Voltage selector switch for 1031?

[dependable]

I was wondering if any of you generator experts could recommend a voltage selector switch to wire into my 1031 truck. It has a 12 kw, 12 lead alternator head. It is wired for 208v, 3 phase. Schematics show it can be reconfigured to other voltage/ phases. As many of the MEPs have switches that accomplish this, would it be possible to wire one into the truck to make it more versatile?

 

[brianrbull]

I too would be interested in this "Mod" how about the reconnection switch off a MEP-003?

 

[dependable]

Ok, let me re phrase the original question. If I were to have a qualified professional add a voltage, phase selector switch to a 1031 truck, would a switch for any similar or higher amp MEP 12 lead unit work and would it be wired similarly? I know the generator head can be wired to a 240v configuration that could power the house or shop (with a line safety transfer switch of course). Is this a feasible modification? Perhaps something that could be done with a salvage panel from parted out MEP 003 or larger? The air compressor motor in the truck and some welders are 3 phase, so I would like the 1 or 3 phase option. Thanks.

 

[PeterD]

I think you are looking for a change over board, more than a switch. Switches to do this, at the power you indicate you have, are expensive... A board, such as on a MEP-004 will allow you to change power options.

I do have one such board, that I stripped out of an old 'pre-MEP' generator set, which I'd be willing to part with (requires a fair donation to SS of a reasonable amount, plus shipping and handling...)

 

[dependable]

Would the the board or switch from MEP -003 or 004 or any similar 12 lead unit work? In that case it would be a modification others could try as well.

 

[dependable]

Ok, I have a board from a MEP 018 10 kw genset I bought on e-bay. My main question is; Should I just use switch and output lugs, or would it be good to incorperate elements of board for better quality power, gauges, ect. I want to hook to 120/240 house power and keep 3 ph capability for compressor and other tools. Put either can in photo for size of switch scale. I know others are interested in this mod, may be I should have posted this on CUCV forum, but am hoping to get input from the genset folks who might be familiar with this board. Just got the plug that will screw into back of board. Thanks.

 

[dependable]

Have not got around to this modification yet. The M1031 12 KW alternator has 12 wires. Will it configure to 12 wire Phase/Voltage selector switch if it is rated for the current?

Another way to put this question is; Are the positions and outputs the same for all 12 wire generators ? As in if I hook the #1 to #1, #2 to #2 ...ect, would the switch work? Assuming it is in good condition.

 

[NDT]

I cannot answer your immediate question, but I would not assume the wire numeric designations from the 1960's MEP are the same as the newer Marathon alternator. I would compare the schematic of the switch with the required connections from the SECM alternator, which are in the tech data sheets, and make sure the connections are correct. Let us know how this turns out. I was not crazy about the idea of powering my house from 2 of the 3 phases, although it can be done.

 

[dependable]

I have studied both the MEP-018a and the Marathon manuals. They both refer to the 12 leads as T-1 though T12. There is no diagram in the 018 manual I have that corresponds to the reconfiguration diagrams in the Marathon manual. I do also have an intact MEP-018, but it needs a bit of work to run, so I can look at it if I know what to look for, but not test it.

 

[NDT]

What I would do is remove the rotary switch from the control panel, and, using an ohmmeter/ continuity tester, write down which terminals connect and disconnect in all the switch positions, and then compare that to the connection diagram in the Marathon tech sheet.

 

[Isaac-1]

There are generally 2 systems for numbering the leads of 12 lead reconnectable generators the American T system and the European W system. I strongly suspect that a modern Marathon head would use the T system since they are currently owned by Cummins which also owns Onan.

Ike

p.s. any 12 lead output chart should show the pair numbers where you can check resistance to confirm the numbering, there are also test procedures you can go through comparing various resistances to number an unmarked generator head, just be aware certain leads are arbitrary depending on your starting point.

 

[dependable]

Have found some time to mess with this. I don't understand my results in testing reconnect switch. In 120/240 mode I am getting the following L2= T1 & T9. L3= T8 & T12. L0= T3 & T6. Am using continuity tester from T inputs to output lug. Even if numbering were off, I think I should have 4 leads connected for L0. I think this is true for zig zag or double delta configurations. I figure I must be missing something.

Does anyone know the 120/240 single phase configuration for MEP-018? One of the pictures shows data plate, don't know if accurate. (I think the 002a s are double delta)

The 12KW Marathon manual shows a zig zag 120/240 single phase configuration, but if this switch hooks it up as double delta, my understanding is that this is ok too.

 

[dependable]

It turns out the connector plug diagram in the MEP-018a TM is transposed from reality(see picture).

So in 120/240 single phase; L0= T 5,8. L2= 3,7. L3= 3,11. T 1+12, 4+7, 6+9 are paired together. Still wondering what schematic diagram the single phase hook up would correspond to. But now I found the manual's error, the 120/208 3 phase does correspond with 12 lead low Wye diagram in Lima manual.

 

[dependable]

Found out from someone on Smokestack forum that the 120/240 is off a 3 phase parallel delta, but taken off as 2 1 phase 120/neutral legs. The configuration is one of the ones in the Lima Mac manual, so I know it is good to go with 1031 12 kw alternator. Now I just need to figure out how I want to mount it in truck. Also wondering if anyone had any ideas on how to hook up a percent load meter.

All I am using from the MEP-018a control panel is the switch, output lugs and input plug. The main output wires still pass though the current detector coil, but all the gauges and other control panel guts seem to relate to the 018 voltage regulator.

 

[dependable]

I got the control box more or less finished. I made things difficult for myself, but learned a lot in the process. Decided to go with the MEP-018 panel gauges and controls, even though some digital instrumentation would have been easier and more practical.

If I were to do this again, I would just cut out and cap the wiring for the engine control and the voltage regulator. This would save a lot of time and enable me to keep the wire harness neater. I also cut the box down a little too small. The only control I lost was the voltage adjustment, as it goes though the voltage regulator.

I will probably wire the original 1031 panel into the box before the circuit breaker, as it has its own, and switch will usually be in the 120/208 position.

Actually started this project before I had a good MEP-002, so M-1031 won't be a primary source of standby power. I followed though for learning purposes anyway, and it has been a slow winter. Will post another picture when I get it installed.