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Onan Genset and wind power system conceptual


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  #1  
Old 06-22-2013, 09:52:18 AM
mronkar mronkar is offline
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Default Onan Genset and wind power system conceptual

I am working on the initial concept phase of a Onan Genset/ Windpower combination
System. This may seem a little “out of the box” to some, but I see potential for increasing the
Available output of any size Onan Genset.

First I want to go over using a 3 phase 480 VAC induction motor, similar to those used in an industrial manufacturing Facility as a windpower generator. Don’t nickpick numbers, were talking theory here.

This motor is driven by connecting it to the Public Utility Power System. It will rotate at the nameplate
Indicated speed, lets use 1800 rpm. It would be mechanically coupled to a gear reduction box and drive a wind rotor blade system. Lets use a rotor tip speed equal to a 6 mph wind., when there is no actual wind
Present.

Not a very efficient generator yet. As the wind speed increases and exceeds 6 mph, the rotor blades will
Be driven by the wind and the wind power would try to increase rotational speed. Any actual change would be almost none. Instead of increasing speed the induction motor will start generating power instead of consuming power. Still Not the most efficient system until you figure in the fact that you do not need an expensive phase sync controller, since your field windings were utility driven, the out will match that phase. And if utility power goes out, the generator stops producing power. No back feed into the utility which may cause injury to a lineman. I have heard some utilities have no problem with this type of wind power system.

Now I am wondering about this setup using NO connection to utility power, NONE. But using an Onan Genset as the initial source. Once wind speed increased to a point where wind power was generated. The load would decrease on the genset. Throttling down and saving fuel. As the wind speed would decrease, the genset would throttle up to meet the load demand.

Say a 7.5 JBFL with a 5 hp motor, this motor represents approx. 3750 watts at FLA and rated speed. With the right wind you would have over 10K max.

I haven’t started working out details, but one detail is what happens with no load and a wind speed that
Generates power. I don’t think you would want this back feeding into the genset. So having a load connected at all times might be desirable, just not practical

Anyone think this could actually work?.
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  #2  
Old 06-22-2013, 11:24:18 AM
Leon N. Leon N. is offline
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Default Re: Onan Genset and wind power system conceptual

Well congratulations! So I am not the only one thinking like you! Yes, yes this concept has merit. Two things come to mind that you probably are aware of. (1) You must have sufficient load on line at all times to act as the sink, if you will. If the wind speed increases too much you must have sufficient load so as not to back feed the generator because it is not an infinite sink like the utility grid. (2) If you use a 3 phase 480 volt motor, your Onan must also be a 3 phase 480 volt machine, otherwise you will have to add additional circuitry.
Why not keep the Onan as a separate, but reliable standby power source and back feed the utility 24/7 with a smaller set up? That way by running 24/7 continuously, assuming you are in a windy area you can slowly reduce your KWh draw from the utility. In either case you need a wind sening system to de energize the wind generator. During a no wind condition.

Hey, I have agonized over such a system for years, but it's not very windy around here.

Keep us posted and good luck!

Leon
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Old 06-22-2013, 11:26:24 AM
Radiomike Radiomike is offline
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Default Re: Onan Genset and wind power system conceptual

The use of an induction motor as a generator is possible and are widely used where the speed may vary. The motor will need to be driven somewhat faster than the nominal 1800 rpm to produce power. This wiki article is very informative.
http://en.wikipedia.org/wiki/Induction_generator

For high winds how do you propose to limit the power, power will increase as the cube of wind speed. Many wind power installations have tip brakes , pitch control or automatically turn away from the wind; as well as rotor brakes.

http://www.iowaenergycenter.org/wind...eed-and-power/

Mike

Mike
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Old 06-22-2013, 11:40:40 AM
len k len k is online now
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Default Re: Onan Genset and wind power system conceptual

Quote:
Originally Posted by mronkar View Post
Generates power. I don’t think you would want this back feeding into the genset. So having a load connected at all times might be desirable, just not practical
I don't know anything about using a motor as a generator. But on a conceptutal basis I think that you are right. As motor generates excess energy I suspect it will try to overspeed gen, gen really has no good way to disapate this energy. Not good.

Another idea might be a electronic controled variable load to disapate the excess energy. But if it fails likely so does the gen. What you're talking about is using the load as a speed controler for the blades. Also this is just fundamentally parrelled generators and all the problems that comes with that.

I would not relie on load as the only speed limiter, too many items to fail. Would want to see a more reliable failsafe on blade speed, so it doesn't self destruct in high winds.
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Old 06-22-2013, 11:52:20 AM
Gunny Gunny is offline
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Default Re: Onan Genset and wind power system conceptual

Think you have some good ideas.

How about this, all with current technology?

A 48VDC battery bank to store/buffer power. A wind generator to charge your battery bank. An Onan generator to maintain battery charge should the wind fail to keep up.
At the present Onan makes a small (5kW) genset powered by either propane or natural gas with a 48VDC output. Engine speed is dependent on actual load on the genset, rectifies a high frequency generator AC output to DC. Those gensets are (or maybe were) very popular with the telecommunications industry. Libby of welder fame made a lot of them for Onan in the late 1990's
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Old 07-18-2013, 12:02:22 AM
mronkar mronkar is offline
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Default Re: Onan Genset and wind power system conceptual

Sorry I wasnt able to get back to this sooner. Gunny you may indirectly have answered the back feed problem. By running a battery charging system, both systems would feed that load, and and would sink the power of the wind generator to protect the genset. If system is charged sufficently, shut down the genset and generator through a sensing circuit.

I was hoping to figure a way without a large battery expense, and inverter. But Like I posted it is all conceptual at this point.

Thank you to all who commented.
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