MEP004A Voltage Regulator/Exciter BBQ

[McKeelo]

Hello again, ok picked up this machine and worked out a fuel pump issue. Engine runs good now and the unit is producing electricity. 130vac fro L1,L2,and L3 to L0. The 208vac measures 225vac to 230vac. Voltage adjust on control panel does nothing. I haven’t loaded it at all. I did find this box on the passenger side above the gen head. The transformer looks like it got extremely hot and there are a couple leads broken off the transformer as well as two wires disconnected from what I’m believe are small capacitors. Inside of the cover is blackened as well as the edge and f the printed circuit board. I’m not an expert but this looks like a problem. Where do I start here? Thanks.

 

[Scoobyshep]

I would say your voltage regulator is done. I know a couple of members here that have rebuilt the existing a direct replacement is difficult to find. There is an aftermarket option but it requires some skill to assemble.

Sent from my SM-S908U using Tapatalk

 

[McKeelo]

I would say your voltage regulator is done. I know a couple of members here that have rebuilt the existing a direct replacement is difficult to find. There is an aftermarket option but it requires some skill to assemble.

Sent from my SM-S908U using Tapatalk

Yeah that’s kind of what I figured. I’ll be looking forward to those notes you mentioned about modernizing the AVR on your machine. Thanks

 

[Scoobyshep]

I am following the design in this thread. https://www.steelsoldiers.com/threa...lacement-and-single-phase-conversion.219949/#

I have never used this process before, the one i did was alot more complex.

 

[McKeelo]

I am following the design in this thread. https://www.steelsoldiers.com/threa...lacement-and-single-phase-conversion.219949/#

I have never used this process before, the one i did was alot more complex.

Ok I’ll check this out. Thanks. I’ve been reading another me a different member was going. It looked like he used a new regulator and then replaced the entire control panel. Looked very interesting too.

 

[McKeelo]

Hey Scooby, I read through the thread you mentioned and I’m fairly certain I can handle the conversion. I have used the sx460 regulator in the past on some onan equipment. So my initial thought would be to use it here as well. Is there any specific reason folks are using the advr-054 instead of the sx460 that you know of? The cost difference between the two is significant, that’s why I ask. Thank you.

 

[McKeelo]

I’m thinking about trying to repair the old regulator that I have here while I ponder updating to the sx460. Can anyone here please verify the T2 transformer input and output. I have access to a good variety of transformers thru my work as an elevator repair man. I believe the input is 208vac but I’m having difficulty identifying the secondary output. I’m fairly comfortable with wiring diagrams in general but the diagrams for this are giving me a run for my money. Thanks.

 

[jamawieb]

Hey Scooby, I read through the thread you mentioned and I’m fairly certain I can handle the conversion. I have used the sx460 regulator in the past on some onan equipment. So my initial thought would be to use it here as well. Is there any specific reason folks are using the advr-054 instead of the sx460 that you know of? The cost difference between the two is significant, that’s why I ask. Thank you.

Ive converted several units over with the advr-054 and marathon se350 vrs. The sx460 would work fine. Two install options, 1st is to bypass the exciter box but you have to self excite the field with an external source. 2nd is the one i like, is leaving the entire exciter box and adding the advr-054. This only works if the original exciter box is still exciting the field at start up. This way you dont have an external source to excite the field.

 

[McKeelo]

Ive converted several units over with the advr-054 and marathon se350 vrs. The sx460 would work fine. Two install options, 1st is to bypass the exciter box but you have to self excite the field with an external source. 2nd is the one i like, is leaving the entire exciter box and adding the advr-054. This only works if the original exciter box is still exciting the field at start up. This way you dont have an external source to excite the field.

This unit is still exciting the field somehow, despite the fact that the T2 transformer is melted down. The generator produces electricity but it is a on the high side. I wanted to try just replacing the T2 transformer but I can’t seem to figure out the secondary windings. H1 to H2 looks like 208 vac but then it looks like I have x1, x2, and x3? I have been reading that the secondary should be 120vac but is that in reference to x1 to x2? What about x3? So in the meantime I am considering just using the newer advr. I’m just conflicted because I feel like the A11 I have is repairable. I have a transformer that I can can connect with a 208 input on h1 and h2 but I don’t know how to configure the secondary windings.

 

[McKeelo]

I can trace the wires following the diagram in the -34 TM but I can’t figure out what the T2 secondary windings should be set up for? Thanks.

 

[McKeelo]

Let’s see if I’m understanding any of this. Looking at the exciter drawing from the -34 TM I’m thinking that using the exciter portion of the A11 with a modern advr the connections would go as follows,

P11, A-B are the a/c voltage input wires
P11, E-I are the field wires to F1 and F2

 

[McKeelo]

Ok, here we go. I got a few parts and I’m almost ready to finish this up. Thanks to all the members before me that posted here regarding the same issues and fix. I still have the original A11 complete with a roasted T2 transformer. The C2 capacitor tests good with a standard fluke 87. I have no other way to test it. I don’t know how to test the scr’s so I moved on to the aftermarket. I’m waiting on a few more resistors to finish this up following the drawing posted by member peapvp, thanks again for that. My question here so far is what size fuses to run on the a/c incoming? I saw another build where a member used a double pole breaker rated at 63 amps. Seems a little much for the wire size that’s why I ask. Anyway I’ll keep updating as I get this finished up.

 

[Guyfang]

The reason the gen set was still exciting is because the initial excitation comes from the S9.

 

[peapvp]

Ok, here we go. I got a few parts and I’m almost ready to finish this up. Thanks to all the members before me that posted here regarding the same issues and fix. I still have the original A11 complete with a roasted T2 transformer. The C2 capacitor tests good with a standard fluke 87. I have no other way to test it. I don’t know how to test the scr’s so I moved on to the aftermarket. I’m waiting on a few more resistors to finish this up following the drawing posted by member peapvp, thanks again for that. My question here so far is what size fuses to run on the a/c incoming? I saw another build where a member used a double pole breaker rated at 63 amps. Seems a little much for the wire size that’s why I ask. Anyway I’ll keep updating as I get this finished up.

Nice job with the new A11 so far. We use 10 Amp Circuit Breakers, so 10 Amp no delay fuses will work too
Btw. your special relay box seems to be missing the bottom cover and is open?
The Push Button can be omitted and the wire from Push Button to relay connected to A5 / K 5 Terminal 15 for automatic excitation

 

[McKeelo]

Nice job with the new A11 so far. We use 10 Amp Circuit Breakers, so 10 Amp no delay fuses will work too
Btw. your special relay box seems to be missing the bottom cover and is open?
The Push Button can be omitted and the wire from Push Button to relay connected to A5 / K 5 Terminal 15 for automatic excitation

View attachment 946271

Thanks Peter, I’ll connect that to terminal 15 and see what happens.

 

[McKeelo]

The reason the gen set was still exciting is because the initial excitation comes from the S9.

Interesting, I have been puzzled as to how this thing was working at all with the T2 transformer in the condition it is in, but like I said the a/c output was there just running a bit high.

 

[peapvp]

I updated the wiring diagram for automatic excitation and single phase supply 208VAC to 240VAC

 

[McKeelo]

Thanks Peter, I’ll connect that to terminal 15 and see what happens.

Is that terminal 15, or 14?

 

[peapvp]

Interesting, I have been puzzled as to how this thing was working at all with the T2 transformer in the condition it is in, but like I said the a/c output was there just running a bit high.

Sometimes they look burnt but if the wingdings are ok then they will work until last smoke has come out off them

 

[McKeelo]

Is that terminal 15, or 14?

Scratch that! I see it on the updated drawing! Terminal 14, thanks.