Homebuilt Generator

Homebuilt Generator

PostBy: vwgtiman On: Fri Oct 23, 2009 11:33 pm

I am looking to build a genset using an ST type head w/4 pole 1800rpm and am wondering if the HP requirements are halved if I am going double the RPMs and having it to 1800 RPM via a belt.
vwgtiman
 
Stove/Furnace Make: EFM-350 Losh-475

Re: Homebuilt Generator

PostBy: SMITTY On: Sat Oct 24, 2009 1:08 am

Doesn't it need to spin at 3600rpm in order to achieve 60Hz?

I would have to say a 50% gear/pulley reduction should half the horsepower requirements - makes sense to me. I'd get a 2nd opinion from someone smarter than I though....just to make sure.
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Homebuilt Generator

PostBy: oros35 On: Sat Oct 24, 2009 2:05 am

SMITTY wrote:Doesn't it need to spin at 3600rpm in order to achieve 60Hz?

Nope, with the right number of poles you can make it go slower.

Looking at it this way, Horsepower is equavlent to watts through a conversion. 1HP=745watts

So say you want 5000watts of output you would need about 6.7HP. You will require a different torque though. Through conservation of energy you only get out what you put in.
oros35
 
Baseburners & Antiques: 1912 Smith & Anthony Hub Heater #215
Stove/Furnace Make: Smith & Anthony Co.
Stove/Furnace Model: #215 Hub Heater


Re: Homebuilt Generator

PostBy: Freddy On: Sat Oct 24, 2009 7:12 am

vwgtiman wrote:am wondering if the HP requirements are halved if I...


If you want to plow a foot deep the horse remains the same size regardless of how fast or slow you ask him to walk.
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Homebuilt Generator

PostBy: gaw On: Sat Oct 24, 2009 7:24 am

Usually a 4 pole generator is powered by a diesel engine running 1800 rpm. Larger generators are usually 4 pole and smaller ones are 2 pole, my guess for the reasoning is to better match them to the engines driving them. A 4 pole may be a bit more durable because it turns slower but I do not know if in fact it is more durable.

As “oros35” posted watts and horsepower are directly related. When buying tractor PTO powered generators the rule of thumb is 2 horsepower per thousand watts. The most common tractor PTO shaft turns at 540 RPM and has to be geared up to 1800 or 3600 RPM. This has no effect on the power required; the output of the generator determines that.

Short answer; no magic to be found in speed reduction, buy enough engine to match the generator output.
gaw
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice from Schuylkill County

Re: Homebuilt Generator

PostBy: wlape3 On: Sat Oct 24, 2009 8:19 am

Makes sense to me. Power in equals power out plus efficiency losses. Looking at buying/rigging up a generator myself.
wlape3
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: 140 auger, forced hot air

Re: Homebuilt Generator

PostBy: SMITTY On: Sat Oct 24, 2009 1:32 pm

Freddy wrote:If you want to plow a foot deep the horse remains the same size regardless of how fast or slow you ask him to walk.

Great analogy Freddy! Now I understand completely. If school was taught that way I'd have been a straight-A student! 8-)

gaw wrote:Usually a 4 pole generator is powered by a diesel engine running 1800 rpm. Larger generators are usually 4 pole and smaller ones are 2 pole...........

Now I understand. Double the poles & you can halve the RPM & still get 60 cycles. Never thought of that! Learn something new every day. 8-)

Not to hijack, but I just got a smokin deal last week on a Yamaha EF6300iSDE inverter generator. Was a bit of coin, but at 40% off the out-the-door price of a local dealer - AND SHIPPED TO DOORSTEP - , I HAD to jump on it! My old gen is already gone! But the whole point of posting this, is that the engine is 32cc's smaller & has 4 LESS horsepower than my old gen - goes against the 2hp rule that I've always gone by - but is rated for the same 5500W nominal power. That's some kick-ass efficiency right there!! :o This one has a 6300W max vs. the 6500W. http://www.yamaha-motor.com/outdoor/products/modelhome/622/0/home.aspx

Can even order an optional remote start for it! :lol:
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Homebuilt Generator

PostBy: 009to090 On: Sat Oct 24, 2009 1:40 pm

SMITTY wrote: I just got a smokin deal last week on a Yamaha EF6300iSDE inverter generator. Was a bit of coin, but at 40% off the out-the-door price of a local dealer - AND SHIPPED TO DOORSTEP - http://www.yamaha-motor.com/outdoor/products/modelhome/622/0/home.aspx

Smitty, Thats a nice gen! What was your final cost?
009to090
 
Stoker Coal Boiler: EFM 520 HighBoy
Hot Air Coal Stoker Stove: DVC-500 x 2
Coal Size/Type: Anthracite Rice

Re: Homebuilt Generator

PostBy: cArNaGe On: Sat Oct 24, 2009 1:55 pm

Sooooo talking about generators here. How are those PTO driven ones? I know the tractor takes alot of fuel and all but price vs output looks pretty good.
cArNaGe
 

Re: Homebuilt Generator

PostBy: SMITTY On: Sat Oct 24, 2009 2:25 pm

Chris you have mail... ;)

If I had a tractor with a PTO, I would have went that way in a second. You can get a 10,000W gen for a tenth of what I paid for the 6300W Yamaha. I always wanted to build my own out of an old dirtbike engine or find a way to rig it to my G110 with the 25hp Kohler v-twin. This Yammie is sweet though - would be tough to part with it now.
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Homebuilt Generator

PostBy: Yanche On: Sat Oct 24, 2009 10:11 pm

In my opinion the ideal generator is 6-pole. 1200 RPM operation gives you 60 Hz power. Nice quite operation especially with a water cooled engine. Barely above an idle.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Homebuilt Generator

PostBy: vwgtiman On: Sat Oct 24, 2009 11:00 pm

I was toying the idea of a low speed lister (800 RPM) but the shipping on one is out of this world. I have 2 Yanmar L100's and figured I would try to run them at 1800 instead of 3600 and save wear, noise, and fuel by running a 4 pole ST 5 or 8kva head.
vwgtiman
 
Stove/Furnace Make: EFM-350 Losh-475

Re: Homebuilt Generator

PostBy: Freddy On: Sun Oct 25, 2009 6:10 am

Just recently I was given a 15 thousand watt PTO generator. I hooked it up to my little Kubota & it seems fine. Other than testing I've not used it. I love the idea of having a generator and not having another engine to maintain. I think the diesel will be about as efficient as anything. Yup, the PTO is 540, generator 3,600 RPM.

I've never heard of the "2HP per 1,000 watts", but it seems close. I know my 16 hp Kubota won't drive the generator to full capacity, so with the 2 to 1 rule I guess I might get 8,000 watts. I was figuring 10k, but 8k will be plenty.
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Homebuilt Generator

PostBy: 009to090 On: Sun Oct 25, 2009 8:28 am

Freddy wrote: I've never heard of the "2HP per 1,000 watts", but it seems close. I know my 16 hp Kubota won't drive the generator to full capacity, so with the 2 to 1 rule I guess I might get 8,000 watts. I was figuring 10k, but 8k will be plenty.

Freddy, your kubota probably has closer to 14 PTO-HP. Theres a loss to the PTO.
009to090
 
Stoker Coal Boiler: EFM 520 HighBoy
Hot Air Coal Stoker Stove: DVC-500 x 2
Coal Size/Type: Anthracite Rice

Re: Homebuilt Generator

PostBy: coaledsweat On: Sun Oct 25, 2009 9:21 am

Freddy wrote: I've never heard of the "2HP per 1,000 watts", but it seems close. I know my 16 hp Kubota won't drive the generator to full capacity, so with the 2 to 1 rule I guess I might get 8,000 watts. I was figuring 10k, but 8k will be plenty.

My 16 HP GENRAC puts out 9000 watts at surge, I think about 8000 continuous. It will run the arc and mig welders, more than enough to keep the coven of witches here in WII, TV, coffee, hair dryers and curling irons. Not to mention warm and watered. :)
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea