Induction turbine

[Wayne103]

I was wonering if anybody is working on a induction turbine I have been working on one for about 4 years money permiting .I built a plug and a mould for blades 8 feet long 2.5 inches of twist built a 60 foot fold over pole work and avalible money slow but now I have all the parts maybee this summer I'll get it up and running.

                                                   wayne

[finnsawyer]

How does this differ from you find done by people posting here?  Please define your terms.

[Wayne103]

you'll have to excuse me I'm new to this what I'm working on is the same as the megawatt units but on a smaller scale

[Chiron]

Which generator type are you modeling it on? I know of 4 different types of induction generators used in MW+ size turbines.

[Wayne103]

I picked a guys brain down at ontario hydro about a 40 kw 600 v 3 phase wind turbine that was up and running at a hydro station and got a lot of good ideas from him.What I'm working on is 7.5 kw 240 v single phase.

[dustind]

I hope you post everything you learned. If politics and laws allow I hope to build a few large grid tied wind mills in a few years once I buy a house. Too bad you can only sell 70,000 KWH a year in NH IIRC.

[Wayne103]

ask questions I will answer the basic theory is if you thke a 5hp 220 v single phase motor plug it in,it will run at 1750 rpm's and draw minimum current,you load the motor down to 1700 rpm's it draws maximum current without going up in smoke.You take the same motor over spin it to 1800 rpm's while it's pluged in it becomes a sycrones generator in phase and at the proper frequency.

[Chiron]

What were you planning on using for phase correction and speed control?

One reason none of the currently built large turbines, or small ones that I know of, use solid rotors with the stator connected directly to the line is that once the generator exceeds synchronus speed, 1800RPM in your case, the power factor gets further from unity the faster it turns.

Same is true of a motor running slower then synchronus speed, that's why larger motors have run capacitors to correct the power factor on the line. Some older turbines like the Vestas V-15 used banks of switched capacitors to correct phase and power factor of the output.

You might want to check into what your local utility requires for power factor control on grid tied equipment. I know that here, MN/US, the power factor has to be within 0.25% of unity on grid tied equipment. Poor power factor control creates a lot of headaches for utilities both on the generation and consumption sides of the grid and they're getting pickier about it all the time.

If you Google "Power Factor" you'll find a lot more info

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[Wayne103]

I"m using variable pitch blades and a microprocessor for speed control

[Chiron]

Varible pitch on a 16' machine is a bit unusual. To my knowledge no (current) commercialy built turbine under 50kW uses varible pitch though years ago there were some 10kW units built near here that did.

I'm curious about how you plan to accomplish this. I live in the middle of a bunch of wind farms and though the overall NREL wind rating is 4 bordering 5 there is a lot of variation in winds from day to day and from season to season. I've been looking into different schemes for a variable pitch.

Right now a stepper motor on a rack and pinion looks most promising since if the motor, drive circuits or power fails it would fail safe and automaticaly pitch to 90 Deg.

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[Wayne103]

tThe way I built the blades there is a 4130 chromemoly shaft that is mounted in berings in the hub that allows abuot 40 degrees of feathering,one of the jobs of the eletronics is to supply braking if the blade feathering is not enough