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

Hammer · Dec 8, 2011

That is great news!

storeman · Dec 8, 2011

WOW! A break through! The price of 004a's is going UP.

sewerzuk · Dec 9, 2011

storeman said:
WOW! A break through! The price of 004a's is going UP.

Sure does make them more useful for the person looking for a backup gen for their home!

I got the chance to put about 58A (14kW) on the set for about an hour tonight; no issues at all. In fact, voltage varied by less than 1 volt from no load to 58A, which is actually better than it does in its factory 3 phase config. Looks like the VR mods did the trick.

Still need to pull one turn from the CT and check the ammeter and overload trips. If it looks like things are going to work, I'll put the set through my normal overload tests and make sure nothing burns up in the process

The conversion (so far) might look a little complicated, but it is still 100% on the reconnection board and just involves a few wire swaps. I think I could do the conversion in about 15 minutes (without the CT mod I am planning) on future sets. If everything works as expected, I'll make a full set of instructions and an additional video.

R Racing · Dec 9, 2011

Thank you for your hard work !! :beer:

UnReconstructed · Dec 9, 2011

WOW......that is absolutely fantastic news! I had been planning on pulling my Voltage reg/exciter this weekend and doing some bench work on it....I did a little research, and found that the IC I was looking at is probably the Mil equivalent to a LM723; a pretty common voltage regulator...

It kinda looks like it is hooked up in a switching configuration.......

But YOU....Mr SewerZuk....you have made it unnecessary for me to do this.....

You have probably saved me several hundred dollars. I was going to hook my genset up to my house with two legs feeding a couple of step up transformers to give my 240 volt circuits what they need, and feed the rest with the remaining 208 leg.

But NOW all i have to do is wire it up.....

Thank you.....I know I'm only a private in this army, but I nominate SewerZuk for 5 star general.....

decodeme2 · Dec 9, 2011

U Da MAN!..wow..been following this post for days...i cant wait to try this on my 20kw 4 cly gen. I took my mep-005 30kw off the house and installed the 20kw i got from GL. The 30kw at full load from my house did 30% on the load meter max. heat pump, compressor, EXelary heat etc. also pu tthe stove and dryer on. I did this with the 20kw and it was at 80% load.
I feel your rewiring will help drop the load off the single phase of the 3 phase gen.
Also could you tell me how to attach the wires from my house to the L1 2 3 4 lugs on the gen?.
Will I have to change them to take advantage of the single phase now? Since im using 1 phase of the 3 phase gen..
Thanks again sewerzuk..!!
Kevin

sewerzuk · Dec 9, 2011

decodeme2 said:
Also could you tell me how to attach the wires from my house to the L1 2 3 4 lugs on the gen?.
Will I have to change them to take advantage of the single phase now? Since im using 1 phase of the 3 phase gen..
Thanks again sewerzuk..!!
Kevin

If you do the modification as I have described, your 2 "hot" legs are L1 and L3, and the neutral is L0.

As the gen sits right now (without the CT mod I am planning), it could be used in single phase with no problem. The way the overloads work in these sets is different than a common thermal circuit breaker. They won't trip until the overload setpoint has been exceeded for about 8 minutes; so as long as your steady state load is below about 55 amps, you're all set. Temporary loads (even for several minutes) that drive it up above 55A won't cause a trip.

skidunits4you · Dec 9, 2011

You put 58 amps on mep004 and no problem. This is great news. so the conversion did not really derate the unit. so doing the same to afew of my mep005s should not derate them? Great work on your part. THANK YOU

sewerzuk · Dec 10, 2011

skidunits4you said:
You put 58 amps on mep004 and no problem. This is great news. so the conversion did not really derate the unit. so doing the same to afew of my mep005s should not derate them? Great work on your part. THANK YOU

The conversion for the -005 should be exactly the same as the -004; the schematics I used for the -004 cover both models.

This de-rating thing can be a complicated question. We have a few things to worry about:
1. The current through individual generator windings. I have not yet taken current readings and compared them at full load 3 phase vs single phase on each winding. I do intend to do this. I don't think this is an issue, as the zigzag configuration is considered "balanced" (although it looks a little strange on paper).
Edit: I have tested all 12 leads under full load, and the current was balanced to less than 1A between all leads
2. The cable size from the reconnection board to the breaker, the breaker itself, and the cable going to the load terminals. The breaker is not an issue. It can handle the extra current. The cable size is too small for the higher single phase current through L1 and L3. It should be up-sized. If you don't upsize it, I seriously doubt anything bad will happen...but you may experience a slight voltage drop across those lines at full load and/or some warming. I intend to put some 4 AWG cable on my -004.
3. The overload trip setpoint on the generator. I have not yet tried to raise the trip setpoints for the overloads (planned for this Sunday night). They still trip at their 3 phase setpoints. This is roughly 55A for the -004 (mine trip at about 60A), and 110A for the -005. At the new higher voltage, this gets you 14kW for the -004, and 27kW for the -005. This means that, at the new higher 120/240 voltage, the sets trip at just below their full rating. However...the set won't trip for a full 8 minutes of overload. That means that, on your -005, you can pull 27kW all day long and for a few minutes at a time put even more (40kW is possible on a good-running -005, 23kW on on -004).

The bottom line is, you can do the single phase mode I show in my video, move the leads on the reconnection board as I describe in post # 40, and put your generator to work single phase. It will work just fine this way, especially if you intend to load it to 50-80% of its capacity with only occasional 100% transients.

I'll have another video up 2 weeks from now describing/detailing the ENTIRE conversion, not just the zigzag mod shown in the first video. Should be fairly easy for the average wrench-turner to accomplish.
Edit: New video is at the end of post #1

n1oty · Dec 10, 2011

It's time to get a shipping quote for shipping one of these generators from either Letterkenny or Meade since they seem to be in abundance at these locations. I'm afraid that shipping may turn out to be prohibitive however. This may be an interesting acquisition if the shipping is manageable.

John

skidunits4you · Dec 10, 2011

Keep your eyes open I hear a few will be coming out in New England soon.I have been told some stuff will be coming out at Devens. Guess we wait and see

decodeme2 · Dec 10, 2011

So, I need to follow the directions in post # 40 below, not as in the video?..

"I cut the buss bar that connected T10, T11, and T12 together and ran the jumper from T12 to T3, I created a floating neutral inside of all of those components. This explains the strange readings I was getting on the voltmeter, and was likely the biggest reason for the large voltage droop. I moved the lead (X12EG16N) from its original position on T12 to T13, restoring the neutral."

Or, do i do both?..?..(X12EG16N) is the jumper lead? Or the factory labeled cable?
Sorry about all the jestions, maybe someone else had the same question./..

...thanks again for your time with this..
Kevin..

OPCOM · Dec 10, 2011

Thanks for posting this and using a descriptive title and for explaining why it works. Although the info's been generically posted in one form or another as an answer to various questions, its much easier to find it as a topic. That is important!

sewerzuk · Dec 11, 2011

decodeme2 said:
So, I need to follow the directions in post # 40 below, not as in the video?..

"I cut the buss bar that connected T10, T11, and T12 together and ran the jumper from T12 to T3, I created a floating neutral inside of all of those components. This explains the strange readings I was getting on the voltmeter, and was likely the biggest reason for the large voltage droop. I moved the lead (X12EG16N) from its original position on T12 to T13, restoring the neutral."

Or, do i do both?..?..(X12EG16N) is the jumper lead? Or the factory labeled cable?
Sorry about all the jestions, maybe someone else had the same question./..

...thanks again for your time with this..
Kevin..

You need to do both; the buss bar cut/jumper mod in the video wire the 12 leads from the generator in zigzag configuration.
The lead swaps in post 40 re-wire the voltage regulator/exciter, thermal watt converter, and many of the control box components to work properly with the zigzag mod.
If you can wait for a couple of weeks, I'll be posting a complete video showing the entire changeover (zigzag mod, VR/TWC/component re-wire), with the optional CT re-wire (which I haven't tried yet).
Edit: video uploaded to youtube. You can find a link to it at the end of post #1

livemonarch · Dec 11, 2011

Hats off for the best thread I have ever seen!
I have a specific use for the generator...to start a 17 hp 3 phase hydraulic motor.
It is wired for 575 volts, each leg pulls 51 amps for 3 seconds as motor starts and drops to 24 amps per leg thereafter. Motor was hoked up using 600v 8awg copper...all ok for past 25 years.
Will purchase correct step up transformer or rewind motor if necessary.
Motor is 575/3/60 star delta

Will the mep-005 with proper transformer start our motor and safely run it?
Any tips for starting large motors on generators?
Anybody have experience with soft start motor controllers?

Thank you for the assist!
The depth vids are excelllent!!! :beer:

PeterD · Dec 11, 2011

livemonarch said:
Hats off for the best thread I have ever seen!
I have a specific use for the generator...to start a 17 hp 3 phase hydraulic motor.
It is wired for 575 volts, each leg pulls 51 amps for 3 seconds as motor starts and drops to 24 amps per leg thereafter.

Will the mep-005 start our motor and safely run it?

Thank you for the assist!
Your in depth vids are excelllent!!!

That 575 volt requirement is a problem since the MEP-005A maximum voltage is 416 volts. You may need to rig a transformer.

sewerzuk · Dec 11, 2011

livemonarch said:
Hats off for the best thread I have ever seen!
I have a specific use for the generator...to start a 17 hp 3 phase hydraulic motor.
It is wired for 575 volts, each leg pulls 51 amps for 3 seconds as motor starts and drops to 24 amps per leg thereafter. Motor was hoked up using 600v 8awg copper...all ok for past 25 years.
Will purchase correct step up transformer or rewind motor if necessary.
Motor is 575/3/60 star delta

Will the mep-005 with proper transformer start our motor and safely run it?
Any tips for starting large motors on generators?
Anybody have experience with soft start motor controllers?

Thank you for the assist!
The depth vids are excelllent!!!

Probably best to start a new topic on this as it isn't really related to the single phase mod...

timass1 · Dec 11, 2011

Thanks for the helpful info and video. I look forward to your next one. I've been wondering if this was possible. Great thread and right to the point. Many thanks. Those of you who live up here in N.E send me a PM, would like to get together sometime and talk.

mooses3 · Dec 16, 2011

MEP-004A Generator Static Exciter Problems/NEED HELP

I pulled out the voltage regulator / static exciter control because I had know AC output. The T2 transformer is shorted and burnt into on the primary side of the winding. I was wondering what caused the problem and where can I find a replacement transformer or a static exciter unit.

Terry

decodeme2 · Dec 19, 2011

Thanks
sewerzuk
for all the info! Will wait until the new Video is made!....
Kevin..

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

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