directly and could only be cleaned with contact cleaner.

 

[Guyfang]

Even old dogs can learn. But let's wait until he is done to see how it goes.

 

[novaman]

Im using a fluke mm to measure the voltage differential. The volt gauge showd the phenomenon too. Also all three of my units do it. Yes ill be using 2000 grit wet sand paper or even emery cloth. Problem with cycling is its not sweeping the contacts accros each other just opening and closing them doesnt brush off the corrosion, grit or spider carcass thats on the contactor. So im going to use deoxit and be really gentle with the cleaning one or two passes with emry cloth should be enouph. I think it a poor design being open to the outside like that. This unit was kinda sandy and dusty so om guessing theres a piece of grit/dust in there somewhere

 

[novaman]

Even old dogs can learn. But let's wait until he is done to see how it goes.

Might take a few days for the deoxit to show up via online order

 

[novaman]

This is why CECOM demanded a new S8. There is no telling how old your switch is. If I remember right, the S8 is a mandatory change item, during reset. But that doesn't always happen. Also, some resets that I saw happen, Often had people taking parts from one pile of parts, and using it to get another done. Getting jobs out of shop presents a lot of pressure on personnel to close jobs. So sometimes the product isn't always the best.

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

 

[novaman]

This is why CECOM demanded a new S8. There is no telling how old your switch is. If I remember right, the S8 is a mandatory change item, during reset. But that doesn't always happen. Also, some resets that I saw happen, Often had people taking parts from one pile of parts, and using it to get another done. Getting jobs out of shop presents a lot of pressure on personnel to close jobs. So sometimes the product isn't always the best.

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

 

[novaman]

Glitch in the matrix how the **** did i post that twice

 

[Daybreak]

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

Howdy,
I posted up a new thread with the MEP generator reset information

It's a good read.

 

[jamawieb]

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

My experience with tier 2 resets have been excellent. Pretty much everything is new; motor, generator head bearing, relays, all the switches, fuel pumps, etc. All the items that could wear out are replaced.

 

[Guyfang]

Read!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Look at Mike's Document!! Go to appendix K, for a look at MANDATORY REPLACEMENT PARTS!! Then you will see what should be new, and what should not.

 

[Guyfang]

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

By the look of the set, it might have just come back from deployment. And that's why it was slated for RESET. Read the RESET document. Its suposed to spit out a set as good as new. 99.9% of the time it does. BUT, if it says reset, it doesn't mean someone else hasn't screwed with it. Or it doesn't mean the set hasn't been run hard and put up wet. If you are going to get into this sort of thing deep, look for Mike's, (Daybreak) thread about fasteners. Go buy a shi* tree full, and start replacing them if missing or rusty/no good. Any set not directly out of RESET is suspect. Trust nothing, check everything.

 

[Guyfang]

This unit is a 2003 and theres only 2000 hours on ithe meter so im thinking s8 is why it was taged cecom, for repair of that OL fault light. I found s8 on ebay for like $140 so worse case scenario i fubar it ill buy a new one. What exactly is "reset" ive been avoiding tier 2 units like the plague. Ive read it means engine or gen head has been replaced. Then it gets a new meter so its hard to say how many hours its been beaten for. And evertime i see a unit missing screws its always a tier 2. I feel like ya it got a new engine or gen head but all the other parts are still worse for the wear and something else failed then someone tried "fixing" it in the field gave up and put the cover on with 3 screws and sent it to auction. Am i off base with my thoughts?

If you just have to get a new S8, try and get the new one.

You say "only 2000 hours". Soldiers are not famous for lavishing TLC on generators. "Run em till they break down" is more like it. You need to set down, and look at your set. Inspect it. Write up the faults. Fix everything that you can, and then start servicing. Then testing. You might be surprised! But get organized. Step by step. READ!!!!!!!!!!!!!!!!!!!!!! Get to know your beast. The TM, when someone takes the time to read them, will answer a kazillion questions.

 

[novaman]

Read!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Look at Mike's Document!! Go to appendix K, for a look at MANDATORY REPLACEMENT PARTS!! Then you will see what should be new, and what should not.

As you said earlier many units reused old parts from other units being reset just to get them out the door so the parts that "SHOULD" have gotten changed is where my concern comes from.

 

[novaman]

By the look of the set, it might have just come back from deployment. And that's why it was slated for RESET. Read the RESET document. Its suposed to spit out a set as good as new. 99.9% of the time it does. BUT, if it says reset, it doesn't mean someone else hasn't screwed with it. Or it doesn't mean the set hasn't been run hard and put up wet. If you are going to get into this sort of thing deep, look for Mike's, (Daybreak) thread about fasteners. Go buy a shi* tree full, and start replacing them if missing or rusty/no good. Any set not directly out of RESET is suspect. Trust nothing, check everything.

That's what I think too is it just came back from service and was tagged cecom to have that S8 repaired. I'm not doubting the reset is meant to make these things like new. I'm just saying every time i see a unit at auction with a bunch of screws missing from the covers as if someone gave up trying to fix it, its always been a teir 2 unit. I prefer run hard. I keep seeing run soft and the engines are all full of carbon and borderline wet stack. I stay away from those too. If I see a ton of the black death all over the exhaust manifold I know its hit. I've had a few that where just starting to seep the black death and I ran them hard till they cleared out and stop raining carbon on me and they where good to go. I've even done meth injection on one to clean it out. I think it did a great job but what a pain flushing the moisture out of the oil. I did it to turbo fans all the time to clean out compressor blades on motors that came from china. Ever take a head off a car with a bad head gasket that cylinder is usually the cleanest. I have a whole bunch of stainless fasteners for replacing missing or corroded ones.

 

[novaman]

If you just have to get a new S8, try and get the new one.

You say "only 2000 hours". Soldiers are not famous for lavishing TLC on generators. "Run em till they break down" is more like it. You need to set down, and look at your set. Inspect it. Write up the faults. Fix everything that you can, and then start servicing. Then testing. You might be surprised! But get organized. Step by step. READ!!!!!!!!!!!!!!!!!!!!!! Get to know your beast. The TM, when someone takes the time to read them, will answer a kazillion questions.

Every unit I get I pull the top cover off and look for apprentice marks. Loose wires, corrosion, sabotage and over all condition. Then i load them to 80% @1.0ph resistive heaters for 4 hours, 100% for 1 hour Same 1.0ph then use my variac to see how much she'll suffer till she drops RPM's. If it'll go to 133% then I'll do some surges to check the governor 0-100% 80-100%, 80-133% and 100-133%

https://www.youtube.com/watch?v=ovKYkicH3D0
https://www.youtube.com/watch?v=y357t8x-Qms

 

[novaman]

Still waiting on Deoxit What the F

 

[m32825]

Sounds like s8 reconnection switch with corroded contacts. You have to work it left to right sometimes 100+ times while spraying electrical cleaner to clean the contacts. Usually if a winding is shorted, you wont get any output.

Thank you for this post. My 803 was dropping out around 32A@240V during load testing with an oven. After cleaning and exercising S8 it sustained 48A@240V, everything the oven could give it, for half an hour until I ran out of daylight. Woohoo!

Now I need more load to see where it cries uncle. Going to see if I can persuade both oven elements to run at the same time.

-- Carl