Thread: Stepper motor as a generator??
Did someone try to use stepper motor as a generator?
When you connect a coils leads together it's quite hard to turn a shaft. Just wonder how good it will do as a generator eg.windmill.
They do act as a generator and i have had people buy them for this, but the problem is they make a lot of noise.Visit Us: www.zappautomation.com
The detent torque is too high to make it useful for a wind turbine. Also what rpm do you need to get a decent voltage...I suspect it's a reasonable amount.
There's better ways - make your own with neodymium magnets and copper coils. I've made a couple for wind turbines, will post a couple of pictures in a minute.
I think someday I'll give a try for stepper motor generator. Just for try or rather fun. I have idea stuck in back of my head to make a windmill. The only concern can be shaft thickness to cope with a rotor but tooth belt reduction and rotor on its own shaft can sort this problem out.
Gary: my neighbours got used to some weird noises blasting from my backyard and I can only hope a stepper motor generator won't over-exercise their patience :)
If you're thinking of making a wind turbine then you might be interested in the (roughly) 1kW generator & variable pitch wind turbine I made:
(In no particular order)
The good thing with making the generator this way is:
- It's coreless, so no cogging = low cut-in speed. Energy density/efficiency is worse, but you make up for it with big strong magnets.
- Since you're winding the coils you can get the right voltage without gearing (less maintenance and SIMPLE).
My wind turbine does use a wind turbine, but not for the generator. It's to vary the pitch of the blades via a worm drive and bevel gears:
As you can see mine (along with many others) uses a hub (like a trailer wheel hub, except I made one to fit better) and tapered roller bearings. That means the rotor is mounted on six M12 rods which is plenty strong enough.
The reason I made my CNC router was to make the blades (3.1m diameter) for this wind turbine....which I've still not done as I keep changing my mind.
Jonathan, that's one of or more likely the best DIY turbine generator I've ever seen but I'm afraid my budget couldn't handle this project and put my skills to the test :).
I honestly thought about VAWT- there are some advantages of this kind of turbine- especially in urban turbulent winds. They are slower than HAVT so they require generator to kick at lower rpm, but without messing with some kind of reduction bigger dia generator (more magnets and coils thou) of your kind from previous post would perfectly do.
What do you think about VAWT Jonathan?
[QUOTE=wiatroda;23291]Jonathan have a loot at this video, It nicely shows how turbulent wind is in urban area.[/URL]
The thing is it will vary for each site, which in my opinion makes discussing in general terms not very productive.
The VAWT in that video is a drag based machine (so TSR<1), so is inherently inefficient compared to any HAWT, and better VAWTs. At a higher windspeed (which after all is what we're interested in since power is proportional to wind speed [b]cubed[b/]) the turbine with TSR>1 (i.e. VAWT or HAWT with airfoil profile blades) will generate much more power. If the wind is turbulent then I think neither of this type will be that effective since when the wind is coming from many different directions the resultant force on each 'section' of the blade will be different - so the overall torque may not be that much. So that implies that yes a drag based VAWT would work better than HAWT in turbulent wind, but still not generate much power as it wont benefit from higher windspeeds. Also in tubulant winds fatigue on the VAWT blades, which are already highly stressed compared to a HAWT, will be greater possibly leading to faliure.
I tend to agree that VAWT should be better in turbulent wind, just from common sense. I think that it's not worth considering having a wind turbine if your site is very turbulent (unless you don't need much power, say off grid). However if you've made it yourself, and therefore very cheaply then why not experiment... design the generator so you can try VA and HA with the same swept area and compare.
If the wind is that turbulent then you should just put the turbine higher, and use a HAWT. Granted planning permission is an issue, but it's clearly the best way.
Also in the video it says 'The HAWT will turn in lighter winds so it it more efficient' ... which is a bit of a dodgy statement.
Last edited by Jonathan; 08-08-2011 at 08:59 PM.
That's what I thought to build, both HA and VA and compare performance ( generator can be the the same to cut costs and make whole experiment more data accurate) .
Permission makes me hesitate to build either one of them but the idea is still in back of my head. My garden location is very turbulent place and that's why I consider VAWT more appropriate for this location. Lots of reports say vawt doesn't need tower to be so high as havt so there is less risk it will fall to neighbours' gardens :). When I have some spare time (or money) I think I'll play a bit with stepper as generator and to control load by PWM proportionally to rotor RPM. Just an another idea.
Anyway, your generator looks superb. When are you going to put it up?
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