MEP-003A No Output Voltage

[ckesey]

I've had my MEP-003A running producing voltage until tonight. I noticed a few days ago it was slow to turn over so I checked the batteries and they were low. I disconnected them and changed them one at a time. I hooked it all back up and started as it should. I ran it to begin troubleshooting the DC charging system and noticed that all the guages were to the far left. I checked and had no output on the outlets.

I have checked the breaker next to the run switch and its got 25v to each side. I've shutdown and started it several times holding it in the start position 10-20 seconds after the engine ran but that doesn't seem to change anything. I've changed the position switch to 3ph and checked output of all legs and have nothing. I've also cycled the breaker several times with no change (if I remember correctly I should still read voltage and Hz when the breaker is open).

I've read several posts here about no output but I'm a little overwhelmed as to where to start.

 

[ckesey]

I did smell a burnt smell coming from the AC output box. Upon further inspection, I found a black pile of something charred sitting on top of the CVT1 on the far right side. Ive moved the wires around and can't see where has come from. All the wiring in that area (after I racked off the charring) seems to be intacted.

 

[Triple Jim]

I did smell a burnt smell coming from the AC output box. Upon further inspection, I found a black pile of something charred sitting on top of the CVT1 on the far right side. Ive moved the wires around and can't see where has come from. All the wiring in that area (after I racked off the charring) seems to be intacted.

That could be a big clue, so it's probably worth a very close look at what that burned material came from.

 

[Guyfang]

Could have been a critter. Or a nest. Not important now. Unhook all the C-Plugs and unbolt the AC output box. take it to a work bench and start cleaning/checking it out.

Have you downloaded the TM's?

 

[ckesey]

Could have been a critter. Or a nest. Not important now. Unhook all the C-Plugs and unbolt the AC output box. take it to a work bench and start cleaning/checking it out.

Have you downloaded the TM's?

Could have been a critter. Or a nest. Not important now. Unhook all the C-Plugs and unbolt the AC output box. take it to a work bench and start cleaning/checking it out.

Have you downloaded the TM's?

Yes I have the -34 and was reading studying it last night. There are several procedures that allow you to test various components. Where I was stuck was getting started. Wasn't sure what I should be testing first. I'm not terribly familiar with these units (especially the electrical). Without knowing the components and how the interconnect, I was picking something and then following the test procedure.

Is there anything in the TM that gives troubleshooting process , IE test/inspect this then test/inspect this.

 

[Guyfang]

Start on page, (PDF reader page #) 87 and read to page 103. There is the whole AC output box test and repair there, in the -34. You really need to find out what burned, and inspect the components.

 

[ckesey]

I've pulled out the AC control box and did some inspecting and I can't find any wiring that is burned. Several wires have heavy char marks on them when I scratch on them it comes off. There is evidence of a nest and fine bedding material is laying across several terminals (mostly the CVT1 and the CT) I'm wondering if the bedding material is what has left the char marks after laying across some of the terminals and burned/melted until it shorted something out.

Moving on to testing.....I've been following the TM and found some things that doesn't seem to be testing correctly and wanted your opinion.

#1 the linear reactor in the back corner of the box....does it count terminal 1 closes to opening through terminal 6 at the back? I couldn't find a diagram of how the terminals laid out. If so I have 2 ohms across 1 & 2 (2 pins closes to box opening) but megaohms between 3 & 4 and 5 & 6 (back 2 pairs).

#2 when testing the CVT1 I have an open between H5 & H6. All other primary and secondary tests within what the TM calls for.

I didn't move on from here after seeing both of those components testing abnormal.

To be clear all of these test were done with the AC control completly disconnected from genset laying on a table. These test are suppose to be done with the box disconnected correct?

 

[Guyfang]

I've pulled out the AC control box and did some inspecting and I can't find any wiring that is burned. Several wires have heavy char marks on them when I scratch on them it comes off. There is evidence of a nest and fine bedding material is laying across several terminals (mostly the CVT1 and the CT) I'm wondering if the bedding material is what has left the char marks after laying across some of the terminals and burned/melted until it shorted something out. (Very possible. But you need to check everything out with an eagle eye.)

Moving on to testing.....I've been following the TM and found some things that doesn't seem to be testing correctly and wanted your opinion.

#1 the linear reactor in the back corner of the box....does it count terminal 1 closes to opening through terminal 6 at the back? I couldn't find a diagram of how the terminals laid out. (Look at the wire number on the schematic. Then you know for sure what is what. The wire to terminal 1, on the L1, is X38A18. When we talk about wire numbers here, we omit the last two numbers, as they represent the wire gage. So it should be wire# X38A.) If so I have 2 ohms across 1 & 2 (2 pins closes to box opening) but megaohms between 3 & 4 and 5 & 6 (back 2 pairs).

#2 when testing the CVT1 I have an open between H5 & H6. All other primary and secondary tests within what the TM calls for.

I didn't move on from here after seeing both of those components testing abnormal.

To be clear all of these test were done with the AC control completly disconnected from genset laying on a table. These test are suppose to be done with the box disconnected correct? (Correct. Or you will be reading through other components.)

 

[Triple Jim]

when testing the CVT1 I have an open between H5 & H6.

That alone means CVT1 needs to be replaced. That open winding means one phase of the tranformer's exciter field output will be missing.

 

[ckesey]

Will that keep from getting any output (single phase or any of the three phase legs)? Anyone have a lead on where I can get a CVT1? Having a hard time locating one online.

 

[Triple Jim]

Will that keep from getting any output (single phase or any of the three phase legs)?

I haven't experienced this, but my guess is that is would cause low output voltage, not zero output. This is one of those "It's definitely a problem, but maybe not the only problem."

 

[Guyfang]

Partner, your wasting time. Take the components out, test them, and then you know what you need to do.

 

[ckesey]

Partner, your wasting time. Take the components out, test them, and then you know what you need to do.

Yes I have removed everything from the box and have tested everything. I have two bad components. The CVT1 has an primary winding that is open as well as the linear reactor transformer (middle two and rear two terminal pairs) are reading mega ohms.

Anyone have any advice on locating another CVT1? Looks like the transformer I can purchase on eBay but having a hard time finding the CVT.

Thanks for any help

 

[Guyfang]

Saw the Whole AC output box in epay. GMG. But for that price, I could drink beer for 10 years.

 

[ckesey]

Saw the Whole AC output box in epay. GMG. But for that price, I could drink beer for 10 years.

I saw the same thing. An easy plug and play solution but for sure not cheap.

Could these be repaired? I've talked to a company that claims they can but I'm a little leery.

 

[Guyfang]

Yes. Transformers can be rewound.

 

[glcaines]

Have you checked with Delks? http://www.delksarmynavysurplus.com 336-629-0991

 

[Ray70]

Swapping out the entire AC reconnect box is much easier than wrestling with the wires through the CVT to the switch, but for what they want for one you can buy another whole parts machine cheaper.
Chris, if you want to verify the AC reconnect box components are the only issue, when you come up to work on your other IP I have boxes we can swap if you want to test this machine with a known good box, ( if you want to bring both machines ) but unfortunately I don't think I should part with my last spare.
I do have an extra CT and a linear reactor ( from a box I already sold the CVT1 from, just don't want to part out my last complete spare box.

 

[ckesey]

Swapping out the entire AC reconnect box is much easier than wrestling with the wires through the CVT to the switch, but for what they want for one you can buy another whole parts machine cheaper.
Chris, if you want to verify the AC reconnect box components are the only issue, when you come up to work on your other IP I have boxes we can swap if you want to test this machine with a known good box, ( if you want to bring both machines ) but unfortunately I don't think I should part with my last spare.
I do have an extra CT and a linear reactor ( from a box I already sold the CVT1 from, just don't want to part out my last complete spare box.

I think you have confused me for someone else. I would love to take you up on that offer but doesn't look like we are very close.

This generator was making power when I purchased it and it just stopped (not sure why these two components went bad at same time). I'm wondering if something made a nest that shorted something out but don't have any proof of that. Is there anything else that could be bad that caused these parts to tank? I don't want to spend the money on new parts only to short them out when I fire it up.

I'm going to talk to the company that reached out to be about repairing my CVT1. It's a long shot but I'm not coming up with any other solutions at this point. I called Delks today and didn't get an answer but will try again tomorrow.

 

[Ray70]

Wow, yea, wonder how I messed that up! Sorry about that, I confused you with another SS member ( a bit closer than TN ) with the same problem on one of his machines. Maybe I should stop reading this forum late at night and go to bed instead!