MEP 003A Alternator Voltage Regulator Wiring

[Floydla1]

Hello Gents,

My 003A is not charging the batteries. The resistor required to test the circuit cost almost as much as the voltage regulator, so I found a regulator on eBay. Now, I cannot find a schematic in the manuals to show me how to wire it up. Basically I need someone to help correctly connect wires 1 and 2. Routing the other wires is simple since #3 is marked red, and A and B wires are routed to the fuse. Please see my diagram. I appreciate your help very much.

 

[Mullaney]

Hello Gents,

My 003A is not charging the batteries. The resistor required to test the circuit cost almost as much as the voltage regulator, so I found a regulator on eBay. Now, I cannot find a schematic in the manuals to show me how to wire it up. Basically I need someone to help correctly connect wires 1 and 2. Routing the other wires is simple since #3 is marked red, and A and B wires are routed to the fuse. Please see my diagram. I appreciate your help very much.
View attachment 873733

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Hi Floydla1

Hate to admit that I have no clue how to help you - but there is a lot more traffic on the Generator Forum and folks who will be able to offer up some suggestions. I made a request to have this post moved. Hopefully that will help.

Tim

 

[Light in the Dark]

Is the defective one still in the machine? Should just be able to see how the wires come out of the Alt VR and put them to the same TB locations?

 

[Light in the Dark]

I think this is what you are looking for? From the -34. G2 is the Batt Charge Alt. Has the wire numbers with TB positions.

 

[Ray70]

If I recall correctly, wires 1 and 2 don't matter as far as orientation because it it AC voltage coming into the regulator. You may find more info in the charging circuit sticky at the top of the Generator forum.

 

[Triple Jim]

Ray has it right... of the three on the bottom of the regulator, the two non-red wires are AC in from the alternator and are interchangeable, and red is DC out to the battery. The other two wires just go to and from the fuse.

 

[Floydla1]

Hello Gentlemen,

First, thanks to Mullaney for redirecting my post to the generator section.
Second, thank you all for the prompt responses.
Once Light in the Dark showed me the picture, I found this regulator section buried in Figure 1-1.1 schematic in -34. The schematic shows with wires 1 and 2 connections not being critical -- just connecting across the resistor part of the regulator.

For now I am assuming that the stator part of the alternator G2 is good. If not, Erik's Military and Industrial Surplus (identified in a 10yr old post) still has it in stock for a reasonable amount. Based on ya'lls experience, is prudent to keep a regulator and alternator stator in parts inventory?

Thanks again,
Larry

 

[Light in the Dark]

Yes its not a bad idea to have both the DC and AC voltage regulators in your parts stock. These machines aren't getting any younger (and part availability isnt getting better). One of the users a few posts up, Triple Jim, makes a better than OEM quality AC VR for this machine. I would source his over whats in there originally.

 

[Floydla1]

I have two, spare voltage regulator boards, P/N 72-5020. Back in 2018 Marty Pontiff sold me one of his A/C rotors, but I have not followed up with a stator. I will go ahead and spare the battery charging circuit. Somebody said that finding the capacitor may be a problem.

Living on the gulf coast, I am getting ready for storm season and will replace my service breaker box with one that has a 50A transfer switch. There have been several posts crowing about the 003A' exceeding the 10kW design, but I am not inclined to push the unit. Do you concur?

Thank you much.

 

[Light in the Dark]

An 003 will easily produce more than 10KW if asked.

 

[Floydla1]

Nice!!

 

[glcaines]

My MEP003A is hooked up to the house through a manual 400 amp transfer switch and covers all circuits. I don't pay any attention to the load. It handles everything without difficulty, including geothermal heat pump, ovens, dryers, etc. The engine lugs down occasionally, but the genset has no trouble handling anything asked of it. It is used for backup quite frequently over the 13 years I've had it. I particularly like it due to the fact that it is air cooled and I don't have to worry about coolant and leaks, etc. Extremely dependable.

 

[Light in the Dark]

Nice!!

It should do 12.5kw very easily, and hold surges up to 15kw from my experience. I know folks who have pushed them harder, but only for short duration.

 

[Ray70]

Back to the OP's spare parts. One thing I would suggest on your spare AC VR's, if they are used and you have not personally seen then functioning, I would swap them into your machine and give them a good test.
There are 3 transistors on them that will quickly fail if the donor machine had any kind of starting / running problem that led to slow starts getting up to operating speed. I just worked on a machine a couple weeks ago with an injector and IP problem. Unfortunately it also developed an intermittent VR issue at startup due to him trying to run it with the starting problem. I had to throw in one of my spare VR's.
Currently have 3 on the shelf that need transistors replaced and testing.

 

[Floydla1]

Hello Gentlemen,

Good information all.

• Ray70 -- I have tested one of the two spare VR's. Your advise to test all is prudent. Since I exercise the unit weekly, I will include the tests.
• Light-in-the-Dark and glcaines. I am replacing the existing 200A breaker box with a 200A box with a manual transfer switch (12.5kW limit). The next box up is a 200A with a 100A switch. As much as I would like have a whole-house genset, I am not hard-wiring -- I am using plugs. The added cost of the 100A transfer switch and 100A plug / receptical exceeds my budget by quite a bit. But, it is good to hear the 003A can take a lickin and keep on tickin.

Thank you all.

 

[Floydla1]

Hello Gentlemen. I apologize for the tardy report on the replacement of the voltage regulator for battery charging. Easy job (after getting wiring clarifications). Fired the 003 up and confirmed that the batteries are being charged. Replacement regulator was found on e-bay using keyword 305-0512. Price of $95. Appears to be U.S. made. Again, thank you for your help.