More generator talk....

[tRidiot]

Winter coming. It's time for the annual generator thread, just like the State Fair Concealed Carry Thread. lol

Anyways, Sam's Club has a Black Max 7000w with a Honda motor for a grand. Not bad. Not a true Honda genny, but not bad. But I'm really looking for 10kw or so.

So I ran across some auctions for diesel generators from the military. A bunch out at Tinker that are not portable, but I can pour a little concrete pad next to the house and set a generator on it. What I've read is these things are rated for like 30,000 hours, whereas the gas-powered ones you buy from Lowe's and such are about shot after a couple thousand hours.

Any thoughts? Pros? Cons? Big and heavy, yes... so was my safe, but that was a good investment, I'm thinking this might be, also. And from what I have gathered, I can get them cheaper than the big-box units. May even be able to get a much bigger one for similar price - 15-20kw or so?

What say you?

 

[twoguns?]

Generac makes a really nice one 16kw I believe for about $1860......
It can even be connected to your house system when your ready......nat gas/propane

 

[cowadle]

I use an MEP 002A for my stand by set. military surplus runs 1800 rpm and sips fuel. I have run for over 30 days straight before ran whole house no problems, I have a 20 K MEP 005A that is surplus to my needs would trade for guns.

 

[Powerman620]

I have seen several mil surplus gen sets that the cycles were off, have them checked out before using

 

[tRidiot]

I have seen several mil surplus gen sets that the cycles were off, have them checked out before using

My neighbor is a licensed electrician who will be installing whatever I get. I assume this should be within his realm of expertise? If not, who/what kind of expert do I get to do this? Any tips on how to choose a good unit would be helpful. I could drive over to Tinker to look at them, but not being hooked up and just looking cosmetically, I don't know jack about these.

cowadle, that unit is likely way more than I need, unfortunately. Thanks, though. I need about 10kw, no more. Anything else would likely just be wasting fuel... even the 5kw would be fine if it weren't for central air.

 

[Shadowrider]

My neighbor is a licensed electrician who will be installing whatever I get. I assume this should be within his realm of expertise? If not, who/what kind of expert do I get to do this? Any tips on how to choose a good unit would be helpful. I could drive over to Tinker to look at them, but not being hooked up and just looking cosmetically, I don't know jack about these.

cowadle, that unit is likely way more than I need, unfortunately. Thanks, though. I need about 10kw, no more. Anything else would likely just be wasting fuel... even the 5kw would be fine if it weren't for central air.

Have you done the calculations? 10kw isn't a lot to be running a central AC unit on. But with that said, if your unit is a new model it may be fine if you are willing to leave stuff off and "cycle" their use while you are without power. My mom had a 14kw Generac put in and it will run her central AC, electric stove, oven, TVs, computer and some lights without issue. She basically doesn't have to even consider anything with it's smart switch.

Check all your appliance tags, they have the run load in amps on them somewhere. Add them up and you will need at least 20% plus a bit more extra to start them up. 25% should be plenty. But my point is that you can easily run yourself short if you try to go minimalist. When your power goes out it's a PITA to only be able to run like 2 things at a time, the tornados taught me this.

 

[SlugSlinger]

I would get the simplest unit you can find. I mean by that, the more automated controls it has the more likely something will fail and at the worst time. If you can find one that uses automotive relays and know how to replace them, you will be better off in the long run. I have dealt with a couple generator repairmen, one who had a masters degree in electrical engineering and that was his suggestion. They said stay away from residential generac because that is the make they have the most calls on.

I have a Kohler 18kw and the 200 amp automatic switch. The control board in the generator and the control board in the ATS both burned up at the same time. From what? I don't know , but there is a replacement/upgrade generator board. Kohler has a 5 year residential warranty that covered the replacement parts and labor, otherwise I would have been out a couple thousand bucks. And Kohler holds customers captive with parts and the programming of the generator.

Oh, and when the generator board went, nothing would work because it controls everything on the generator.

 

[Shadowrider]

That's odd SlugSlinger, I was told to stay away from Kohler specifically because the auto switches almost never work when you need them. From what I could gather at the time from lurking on some prepper forums and some reviews, it sounded like it was good advice. It seems that Kohler has a decent genset, but the controls suck.

 

[SlugSlinger]

I have no personal experience with generac, that was the recommendation from the 2 different repair guys. I can however vouch for the Kohler controls bringing the suck. I'm not worried about the switch as much as the genset controller. I can mannually engage the switch. I can't however run the generator if the controller fails. It literally controls everything on the genset, from the idle of the motor to the power output of the genset. If I had to do it over again I would not buy a Kohler.

That's odd SlugSlinger, I was told to stay away from Kohler specifically because the auto switches almost never work when you need them. From what I could gather at the time from lurking on some prepper forums and some reviews, it sounded like it was good advice. It seems that Kohler has a decent genset, but the controls suck.

 

[dennishoddy]

I have seen several mil surplus gen sets that the cycles were off, have them checked out before using

They could have been set up for European 50 hz or other countries.

My neighbor is a licensed electrician who will be installing whatever I get. I assume this should be within his realm of expertise? If not, who/what kind of expert do I get to do this? Any tips on how to choose a good unit would be helpful. I could drive over to Tinker to look at them, but not being hooked up and just looking cosmetically, I don't know jack about these.

A two pole Generator(common for most residential) has to run at 3600RPM for correct frequency.
One of the most common ways of changing the output frequency of a generator is to change the rotation speed of the engine.

The two factors are related as per the following formula –
Generator Frequency (f) = Number of revolutions per minute of the engine (N) * Number of magnetic poles (P) / 120
Conversely, P = 120*f/N

As per the above formula, a 2-pole generator producing an output frequency of 60 Hz has an engine speed of 3,600 rpm. To change the output frequency to 60 Hz for the same generator configuration, the engine speed needs to be reduced to 3,000 rpm. Similarly, for a 4-pole generator, an engine speed of 1,800 rpm produces output of 60 Hz. Reducing the engine speed to 1,500 rpm yields an output of 50 Hz.

Some of the old Diesel Generator power plants that municipalities had ran the diesel engines at 180 rpm with 32 pole generators. Ponca City is one of them. The engines are HUGE! Pistons are 36" in diameter and 6' tall. Typically 11-13 cylinders. They don't use them any more. My dad spent 36 years operating and maintaining them in the Ponca Diesel power plant. I worked part time there at night while in college.