MEP-004a

[GreenMachines]

Anyone have any experience wiring regular generator receptacles (twist lock etc). My thought was to run the generator set at 120/208; wire from two of the L1,L2,L3 lugs into a main circuit panel just as wired in a house. One 120 leg from the generator to each main lug in the circuit panel and L-0 as the neutral and ground to ground lug. Then I could use circuit breakers to make the twistlock 240v and 120v receptacles as individual circuits, just like generators sold in stores. A 240 circuit would get 120v from each leg in the circuit panel and single 120v breakers would get only 120v since it only grabs from one leg. Sounds like it should work???? Any suggestions?????

 

[Chevytruck]

do you got an isolator box?
its dangerous to hook a generator up to the grid without an isolator box

not here to rag on anyone

 

[GreenMachines]

isolator box

Thanks for the reply! I am not planning to connect to the power grid. Just trying to provide receptacles on an MEP-004a both 120v and 240v just like any readily available generator would have. Any suggestions??? I have been reading up on phase converters and Buckboost transformers I may have to use something like that?????

 

[Speddmon]

an MEP-004 doesn't provide 240 volts phase to phase (line to line) like house wiring or other generators do. Not without some modification anyway.

You idea sounds good but if you go line to line from any two lines (L1, L2, L3) when you're in 120/208 mode you'll get 208 volts and not 240.

 

[GreenMachines]

Thank you for the reply. You are quite right, 208 would be the result if I wire things as I had described. I have been doing some research and realized the result would be 208v line to line. I would have 120v line to neutral. I found out that the 208 would work for anything that requires 240 just less efficient because of the lower voltage. I also found what is called a buck boost transformer, it may be able to boost the 208 up to 240 to maximize efficiency. I am going to call the company tomorrow to get more information. Again THANKS for the reply and for good information!!!!! Always appreciated!!!!!!

 

[jeepin]

There is another site that has lots of info about the MEP gensets, try a search at Military MEP and Aircraft Gen-Sets - SmokStak

 

[Speddmon]

I found out that the 208 would work for anything that requires 240 just less efficient because of the lower voltage.

Be careful with that. Just because most motors will run on 208 volts doesn't mean that the entire system will like it without modification. My heat pump for example will run on 208 volts but for the controls of the heat pump to work, the control transformer inside needs to be rewired for the 208 volts...kind of a PITA to do at every power outage!

Also, I didn't know this until I started looking into generators very seriously. There is a condition known as wet stacking that occurs when you don't have enough load on a liquid cooled diesel engine.

 

[GreenMachines]

Speddmon once again thanks for the reply and good advice!!!! I wonder if the generator could be rewired at the 120/208-240/416 plate to put out 120/240?

 

[Speddmon]

I saw something on the internet one time about a partial reconnect, more of an open delta type of connection, some people call it a zigzag connection, but it looked like it would do the trick. I'll look around when I get some time and see what I can come up with.

Since it's a 12 lead gen head, I'm positive it can be rewired, but I do not know what it will do to the excitation and monitoring aspects of the set. If anybody else has any input for GreenMachines feel free to throw it out there.

 

[Amnon]

Since it's a 12 lead gen head, I'm positive it can be rewired, but I do not know what it will do to the excitation and monitoring aspects of the set.

Please let us all know if you do. Delk's surplus in NC buys a lot of them and I was told they rewire them for 120/240 before selling them for around $5500. I am going to give them a call and see if someone there could help. I got mine about a month ago. Oh yeah, anyone knows what the AAS stands for? (MEP004AAS) ??

Amnon

 

[Speddmon]

The AAS is the the acronym for the sound deadening enclosure. It should actually be just "AS", but people forget that the first A is actually in the model # of the generator as in MEP-004a. The second A and the S stand for "Acoustic Suppression"

 

[FormerNewMVGuy]

I am watching this thread very closely. I have recently aquired a PU-794/g from GL. it is a modified mep-004, I also have plans to rewire for house hold use.
A close friend of mine is an electrical engineer, and he seems to think its very doable,
I f i come up with anything before i see it posted here i will share the info.

It is modified from 15 kw to 20 kw, with the acoustic suppression kit , to 65 db. the original design was to power comm shelters on the move or stationary, it is also EMP protected

 

[DaveKamp]

Easy...

Green- it's not that complicated- house wiring is set up for 120/240 single-phase. What you have is 208/125Y. 120/240 is typically home, while commercial and industrial use 3-phase Y and 3-phase delta power.

On a 120/240 single-phase service, you have two HOT leads (L1 and L2) and a neutral, where one of the leads will be at +120v while the other will be -120... they're both alternating, and always 180 degrees out-of-phase.

In a 208/125Y, you have three legs, each 120 degrees out-of-phase. If you measure from any leg to another leg, you'll see 208v. If you measure from any leg to NEUTRAL (the center of the Y), you'll see 125v.

The simple fact, is that most devices you have in your home, work perfectly well in light commercial environments... that's because 200VAC devices are designed for 220vac +/- 10%. That manages both 208 and 240v with no problems. Connect L1 to one busbar, L2 to the other, and cap off L3, connect Neutral to your neutral busbar, and fire it up.

Purists may argue that a single-phase 240v machine won't 'like' the fact that the two legs aren't 180 degrees out of phase, but in reality, the machine doesn't typically 'know'.

I guarantee that this will work, because my ex-USN Kohler 15kva unit feeds my home with two legs and neutral of 208/125Y to an otherwise 120/240 single-phase house.

Re. wiring the 12-wire generator head for 'double delta'... this WILL work, and you'll see a slight improvement in output, however, it might be worth more to simply devote that entire third leg to running critical single-phase loads like sump-pumps, emergency lighting, etc.

As for making protected cross-connection, there are now UL-listed 'generator backfeed interlock kits' available for most popular service panels- they consist of a metal plate that blocks (alternately) the main and GENERATOR FEED breakers, so that it isn't possible to have both on simultaniously. This is dramatically cheaper than a transfer switch, and they work just dandy. You install the interlock kit, then install a suitable double-pole breaker to panel, connect the generator leads to this breaker, and you're good-to-go.

 

[Ferroequinologist]

Anymore information on this? I got a Mep-004aas from Richmond for my boss's farm. I'm working on getting it operational and will be wiring it up so she can use it as back up power (she lives in the middle of nowhere by herself and the power goes out all the time)

So any information on rewiring would be nice, also I need manuals, and does anyone have the fuel filters and oil filter numbers and where to get them? someone pulled the filters out of it.

Thanks!

 

[mdlbldrmatt135]

IIRC the ASK & AAS are the "silencer" surrounds

 

[GreenMachines]

Hello Ferroequinologist. Long name! Rather than rewire and risk problems I just wired some Receptacles on the front to make it user friendly. I think I have a mep 004 pic in my albums. I ran 120 to the receptacles on the left side and 208 to the receptacles on the right. Almost any device will run on 208 or 240, just more efficient on 240. If you really want to get 120/240 you could use a device called a buck/boost transformer, that will boost the 208 up to 240.

Anymore information on this? I got a Mep-004aas from Richmond for my boss's farm. I'm working on getting it operational and will be wiring it up so she can use it as back up power (she lives in the middle of nowhere by herself and the power goes out all the time)

So any information on rewiring would be nice, also I need manuals, and does anyone have the fuel filters and oil filter numbers and where to get them? someone pulled the filters out of it.

Thanks!

 

[Ferroequinologist]

Ok, thanks. Do you know a good place to get the filters? I've gotten the manuals downloaded.

 

[GreenMachines]

If you found manuals, they should have part numbers for the filters. You can go to WIX , Fram or brand of your choice and cross the numbers over!

 

[Ferroequinologist]

Thanks, just checking as not everything crosses over to civi I've found. I have the numbers and will call around for the filters.

 

[GreenMachines]

You can try the internet also, the filters are not military specific. They are industry standard items. I have used the WIX website to cross numbers and sometimes the part numbers in the manuals have extra digits and you have to try to cross them multiple ways. You can usually get filter application and cross reference information on a CD. Both WIX and FRAM where more than happy to send them to me. Good luck.

Thanks, just checking as not everything crosses over to civi I've found. I have the numbers and will call around for the filters.