I've got a line on a low-hour military surplus DRASH GET trailer. I'm not sure yet if the HVAC capabilities are still functional, but that's neither here nor there. I'm looking at it for its power generation, although I did tell my wife that I could provide 96,000 btu of air conditioning when we go camping.

I know a 30-35 kW set is a bit of overkill, but this unit would be cheaper to purchase than any MEP003A or similar I've been able to find, so I'm considering it. Add in the fact that it is trailer mounted, and it becomes very appealing to me.

Question: Does anybody have any experience using a 3 phase gen set as a shore power solution for single phase applications? I know there shouldn't be a problem with any 120v appliances with a single pole tapped. I still have to go through my 240v appliances (mainly the A/C compressor, everything else is resistive) and see if they are rated for 208v power.

Another concern is with wet stacking. If I am using only 2 of the 3 poles, then right off the bat I can only load it to 20 kW at full capacity, on the off chance that I need that much power. More than likely, I'll be setting around drawing 6-8 kW of power at any given time. Does anybody with experience think a 1/6 load on the John Deere diesel will produce enough load to prevent wet stacking? Aside from the obvious efficiency disadvantages, will a 6 kW load on a 30 kW set cause engine damage long term?

Lastly, I could reconfigure the set for single phase. This would solve any 208v compatibility issues, but it would do nothing for my wet stacking concerns. Perhaps I need to recruit my neighbors to consume some of my excess power during any outages to increase my static load. I'm sure that as soon as I did this, I'd find something that needed 3 phase, Murphy's law and all.

I would like a useful purpose for this project, but in a significant way, I'm playing around here. And I do love burning diesel fuel. If we had hurricanes in Utah, I could power 4 of my neighbor's homes for a week and be a hero.

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If we had hurricanes in Utah, I could power 4 of my neighbor's homes for a week and be a hero.

Feel free to come to hurricane country. They might even put you on TV.

Yeah, you need to find out about your 240 equipment and see if it’s also rated for 208

Diesel generators need to be under a 60% load or greater to avoid wet stacking. If you can’t get there, I would forget about this generator.

You can get a step up transformer to boost the 208 volts to 230. Marina's do that all of the time. The transformers aren't terribly expensive.

As for load, you can get away with as little as a 40% load without glazing cylinders as long as you can get the load up to or over 60% for an hour every 6-12 hours

I really cannot see how your load would be only be around 6kw with HVAC going and say a normal 3 bedroom house with the various other household items.

^^Winter and assuming the gas service is working. Gas heat, gas hot water. Summertime, I’m sure I’d be ok with A/C. Where would I source a step up transformer?

Don't forget to consider fuel consumption and storage.

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Originally posted by sigcrazy7:
^^Winter and assuming the gas service is working. Gas heat, gas hot water. Summertime, I’m sure I’d be ok with A/C. Where would I source a step up transformer?

Grainger, other electrical supply places.

Hook up your neighbors and ask for help paying for the fuel? I suspect they'd have power outages the same time you did, and would like to have the backup.

flashguy

Just had an idea. For winter usage, I could just keep a half dozen electric heaters around, and that would essential act as a load bank. Switch to electric heat basically.

How many neighbors and roughly how close by?

From the middle of the cul de sac, I could get to myself and two neighbors with 75 foot drops. The fourth neighbor would require about 125’

The biggest issue with single phasing a 3 phase generator is heating in the rotor caused by negative sequence current. Most generators (ones that I'm used to anyway (1-3 MW)) can handle about 8-10% negative sequence current.

With the a single phase load the negative sequence current will be 1/3 of the load current.

A 35 kW 3 phase generator is rated for about 98A per phase (at 208 V), so the limit on output to keep the rotor from overheating is 0.08*95A*3 = ~24A continuous. My concern would be long term use can overheat the rotor and damage the insulation. I'm also used to bigger generators, so I could be totally wrong for this application.

I wonder if you can change the stator from 6 poles to 4? Probably expensive as hell.

I’ve seen some videos of guys reconfiguring a MEP003A generator for single phase. Changing the “Y” setup to what this guy called a zig-zag, or something like that.

Here it is