re-wiring my MEP-004a for different voltages, including single phase

[bimota]

Ok, we (SanghaEnergy.org) did the side by side load test runs (MEP-004 converted to 240 and a 3 phase unit) and shot some video. Unfortunately limitations of the load test equipment left the results some inconclusive.

For converted MEP-004 (240 single phase) - we were able to get it to run and maintain almost 90 amps per phase - resulting in 21,600 volt-amps or 21.6kvr - we are using kvr rather than kw to keep the math simple. Limits on the load tester stopped us from pushing it harder, though we were surprised that the circuit breaker did not trip. Does anyone know the standard setting on the circuit breaker?

The three phase unit was loaded to 23,760 volt-amps or 23.7kvr - the next step (big step) up on my three phase load tester bogged the engine down. So I was unable to fully load test the unit on three phase output.

We are super busy but do hope to parallel load testers (I have one that will do 1kw increments) but I have to put it in parallel with the larger tester and not ruin anything so that takes time and as we know this blog does not really pay for anyone's time.

Needless to say I have two very strong MEP-004s ready to be put to work and I'd like to sell them ASAP. They are simply to powerful for most backup home applications, better suited to small machine shop operations.

 

[sewerzuk]

Ok, we (SanghaEnergy.org) did the side by side load test runs (MEP-004 converted to 240 and a 3 phase unit) and shot some video. Unfortunately limitations of the load test equipment left the results some inconclusive.

For converted MEP-004 (240 single phase) - we were able to get it to run and maintain almost 90 amps per phase - resulting in 21,600 volt-amps or 21.6kvr - we are using kvr rather than kw to keep the math simple. Limits on the load tester stopped us from pushing it harder, though we were surprised that the circuit breaker did not trip. Does anyone know the standard setting on the circuit breaker?

The three phase unit was loaded to 23,760 volt-amps or 23.7kvr - the next step (big step) up on my three phase load tester bogged the engine down. So I was unable to fully load test the unit on three phase output.

We are super busy but do hope to parallel load testers (I have one that will do 1kw increments) but I have to put it in parallel with the larger tester and not ruin anything so that takes time and as we know this blog does not really pay for anyone's time.

Needless to say I have two very strong MEP-004s ready to be put to work and I'd like to sell them ASAP. They are simply to powerful for most backup home applications, better suited to small machine shop operations.

Looks like you have some healthy engines on those 004's...both the single phase and 3 phase tests you ran showed some nice power numbers.

With regards to the breaker; it is actually just a contactor and not a conventional thermal circuit breaker. It is designed to trip at 130% of rated load at 8 minutes. It has an inverse time delay characteristic...so the more the setpoint is exceeded, the sooner it will trip. It uses the output from the large CT to effect that trip. So, depending on how long you ran it at that high load, it may not have made it to the trip setpoint. However, I have found the actual trip setpoint to vary a LOT. Some sets would trip at 120%, some would never trip even once the engine bogged down. I gave up on trying to correct this and simply tested the short circuit protection.
Did you add the resistors across the CT secondaries? If so, what size did you use?

 

[Madderoftime]

I am working on a mep004aas and I was getting voltage but the freq. meter would not display anything before. I was advised that this is due to not having a load on the unit. I did the conversion as you describe here and now I only get voltage if I hold the start switch up. As soon as I release it it drops to 0. The freq. jumps for a moment when I hit the start switch again and then when I let it go. I am stumped and need to actually see a wire diagram and or schematic that is large enough to actually read to trace the wires down. I'm back against a wall as I put my money out for this and need it working to run a welder in 5 days. Any help would be greatly appreciated!

 

[Madderoftime]

Reversed everything and on 3 phase it works ok. So something for that is not the same on my set. Still would need a schematic to track that down. I have a problem with getting the RPMs up there most likely a fuel issue.I'll start another thread on that.

 

[m-35tom]

so why do you not have a schematic? they are free. http://igor.chudov.com/manuals/Military-Generators/MEP-004A/

 

[Madderoftime]

so why do you not have a schematic? they are free. http://igor.chudov.com/manuals/Military-Generators/MEP-004A/

TYVM for the link! Mine the schematic was tiny!

 

[smurph]

Unfortunately, some of these things were wired up where it works, but it may not be wired to the schematic. Especially if it had been "worked on" before. Some of the sensor wires will work in the 3 phase config no matter what leg they are attached to. Take the accessory outlet, for instance. One leg would be tied to one of the 3 phase legs (would not matter which) and the other would be wired to neutral. Now, when you change to the single phase config one of the old 3 phase legs will float. If the accessory outlet was tide to it, then it will cease to function. The solution is to move the hot wire to a leg that is producing 120v.

So the only way to really correct this is to verify that the voltage selection board is wired to the schematic first. Then make the wiring adjustments as per sewerzuk's instructions.

Good luck! Just work through it and you will get it.

Steve

 

[captain]

madderoftime. I had an issue like yours regarding voltage. see my post #278. that solved my voltage problem where it went to 0 after releasing the start switch.

 

[Madderoftime]

madderoftime. I had an issue like yours regarding voltage. see my post #278. that solved my voltage problem where it went to 0 after releasing the start switch.

That was exactly it!!
Now it is single phase and freq is spot on. still low on the voltage side. Like 205 and 102 volts. I tested my 7.5 hp single phase air compressor and it pegs the % over 135% then drops right down to 25% and runs fine. Then tested my welder and it never gets over 25% with my welder. Would be better to have the volts a bit higher.

 

[rapidins]

After converting to single phase has anybody tried to parallel two MEP004 generators? Will it work the same as long as both generators are converted to single phase? Thanks

 

[212sparky]

After converting to single phase has anybody tried to parallel two MEP004 generators? Will it work the same as long as both generators are converted to single phase? Thanks<br/>

In theory you could, you would have to make sure your in phase and probably use syncing lamps to do it. It would be interesting to see if someone does it.

 

[smurph]

You could possibly use the sync lamps that are on the units already. However, the sync lamps are wired to L1 and L2. So I think you would need to move X15F from T2 of the voltage reconnect board to T3 on both units and X22S from B2 to C2 on the load contactor on both units. Because L2 is now floating with the single phase conversion. Then follow the TMs for the paralleling operation.

Please check my thoughts against the wiring diagram. I get cross eyed reading them.

I would worry about the wisdom of paralleling two utility sets for load sharing. If one of the throttles slipped enough to cause it to slip the electromagnetic lock, then bad things are going to happen. I guess you could do it in a pinch, but someone may need to monitor the sets closely. As one genset drops power and tries to drop RPM, it starts taking power from the other to try and maintain the sync. (the struggling unit's gen head will actually start running like a motor!) You should be able to see this by watching the load meters. The loads on each set should be equal at all times. If there is a problem, the load on the stable genset will go up and the load on the struggling genset will go down. The precise sets handle this automatically with the paralleling cables.

However, the ability to sync one genset to another so that the primary genset can be taken off line for service is a pretty cool feature.

 

[hamrepairguy]

Can someone please tell me if this same single phase conversion will work on a mep 006a thank you

 

[smurph]

In theory, yes. MEP-006 has a 12 wire gen head. But you might not be able to take schematic wire numbers from the MEP-004/5 conversion and expect them to be the same on the MEP-006. They may be, or not. But the functions/principles should be the same. The best course of action would be to compare the wiring diagrams and between MEP-004/5 and MEP-006. Figure out and understand what the MEP-004/5 modifications do and make those same modifications on the MEP-006.

 

[sewerzuk]

Can someone please tell me if this same single phase conversion will work on a mep 006a thank you

The conversion is similar but not exactly the same. With the -006a you can just do the 12 lead re-wire without moving control wires, but there are a few funny meter readings if you do it that way.
I have converted a couple of -006's but didn't write down the wire movements.
I plan to make another video the next time an -006a finds its way into my shop.

 

[hamrepairguy]

The conversion is similar but not exactly the same. With the -006a you can just do the 12 lead re-wire without moving control wires, but there are a few funny meter readings if you do it that way.
I have converted a couple of -006's but didn't write down the wire movements.
I plan to make another video the next time an -006a finds its way into my shop.

Thank you both for taking the time to respond. I will hold off on doing the conversion until you publish the control wire reconfiguration. I am doing the conversion for a friend and do not want to risk damaging his genset.

Thanks again

 

[bimota]

Converting any of these -004, 005 or 006 is like taking a Semi-truck with an 80,000lb towing capacity and using it as a 1/2 ton pickup truck. An 006 at load is running 7 gallons per hours - you really want to pay $50 an hour to power your house?

 

[hamrepairguy]

Converting any of these -004, 005 or 006 is like taking a Semi-truck with an 80,000lb towing capacity and using it as a 1/2 ton pickup truck. An 006 at load is running 7 gallons per hours - you really want to pay $50 an hour to power your house?

Thats up to my friend,but he does need every bit of power that it will produce on single phase.

 

[Another Ahab]

Converting any of these -004, 005 or 006 is like taking a Semi-truck with an 80,000lb towing capacity and using it as a 1/2 ton pickup truck. An 006 at load is running 7 gallons per hours - you really want to pay $50 an hour to power your house?

The math appears a little fuzzy:

- Gasoline currently at $3/ gallon (+/-), right?

 

[smurph]

Converting any of these -004, 005 or 006 is like taking a Semi-truck with an 80,000lb towing capacity and using it as a 1/2 ton pickup truck. An 006 at load is running 7 gallons per hours - you really want to pay $50 an hour to power your house?

Who said anything about powering a house? Why make assumptions? Some may have a real need. Others may do the conversion because they want to. Which is wrong?

With that said, I think I will go for a drive in my M934 hauling exactly nothing getting 7 MPG.