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windymiller
New Member
United Kingdom
60 Posts |
 Posted - 25/03/2008 : 09:15:44
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Hi Ben and everyone at gotwind.
Im in the process of modifying a car alternator to work as a cheap ready available motor to work as a wind turbine "efficiently"
I realize people have steered away from using this motor ,simply because it uses power to energize the field coil,which comes from your batteries!.......not good idea,for obvious reasons.
Ive done a bit of research on the field coil and what power is needed to bring it up to full saturation....about 40watts total (12v 3 amps roughly)
My idea is to use a "slave genny motor " mounted directly beneath on same scaffold pole, to generate this power.possibly a sturmey archer dyno (alternator) rectified to feed the field coil.( not strong enough in present form)
The dyno hub will be uprated to neo magnets which ive sourced and coming shortly.
If this does'nt work i might use a stepper motor instead.
The overall idea is to supply the rewound alternator with a variable power source(magnetic field) to the alternators field coil.
Initially the main turbine will suffer no start up problems what so ever(cogging etc),because there are no losses to hold it back
As wind speed increases the main turbine "gets up to speed" without much holding it back.
The slave genny now gets up to speed and energizes the field coil and makes the main alternator operational producing hopefully loads of power
The alternator regulator will be disgarded,...the power the alternator makes will be direct to batteries via rectifier /voltage controller
Im two thirds through completion.
Id be interested to hear from members if they can point out any obvious flaws that may ruin the project(im not perfect you know)
My main aim is to make a car alternator useable for a wind genny so everyone can have a go at making one.
Keep up the good work everyone
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Del
Junior Member
United Kingdom
362 Posts |
Posted - 25/03/2008 : 13:54:10
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Hi windymiller,
My initial thoughts on your project are that it sounds slightly complicated. Are you intending to link the two gennies by a belt or chain and have just the single bladeset? If you are then you will have friction losses that will be wasteful, although it depends on your wind availability - you may have more than enough?
What kind of rpm's have you calculated against what kind of output? And cost? The more usual route for car alternator use is to do what Beewind / Windblue power / Hornet do and use neo magnets and rewound stators (Windblue power sell their components separately).
Still, that said, I really like seeing new ideas and innovative solutions that are diferent to everyone elses so the very best of luck to you on the project.
Cheers
Del. |
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windymiller
New Member
United Kingdom
60 Posts |
 Posted - 25/03/2008 : 16:22:18
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Hi del, thanks for your reply its appreciated
The whole concept seems quite complicated at first glanc, buts thats probably me not explaining the whole project properly
My appologies.
The main turbine is a car alternator (delco remy)fitted to early cavaliers astras etc.
Rewound to "cutin" speed of around 400 rpm full field excitation.(12v)
The slave wind turbine is mounted on same scaffold pole and swivells round independently.
This smaller turbine will(energize)feed the field coil slip rings in the main alternator VIA WIRE along scaffold pole,to main turbine.(no pulley or chain drive).
Depending on wind speed both turbines will be turning.
The faster the wind ,the bigger the voltage to the main turbine field coil ,from the slave genny.
The lower the wind speed ,the less the slave turbine energizes the field coil in the main turbine...therby letting the blades get up[ to faster speeds without any resistance.
Ive done a few bench tests ,and it seems feesable!!.
Its a case af calibrating both gennys to wind speed to get best performance.
Hope ive been a bit more clearer...sorry if ive not
All suggestions will be listened to and appreciated
Cheers!!!! |
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gotwind
Forum Admin
United Kingdom
765 Posts |
Posted - 25/03/2008 : 21:14:41
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Hi windymiller.
Bit unconventional, using 2 turbines, most suggest going with a tried and tested method.
I think a converted Neodymium vehicle alternator would be more fruitful, they can be bought, Windblue power springs to mind as Del suggests.
I tried to neo convert the dynohub a while back, it was unsuccesful, cogging multiplied tremendously with the added flux.
http://www.gotwind.org/latest_experiments.htm
If you have access to a lathe and machine tools, maybe look at motor conversions or Hugh Piggott's axial flux design - great design, and again tried and tested many times over, worldwide.
Ben. |
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windymiller
New Member
United Kingdom
60 Posts |
Posted - 25/03/2008 : 22:51:34
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Thanks ben.. your comments appreciated.
One reason for not taking the easy route,was the cost really.
I have seen the alternator conversions with wind blue,and yes i agree they are more compact and simplistic,and probably the best choice for many who have turbine projects ,without question a brilliant choice from what ive read about them.
They are though over one hundred pounds,as you probably know.
Im in it for the fun,and enjoy every moment i spend with them.
Up to now ive probably spent around fifty pounds in total including the neo,s for the sturmey archer mod.
The cost of ametek motors are making it difficult to make a cost effective project,and becoming like hens teeth...everybody wants them!
Main turbine is three blade wooden design,which is already built and works well.(I carved the blades myself)
The slave genny is a five blade setup made from plastic blades mounted on an alloy hub,then mounted onto the sturmey archer hub ...blade pitch can be adjusted,similar to future energy blade setup,except much smaller .
Open voltage readings two weeks ago were reading as high as 40 volts and screeming its bearings off....no kidding!!
Can any one tell me whether there are iron losses,cogging etc with the wind bue genny at start up?.Id be interested to know
As ive already mentioned im trying to make a car alternator a ideal choice,because its so cheap and available to everyone.The challenge for me is to energize the field coil in the alternator from an independant source...not the batteries.
Im really optermistic about it working....ill keep you posted ...thanks for reading
Ps if you need any info about what ive done so far ...just ask cheers. |
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ghurd
Junior Member
USA
277 Posts |
Posted - 25/03/2008 : 23:42:46
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Cogging can be reduced to 0.
Iron losses will be present anytime a conductive stationary backing is included. Anything that is stationary and conductive has losses.
When the parts are copper and loops, then the losses are called "output into a battery".  |
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windymiller
New Member
United Kingdom
60 Posts |
Posted - 26/03/2008 : 12:05:52
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Thanks ghurd....not sure whether that was an answer with a sense of humer added or maybe having a "pop at me",.......so on this occasion ill choose to ignore it
I think your reply refered to magnetic permeability and emf/voltage
clarity.....and none ambiguous replies will help all readers to understand topics mentioned which im trying to do
Maybe ill just sit on the fence and become a lurker....less hasstle....you cant beat the quiet life
Kind regards windymiller |
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ghurd
Junior Member
USA
277 Posts |
Posted - 26/03/2008 : 15:26:09
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No, not a pop at you. Anything with stationary laminations will have losses from eddy currents, but not until after there is rotation. The thinner the lamination pieces, the better.
Fungus cut the laminations out of something to get less losses, and it really helped.
Cogging usually isn't a problem as long as the blades start turning at about 6 MPH.
It can be reduced to 0 in a 3-ph machine, with either skewed magnets or skewed laminations.
The cogging in the wind blue is probably not severe.
Anything based on an auto alternator is going to have iron losses, and the losses increase quickly as the iron reaches or passes 1.2 tesla. Under 1 tesla has very little iron loss if the laminates are thin and of good quality iron.
Have you considered a piggy-back alternator for the field supply, running on the same blades?
Would be easier to get the power tracking matched.
G- |
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windymiller
New Member
United Kingdom
60 Posts |
Posted - 26/03/2008 : 17:49:15
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Thanks ghurd for your input...very clear and understandable.
This is where im at......overall the concept of having a piggy back alternator is in my opinion a very good one ,which wouldnt be impossible to make.
The original design with a slave turbine was chosen simply because i thought,this way it would enable the main turbine above start rotating first......quite simply because the field coil would not be energised and thereby let the blades spin with a head start.
When the wind picks up ...the slave turbine gets to rotate and supply power to the field coil in the main turbine....Dont forget at this stage the main turbine should be already spinning pretty fast!!!.
The faster the wind speed ,the better both turbines spin....the faster they spin...the more efficient the main turbine works,and the more power the slave turbine can supply the variable feed.
The downside is calibrating both turbines so as to reach max power per wind speed theyre subjected to.
If it was of the piggy back design ,then i do agree calibratiopn will be easier to sort out...but overall it would be harder for the whole combined "power plant" to start up.
Ive got a variable voltage controller that runs from 0 to 20 volts..3amps max which im going to connect to the main turbine field coil for when the main turbine is ready for testing.
It will be interesting to see how much voltage/current is really needed to stall the turbine in strong wind conditions
Also ive got a laser gadget to check blade rpm.
Still a lot to think and do..but overall im pleased
Good idea about the piggy back though ...maybe others on the forum might what to join in too with your idea.
Im not aware of it being done before so it could be fun.
Help and ideas always appreciated...windymiller
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ghurd
Junior Member
USA
277 Posts |
Posted - 26/03/2008 : 18:54:22
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I see what you are saying about the piggy back and start-up.
Could use a 5.1V (or whatever) Zener to the base of a transistor in the field supply. The piggy back unit would be open circuit until it reached a little over 5V, then it would feed the field coils. Probably need a fat cap on the Zener to keep it a little more stabile.
Even with the field coils directly energized from the piggy back unit, I don't believe there would be a lot of iron losses, and there won't be any drag due to output of the main unit until cut-in RPM is reached.
Then again, at low speeds, the field coils may make it almost like a shorted output for the piggy back unit? I don't know.
It would be interesting to see how much drag increases with the field energized compared to not energized. That would be the iron losses, but it will change some when the whole thing is charging a battery.
G- |
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windymiller
New Member
United Kingdom
60 Posts |
Posted - 26/03/2008 : 23:22:55
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Just a latteral thought....maybe if the whole concept works well,then it may be possible to transfer the the field coil into other types of motors (bigger and stronger)instead of using the car alternator casing :)
We'llhave to wait and see...opens up lots of possibilities for projects
Regards wm |
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MyCattMaxx
Starting Member
USA
9 Posts |
Posted - 27/03/2008 : 02:28:15
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| The only fault I see with that set up is most of us want ALL the power we can get and not waste it to run a field coil. |
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car alternator genny
