electric resistance heating w/ wind

[redneckmotherearther]

I'm new to this pc communication stuff...sorry..I have a question about using a 2000

watt ac generator head, geared correctly to a 10'or 12' 3 bladed turbine. Can you wire it directly to a electric heater that has no fan or controls? Will the slower speeds burn up or hurt the generator. My goal is use wind turbine directly for electric heater  1500 watt size in a thermal river rock storage system along with home built hot air collectors. I am doing my version of jacobs feathering system so i will have speed control on the unit.

[Flux]

You will need a substantial ratio speed increasing gearbox to get the speed up for a standard engine driven alternator.

I see many serious problems to be overcome with this idea. Conventional alternators are not inclined to excite much below nominal speed so you may have to be nearly up to your pitch control speed before anything happens. For a constant load resistor you will most likely have to hold load off until high winds when the thing is already in pitch control or the load will either stall the blades or more likely throw off the alternator excitation unless it has AVR control.

The end result is going to be pretty dreadful. To even stand a chance of making something respectable you will need quite a sophisticated controller with pilot exciter and some form of approximating the cube law load. Unless you are into power electronics then the scheme is pretty much a dead duck.

If you have the ability to do the blade pitch control then you would be far wiser to use a low speed alternator with permanent magnets and get a decent efficiency rather than have gearbox losses,alternator losses and a very complicated control scheme. Even with a pm low speed alternator you will not get very good results into a fixed load but the scheme may work with series capacitors or a 2 step load change. It will be significantly easier and safer than a furling machine if you have a pitch controlled limit on speed but for good power extraction you should do all the energy capture below pitch control operating point and just bring that in at the alternator power limit.

Flux

[redneckmotherearther]

thank you Flux...I feel i got a brain spanking...Im going to pay serious attention to the advice. Im fairly good with hydraulics and welding because I take care of most all my repairs in excavating but i did talk to several alternator shops and was led to belive i could use a generator head, like a 2000 or 3000 watt engine/pto driven and use it directly for electric heat.So my nexy question is...are there any diy plans that lay out how to do this i.e. what size of heat element to use with a certain size alternator, etc ? I don't read electrical schematics like serious

electronic engineer. Some of my 1980's wind power books made this sound easy.

Thank you for your time, it is appreciated  

[Flux]

The alternator shops you talked to were correct about an engine driven alternator that they would be familiar with. They would have no concept of the wind turbine bit and its limitations. With an engine the speed is constant and any power level uo to full load is always available.

With wind you can't extract more power than is available from the wind at any instant and the load has to match the available power.

There is nothing inherently difficult about wind power and heating but it does involve control circuitry to keep the load in track with available power. Battery charging is easier for those who don't want to delve into control circuits but even then for best results you have to match the load to the available wind power.

Look on this board, there is a certain amount on wind heating but rather limited.  There is some information from DaveB and Zubbly that I can remember and one of our Scandinavian contributors did something on capacitor load matching.

Flux