Posted: 2/11/2012 6:59:25 PM EDT
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How large of a generator would I be able to run with a 350 chevy motor?
I have a good running 350 chevy and was brainstorming a use for it. Will probably convert it to run natural gas. Manufacturing a coupling shaft from the engine to the generator won't be a problem. |
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Fuel efficient it will not be. It will either turn 1800 or 3600 RPM for the duration of electrical output. Good idea but the fuel to feed the motor matched with a large head would use alot of fuel. Some of the 60KW use a Chevy 4.3 and its screaming. I know that a diesel would be more efficient, but the 350 I have was free and runs good. I was thinking about a 30kw head. I need 220v single phase for whole house emergency power. We have localized power disruptions from time to time mostly from bad storms and I would like to run my house, one 3 ton refrigerated hvac, and water well. |
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To address the OP's original question, the conversion is 1HP=747 watts. Minus something for efficiency. To keep it simple, let's assume that you could get 500 watts per horsepower, at whatever speed the engine needs to be driven to run the genny.
This holds pretty true with the smaller ones. 5KW gensets usually have 10-horse motors, 4kw 8-horse, etc. |
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To answer the original question:
In an automotive application, the engine horsepower rating is peak HP and you could not sustain that for very long without blowing up the engine. Think about it, you can't drive with your foot to the floor all the time. Given that, I have compared quite a few automotive engine specs to their generator counterparts and have concluded that a given engine in a car is rated for a given HP at about 4500 rpm. That same engine in a generator will have its HP rated at 1800 rpm and power will be 2.5 - 3 times less than its automotive counterpart. 746 watts = 1 HP. Frictional and heating losses will allow the average generator to output 500 watts for every engine HP. So for example, if a gas 350 from a car makes 210 HP @ 4500 rpm, the it will be rated for about 70 HP @ 1800 rpm and will be able to drive a 35 kW genhead. |
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So for example, if a gas 350 from a car makes 210 HP @ 4500 rpm, the it will be rated for about 70 HP @ 1800 rpm. Naturally, there's no reason why a 2-pole 3600 RPM alternator head couldn't be used instead - Or the alternator could be geared or pullied so that the engine runs at whatever speed you desire. |
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I would sell the 350 and buy a generator. Anything that is properly sized to a 350 will be overrated for any typical residence. I've seen 100kw gensets paired with NG fired 350s. If you put a smaller generator head on it you will be wasting fuel at a horrible rate.
Sell the motor on craigslist and buy something better suited for what you need. For example I bought a 6000 watt Winco generator with an electric start Honda Tri-Fuel motor on craigslist today for much less than its original $1800 price tag. Grove |
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I would sell the 350 and buy a generator. Anything that is properly sized to a 350 will be overrated for any typical residence. I've seen 100kw gensets paired with NG fired 350s. If you put a smaller generator head on it you will be wasting fuel at a horrible rate. Sell the motor on craigslist and buy something better suited for what you need. For example I bought a 6000 watt Winco generator with an electric start Honda Tri-Fuel motor on craigslist today for much less than its original $1800 price tag. Grove I may do that though I don't think a 6k is going to do what I want. I am thinking about 15k. |
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15kVA is about 20 horsepower, if converted with perfect efficiency. Figure 30-40 HP needed from the motor to run it comfortably.
Your 350 should do that with ease. Don't forget that you need a speed controller for the motor. If I recall, portable gensets in that range have around a 1 liter motor. |
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I would sell the 350 and buy a generator. Anything that is properly sized to a 350 will be overrated for any typical residence. I've seen 100kw gensets paired with NG fired 350s. If you put a smaller generator head on it you will be wasting fuel at a horrible rate. Sell the motor on craigslist and buy something better suited for what you need. For example I bought a 6000 watt Winco generator with an electric start Honda Tri-Fuel motor on craigslist today for much less than its original $1800 price tag. Grove I may do that though I don't think a 6k is going to do what I want. I am thinking about 15k. I have a 16kw Generac on my house and it is big time overkill. For my mothers house with 3 HVAC zones it is great but for mine it's a propane waster. I bought it before I really did my research on generators. FWIW since then I have purchased generators for each of our business locations and all of my family members. If you want to post the details on your home I would be happy to try and help you avoid the mistakes I made. There are many others on here like AR-Jedi that are much more knowledgeable than me that will help as well. Grove |
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I would like to run my house, one 3 ton refrigerated hvac, and water well. Do you want to run every single appliance in the house simultaneously? Do you want to run the HVAC and water well simultaneously? I do want to run HVAC and water well simultaneously. Electric water heater too. |
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My first thought is a gear drive to increase output rpm...I have no idea if this is really something to consider but thats what came to mind. So you could run the Rpms at say 1000 and get output Rpms of 3000...would that work in any way? Belt drive would be easier to do. |