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

[smurph]

I think sewerzuk came out with an update on the wiring that was not in the original video. I believe that is where that came from, anyway. However, it does work. It worked with the original wiring scheme too, but I think the output was a bit less and sewerzuk found the better solution.

How that circuit works is the field is flashed from the batteries during the time you are holding the switch in the start position. When power is generated, and you let off the switch, the voltage regulator/exciter gets a voltage from one of those wires. It is possible that it is the same circuit as the convenience outlet. But that voltage is then what the regulator/exciter is using to keep the filed coils energized. So it sounds like to me that one wire is causing your symptoms. I'll dig out the TM and see if I can narrow that down a bit. At one time, I had all of this in my brain. I had to diagnose and repair a voltage regulator and I got all too familiar with the thing. But I didn't retain it!

Also, the wires get a little tight under the reconnection board. It is possible that one simply got broken with the insulation still in tact. Or it could be a switch problem.

 

[captain]

Thank you for the help. It could be anything although I was very careful to reroute any wires that were tight and I tried not to kink any while moving them around. I will also attempt to find out what X8HH16B does and see if moving that from t11 to t7 will help any. Thank you for the info on how it works.

 

[1800 Diesel]

Hi Matt,

I've just completed my third single phase conversion on an MEP-004A and wanted to ask about the voltage differences on the two legs. As with the prior two sets I did, L1 & L3 voltages are not both the same. In today's test for example, L1 was showing 113 volts & L3 was showing 126 volts. I know that's acceptable for supplying voltage for 120v service but I'm still curious as to why this continues to happen. I can adjust voltage output so that one leg is 120v but then the other leg will be either too low or too high. What I did today was just test across L1 & L3 & adjust voltage output until I saw 240v.

To provide a few more data points, I had 60 amps on L1 & 54 amps on L3, with load meter showing near 120%. The % load value seems lower than the amp readings either. BTW, the three resistors were also installed.

Also since much time has passed since the last two conversions I completed, I was wondering if you had seen any questions about unequal output voltages following the conversion. If so, have you recommended any new wiring changes that are different from the ones I used from your original video? Thanks for any advice you could offer.

Kevin

 

[captain]

I think I found the issue I was having with not generating power unless you hold the start switch in the start position. As part of the single phase conversion for use with my house I unbonded ground from the back of the neutral lug. When attach ground and neutral again it works fine. Is this normal? It seems to me like something that should be run to neutral has been run to ground instead since in standard configuration they are electrically the same. However when it is set up for use with my house they are only electrically the same when plugged into the house and not when attached to my load bank for a run.

 

[captain]

Sorry guys for wasting your time. In 3 phase with N+G works fine. With N unbonded from G does not work. In single phase it does not work in either configuration. I'm just going to haul it to the scrap yard this week. A mod can feel free to remove my posts since they do not help anyone to solve any issues.

 

[rustystud]

Sorry guys for wasting your time. In 3 phase with N+G works fine. With N unbonded from G does not work. In single phase it does not work in either configuration. I'm just going to haul it to the scrap yard this week. A mod can feel free to remove my posts since they do not help anyone to solve any issues.

I wouldn't give up that easy. I'm not familiar with the MEP-004A , but I know plenty of guys here are . So hang in there and maybe someone will have some good advice for you.

 

[panzerwillie]

Great info planning to switch my MEP005A to 120/240 thank for all the posts

 

[1800 Diesel]

I just reconfigured my 004a over to single phase. I just had one question regarding the ground that I did not see elsewhere. I removed the ground from L0. It looks to be X13BN. The ground stud has 2 other smaller gauge wires. One that runs up to the right near the reconnection board and another that goes off to the left. Is everything done right or do I need to move either of those 2 wires? Is there any reason not to run the jumper wire from T12 to T2 on the bottom of the board? On the top the stud is only long enough to get 3/4 of the nut on. Thanks again for all the help. The reconfiguration was very fast and easy.

Captain,

For all the wiring changes (jumper & instrumentation wire moves) I've been doing on the underside of the board. The generator used in original video from Zewerzuk has the bus bar on the upper side of the board. Also, on all 3 units that I converted, the bus bar was on the underside of the board.

I haven't read through your other posts but will take a look at them when I get a chance.

Kevin

 

[1800 Diesel]

I think I found the issue I was having with not generating power unless you hold the start switch in the start position. As part of the single phase conversion for use with my house I unbonded ground from the back of the neutral lug. When attach ground and neutral again it works fine. Is this normal? It seems to me like something that should be run to neutral has been run to ground instead since in standard configuration they are electrically the same. However when it is set up for use with my house they are only electrically the same when plugged into the house and not when attached to my load bank for a run.

Captain,

Just trying to learn something here, but I wanted to ask why you "unbonded ground from the back of the neutral lug"? Is this something you did on the generator itself or something in your house panel? Hopefully some time this year, we'll be connecting our MEP4 to our house so I need to understand what you were doing.

Thanks

 

[1800 Diesel]

Sorry guys for wasting your time. In 3 phase with N+G works fine. With N unbonded from G does not work. In single phase it does not work in either configuration. I'm just going to haul it to the scrap yard this week. A mod can feel free to remove my posts since they do not help anyone to solve any issues.

Captain,

It might help if you could do a few sketches with each wiring connection shown with some descriptive text for each one. Maybe some photos would help as well. Also, since this unit is obviously in a running condition (with all other mechanical & electrical functioning), I definitely wouldn't consider scrapping.

Kevin

 

[captain]

Not to be long winded here but my problem is I have been working on this for months. I'm also facing a lay off in 2 months. If that happens I have to sell most of what I own in about a week in order to get the house up for sale. A single phase generator is hard enough to sell that fast. A 3 phase I think would be impossible.

As far as unbonding ground an neutral. It is my understand that it is required in order to hook the generator up to the house since the house its self has neutral and ground bonded in the main breaker panel. If I recall there are a number of posts that go in to more depth about why. They are also written by people who know much more about that type of thing then I do.

As far as my generator goes. Everything works in 3 phase. If I remove ground from neutral in 3 phase it only produces power if you hold the start switch up. In single phase no matter how ground and neutral are wired it will only produce power with the start switch held up. My buss bar was also located in the bottom. I removed it and cut it. I also moved the 3 leads under the board and made the correct jumper and termination on the top of the board. Those few movements I have checked a number of times and they are correct per the video. From hours of googling it seems like no one has had this problem before. If I can fix it and the worst happens I'll take it with me where ever I go. But if I can not then it has to go.

 

[PeterD]

... If that happens I have to sell most of what I own in about a week in order to get the house up for sale. A single phase generator is hard enough to sell that fast. A 3 phase I think would be impossible.

As far as unbonding ground an neutral. It is my understand that it is required in order to hook the generator up to the house since the house its self has neutral and ground bonded in the main breaker panel. ...

First, I hope things work out and you don't get laid off.

Second, don't worry about bonded neutral. That's the buyer's issue. The question as to bonding or not is not an absolute. Done properly either configuration can be used, and be safe.

Third, (sorry, this is going from memory and it's dark outside right now) my MEP-004 the bonding is a single wire that attaches to a screw attached to the framework near the connection panel. Only this one wire is removed, and the wire is obvious. If you want I can take a picture, perhaps tomorrow if I have the time. Just recognize that the buyer may well want neutral bonded. Let him decide.

 

[captain]

Thank you for the info. The bonding part I am ok with. My problem is when converting to single phase as in the video that the generator will not produce power unless the start switch is held in the up position. As soon as you let go voltage drops off. This happens regardless of bonding. Now to make things even more odd in 3 phase the generator works but only with neutral bonded to ground. If I remove the ground wire from the neutral lug then it behaves as it does in single phase. The only thing I can guess at is someone moved a wire or two before I got the set. Something that is electrically the same in 3 phase but not when I changed over to single phase. Either that or I am incompetent and cant seem to handle moving 3 wires and cutting a bus bar. Both might be true!

 

[1800 Diesel]

Thank you for the info. The bonding part I am ok with. My problem is when converting to single phase as in the video that the generator will not produce power unless the start switch is held in the up position. As soon as you let go voltage drops off. This happens regardless of bonding. Now to make things even more odd in 3 phase the generator works but only with neutral bonded to ground. If I remove the ground wire from the neutral lug then it behaves as it does in single phase. The only thing I can guess at is someone moved a wire or two before I got the set. Something that is electrically the same in 3 phase but not when I changed over to single phase. Either that or I am incompetent and cant seem to handle moving 3 wires and cutting a bus bar. Both might be true!

Captain,

IIRC, a defective speed switch could be causing the field not to be flashed. This could be one of those coincidence failures (or murphy's law in action).

I have an ASK model I'm building for my brother & it is doing the same thing as yours. I found a missing pin on the wiring harness to the speed switch. At this time I haven't repaired the connector due to other time priorities, but I believe that is the problem on this unit.

The other forum has several related threads; this is one of them:

http://www.smokstak.com/forum/showthread.php?t=117190

Hang in there with the generator & job future!

Kevin

 

[captain]

I did not look at the pins on the speed switch yet but I did consider the switch. I made sure it was not in need of a reset too. What I find odd is in the 3 phase configuration it has never once failed to make power in the 2 or 3 years I have owned it. Even when I set it back to 3 phase from single it produced power fine the half a dozen or dozen times I fired it up.

 

[bimota]

Couple thoughts and a request for parts:

1. I need an MEP-004 voltage regulator here in CA. Please email if you are parting to have parts machines.
2. I need a speed switch for an MEP-006 - anyone know if the speed switch on the MEP-004, 005 and 006 are the same?

I'll be converting my MEP-004 back to three phase for several reasons which we should debate here or start a new blog:
1. The MEP-004 is capable of very long runs at very good, like 60 amps per phase, output. Converting to single phase in a sense wastes 1/3 of the power output. I'd argue that it is less expensive and more appropriate to buy a 5-15kw transformer and install that to convert some of the energy to single phase. Then you still have all the potential for powering your home, your shop and the neighbors house etc.
2. MEP-004 have been rising in value and single phase 10kw generators while a little difficult to find are way, way less expensive to find and install for backup. I cringe when I hear someone putting in an MEP-004 converted to single phase as a house backup. The rats will eat the generator before you could wear it out even with power outages all the time.
3. Parts for MEP-004 are very, very expensive new. So let's say you do the install at your house and then in mid winter you need a major part replacement - you are totally screwed because a rapid replacement part will cost you three times what the generator cost and it will be hard to get.

Best to put the machine to use for what they were designed for that modify them. These are great generators for small remote machine shop or wood shop operations where one runs a generator to power three phase power tools 4-6 hrs per day. As a home backup they are not appropriate.

 

[rustystud]

Couple thoughts and a request for parts:

1. I need an MEP-004 voltage regulator here in CA. Please email if you are parting to have parts machines.
2. I need a speed switch for an MEP-006 - anyone know if the speed switch on the MEP-004, 005 and 006 are the same?

I'll be converting my MEP-004 back to three phase for several reasons which we should debate here or start a new blog:
1. The MEP-004 is capable of very long runs at very good, like 60 amps per phase, output. Converting to single phase in a sense wastes 1/3 of the power output. I'd argue that it is less expensive and more appropriate to buy a 5-15kw transformer and install that to convert some of the energy to single phase. Then you still have all the potential for powering your home, your shop and the neighbors house etc.
2. MEP-004 have been rising in value and single phase 10kw generators while a little difficult to find are way, way less expensive to find and install for backup. I cringe when I hear someone putting in an MEP-004 converted to single phase as a house backup. The rats will eat the generator before you could wear it out even with power outages all the time.
3. Parts for MEP-004 are very, very expensive new. So let's say you do the install at your house and then in mid winter you need a major part replacement - you are totally screwed because a rapid replacement part will cost you three times what the generator cost and it will be hard to get.

Best to put the machine to use for what they were designed for that modify them. These are great generators for small remote machine shop or wood shop operations where one runs a generator to power three phase power tools 4-6 hrs per day. As a home backup they are not appropriate.

I was originally going to buy a MEP-004 , but a MEP-003A came up for auction first so I bought that thinking I would resell it later. Now after buying my MEP -003A I realized even that was over-kill for my home. Now I'm just running the MEP-002A. If I was going to run a shop with all the 3phase equipment I would get the MEP-004 but for just a home a MEP-003A or MEP-002A is a way better way to go, just for fuel usage alone . You will always run into problems trying to modify something into what it was never intended for. I say just save yourself the grief and buy the right size generator for your needs .

 

[1800 Diesel]

Thank you for the info. The bonding part I am ok with. My problem is when converting to single phase as in the video that the generator will not produce power unless the start switch is held in the up position. As soon as you let go voltage drops off. This happens regardless of bonding. Now to make things even more odd in 3 phase the generator works but only with neutral bonded to ground. If I remove the ground wire from the neutral lug then it behaves as it does in single phase. The only thing I can guess at is someone moved a wire or two before I got the set. Something that is electrically the same in 3 phase but not when I changed over to single phase. Either that or I am incompetent and cant seem to handle moving 3 wires and cutting a bus bar. Both might be true!

Captain,

I can't offer much help on this one as will soon be occupied for several months. If Sewerzuk could weigh in, he could probably help us out. I'm thinking he's busy somewhere as well--seems he too has been a little "scarce" for quite awhile.

Good luck with everything.

Kevin

 

[captain]

Now that I have a lot of free time on my hands I was able to look at my gen and read some posts. Thanks indirectly to sewerzuk for fixing part of my issue. I now make voltage in single phase. The following quote is from him from another post in another thread. "My lead movements changed the voltage being supplied to a control transformer inside of A11 from 240v to 120v. That control transformer supplies field current. It seems to work fine on the -004a, but maybe with the higher field current in the -005a it can't "keep up?" To correct this, you would need to move the X8HH16B lead from T8 to T7 (instead of from T8 to T11, as my conversion process currently shows)." Moving X8HH16B from T11 (originally T to T7 solved the issue of no power in with the single phase mod.

Now the only problem I have left is ground and neutral bonding. In my limited understanding of electric (magic) I need to unbond neutral from ground at the generator in order to hook up to the house. I did this by removing the ring terminal from the back of L0 that is attached to the wire/ground stud on the generator frame. When I do this the generator makes no power. If I attach ground back to neutral it runs well. Is this correct or is something else misswired?

Lastly is a question about the general nature of the beast. When I first fire it up the HZ peg the gauge before it calms down to 60. Does that seem about standard? I'm guessing its just an electronic thing as the engine is not over revving.

Thanks all.

 

[Munchies]

I prefer to unbond at the ground then wrap up the unused wire and safely zip tie it away. I cant imagine why what you described is happening. The only thing I can think of, is your breaking a ground connection to something that is needing it, so it was backfeeding. Disconnect it at the ground terminal to eliminate mixing up the wires. All those white wires look the same after awhile.