Genset question, 400 Hertz MEP-114A

[gonorth]

I messed up and won an auction on an MEP-114A 30KW genset. I saw it was 3 phase and figured no big deal, I know enough farmers that have 3 phase that could use it. I did not notice that it was 400 hertz until after I got the invoice.

Is there any way it could be changed to 60 Hertz and maybe even single phase 120/240? I am guessing that would mean to replace the generator.

Maybe I should just not submit the EUC and pay the 25% penalty to get out from under this scrap metal.

Or, is there anyone out there interested in it?

 

[Isaac-1]

The short answer is the 400 hz units are useless unless you need a run a big resistive load (electric heating elements, light bulbs etc. Nothing with a motor in it). Conversion to 60 hz is not practical (replace generator end, plus generator controls, etc.), all these are really good for is the engine for a repowering project, etc.


sorry
Ike

 

[Carl_in_NH]

Unless you really need the engine to repower or repair another genset, I think you've hit upon the correct answer; pay the 25% fee and be done with it - unless it was so inexpensive that you don't mind having it around.

Some folks in the aircraft world can make use of a 400 Hz genset - but typically not one of that size; a much smaller one can be a useful source of power for testing equipment on the bench. 30 KW is mighty big.

Sorry to reaffirm bad news.

 

[FMJ]

Let me guess, you bought that really nice looking low hour unit from Santa Fe NM?

 

[steelandcanvas]

Don't feel too bad, you're probably not the first one to do that.

 

[Speddmon]

I'm sorry to say, but for the cost of changing it over to something useful, you may be better off taking the hit and paying the fee. Unless you got such a great deal on it that you could scrap out the generator portion and sell off other parts to make up your money.

There really isn't any practical way to make anything useful out of these sets...A frequency converter is VERY expensive. And then you still have to deal with the fact that these sets are made to run strictly 3 phase only, so to get any usable 120/240 single phase you would need to do some rewiring and thereby de-rating the output as well.

sorry to hear about such a costly mistake

 

[gonorth]

Dang, I thought that was what you experts would say. That's the last time I will ever shoot from the hip with a bid on anything. Looks like a $550 lesson that I won't forget.

It was the one from Iowa that was on a sealed bid. With tax and fees it is costing me about $2500 plus a 400 mile round trip ride to pick it up. I don't have any practical use for the power unit and case unless I could find a cheap generator that hooks to a tractor via the PTO and somehow mount that in this unit. Even then I suspect they turn at 580 RPM and I would guess this diesel engine runs at around 1800.

 

[Speddmon]

most of the PTO generators are actually 3600 RPM heads attached to a 7:1 gearbox.

It still baffles me as to why a pretty much useless 400 Hz generator brings so much money.

 

[tennmogger]

It's not a total loss. Think about the situation with 400 Hz feeding 60 Hz stuff. It only matters if the load is frequency sensitive, like motors. Any heating elements, many lights (incandescent for sure, florescent maybe?), transformers, etc, will use the 400 Hz just fine and run cooler because of it. You could run a transformer type welder from that 400 Hz generator. I have a little 400 Hz inverter, 24 v in , 115 vac 400 Hz out, and it runs my computer just fine, and charges my cell phone. Switching power supplies convert to DC first anyway, then to AC for boosting or bucking the voltage, then back to DC. The 400 Hz input is easier to filter.

400 Hz was originally used because higher frequencies allow lower mass in transformers. But that's the reason you can't use 60 Hz on 400 Hz transformers, there's not enough mass at the lower frequency. That incompatability tends to make people think 60 Hz stuff will not work on 400.

Motors use line frequency (and number of poles) to set their rotating speed so motors will not run at the higher freq.

FWIW, YMMV,

Bob

I messed up and won an auction on an MEP-114A 30KW genset. I saw it was 3 phase and figured no big deal, I know enough farmers that have 3 phase that could use it. I did not notice that it was 400 hertz until after I got the invoice.

Is there any way it could be changed to 60 Hertz and maybe even single phase 120/240? I am guessing that would mean to replace the generator.

Maybe I should just not submit the EUC and pay the 25% penalty to get out from under this scrap metal.

Or, is there anyone out there interested in it?

 

[Carl_in_NH]

Remember - he's talking a 30KW genset here; running a few items that have DC-DC converters internally that rectify the line voltage into DC and then switch is one thing, but typically with a genset this large you want to run a whole house or farm. Segragating your loads into ones you can run at 400 Hz vs motor loads isn't typically worthwhile at this scale.

Also be advised all transformer loads are not the same - some 60 Hz transformers get very inefficent because of core losses when you try to run them at 400 Hz. There are also feroresonant transformers that won't be happy at all running at anything but the design frequency. Motors are not the only problem.

Bottom line - for this size generator and typical intented load (I am assuming you want to run an entire hours or business with a 30 KW set), it's best to get out from under this purchase and buy what you really need. Jumping thought hoops to make something workable isn't what you want in a backup power source. Simple is the key to reliable power when you really need it.

 

[goldneagle]

I bought a 15 KW 400hz gen set a couple of years ago. It was missing some of the control components for the generator head. I got it real cheap for the engine and trailer. I bought a 42 KW Marathon generator head and installed it on the engine. Generator head set me back $3000. Now I have a really nice generator that can power my house during hurricanes. the generator head can be attached directly to the engine once you figure out the NEMA numbers for the flywheel and bell housing. You order the generator head to match. I was not going to buy the 42KW head but it was the smallest available that would match up to the engine.

 

[Isaac-1]

I am not sure how you feel about your time vs. money, but at $2,500 or so you could probably scrap out the generator end (copper, etc) for a few hundred dollars, and make your money back off selling off the engine. This is assuming it is in good condition.

Ike

 

[pctrans]

OR, you got one hefty boat anchor! Don't feel bad, i got one too. But it has saved me a lot of money in parts fixing up other gensets.

 

[Coldfusion21]

It still baffles me as to why a pretty much useless 400 Hz generator brings so much money.

I agree. I was watching one a few weeks ago up at ft lewis. Dang thing went for 1300 dollars i think. Wonder if they knew...

 

[Isaac-1]

$1,300 or so makes sense to me, just take a look at ebay for asking prices on running used industrial diesel engines in this size range. At the moment there is a "running" White D198 from a military generator (probably 20kw) with an asking price of $1,500 and it just goes up from there. I don't know what other equipment used this same model/family of engines, but old generators are a popular source for engines to repower all sorts of industrial equipment, tractors, motor graders, dozers, etc. since they tend to have relatively low hours, and be well maintained. At $1,300 even not running it might be worth it to the right person for engine parts, or a rebuild core, I suspect a working used injector pump from one of these is worth at least $300-400 alone.

 

[gonorth]

Thanks for all the input. Sounds like this would be a great genset for someone needing lots of lighting at a construction site.

Yes my intent was to run two homes, mine and my neighbors. Being able to run motors is essential for my intended purpose. For example the well pump, septic pump, and furnace. (actually we should run a third house on the third phase, I have a seperate heating service panel so I would have probably put it there)

Why do these bring big money? In my case I was stupid, didn't see the 400 hertz even tho it was right there and it was a sealed bid. I made a quick bid and forgot about it till I got the winning bid notice. I bet a lot of those other cases are also mistakes.

 

[Isaac-1]

It makes no sense to me why many things sell for the prices they do on GL, sometimes that is high, sometimes it is low. With these 400 hz generators I suspect a fair number are to people that don't know better, or like you did not read the fine print. I can see some people needing only resistive loads buying them because if they were selling a good bit cheaper than the 60 hz sets, I just can't see that much demand. Maybe there is some nitch industry where they work great, like mining, or such where the higher frequncy saves weight in wiring when running very long strands of lights.