Harbor Freight Generator head 10kw

[v8dave]

4-pole generator heads will spin at 1800 rpm to get 60 Hz AC power. A 2-pole generator head will spin at 3600 rpm for 60 Hz AC power. It's easier on engines to run them at 1,800 rpm which is why the 4-pole generators runing at 1800 rpm are more likely to be found in 24/7 application.

Not to say that 3,600 rpm generators won't last a while when running 3,600 rpm. Kubota offers several Diesel gensets that run at 3,600 rpm and they are touted as being able to run 24/7 service. Although, I doubt they would hold up for a year's service that way. For stand-by, worksite and occasional use they work just fine.

I don't remember who first posted this formula from here on TBN. But, the formula is: NP = (F * 120)/RPM
or
Number of Poles = Frequency times 120 and divided by RPM

A thing to look for in building a belt powered genset is to be sure your generator head is a two bearing unit. Single bearing generators are intended to be mounted on the engine's bell housing/flywheel and use the engine rear main bearing to support the front (input) shaft of the generator. Two bearing generators are built to handle the side load a pulley drive will present.

 

[Jim_in_Omaha]

Something I'm wondering is,
If a person buys a 7kw head and runs continuous 5kw load, would it require approximately the same HP to run that same 5kw load on a large 12kw head? According to all the things I'm reading it would be about the same give and take for drive coupling and how efficent the head is.

The reason is because if I was to go with a ST head like off of Ebay I would probably go with a larger KW head just in case higher capacity is needed someday.
jim

 

[1962]

sure, you can do that. you can have a 20kw head, and it's only going to put out what you put in. the prime mover engine rating rule is 2 horsepower per every 1000 watts electric output. that is taking into factor altitude, heat, and other losses. so you could put a 12 hp engine on a 15 kw head and you will get 6 kw of useable power out of that set-up.

 

[Highbeam]

Plus, the larger than needed generator head will have bigger parts that weigh more to offer more of a flywheel effect for starting up higher loads. The parts are built and sized to handle the high amperage so they should hold up better than a 100% utilized smaller head.

 

[XmasTreeGrower]

Jim
Just to answer your original question; I purchased the same unit you are looking at from HF, and used it for 96 hours non stop during one of the hurricanes last year.

It performed flawlessly, handled my whole house, ran the computer and electronics OK, etc.

I personally find the 3600 rpm feature easy to deal with since this is the governed speed of almost all small gas engines. I threw a pulley on the front of the head, and used the PTO belt pulley from my Steiner tractor to power the head. Bolted the head down to a small pallet, staked the pallet down with some rebar, hooked up the belt, and away we go! Takes about five minutes to set up and take down. I am certain anybody could come up with any number of creative use of pulley sizes to get whatever ratio you need. In the case of my power plant, it was a simple one to one ratio. As was noted, a straight Lovejoy coupling off a horizontal shaft engine would be fine as well.

Incidentally, the Steiner has a 18 hp Briggs opposed twin, and it kept up fine at peak loads.

It takes up very little room in my shed, patiently waiting for it's next call to duty. It was definitely one of the best $300 bucks I have ever spent.

Thanks
Bill

 

[Jim_in_Omaha]

Thanks Bill..
Not sure what I'm going to do for the gen head. I got a price for a 12k Mecc Alta Italian made unit $525. It looks like the Northstar unit from Northern without the fancy output box. Just a junction box.

One thing I found was the display unit at the Harbor Freight store (which has been there awhile) said that the continous is 9.2kw with a 10kw peak. It looks just like the current #45416 with the same number. I wonder if they de-rated it at some point for the continous rating.

Did get the engine. Military standard 4A032-4 by Teledyne. Ran if for about 30 minutes. Held it down with 1 C clamp. Very little vibration.
thx
JIm

 

[Highbeam]

We must have pics.

 

[Jim_in_Omaha]

So far this is all I got. An engine. Its like a mini volkswagon flat four air cooled.
thx
Jim

 

[Highbeam]

That's great.

 

[TOMLESCOEQUIP]

Jim........Let me know how the engine works out for you...........I have the same engine, govt. rebuilt with 6 (test) hours on it. I got mine at a city auction about 10 years ago, test ran it & its been waiting for an application ever since.