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gotwind
Forum Admin
United Kingdom
754 Posts |
Posted - 16/09/2007 : 16:46:44
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I'm guessing the £47(motor)would have the strong Neodymium magnets fitted already like the more expensive generator ones they sell for 3 times the price, I can't imagine they would have had ceramic magnets specially made aswell.
The extra cogging(i.e the 'lumpiness' when rotating the hub by hand - like the dynohub)may be from an Iron core on the stator, that maybe the generators don't have.
This would be very difficult to remedy, we'll have to wait and see...
Ben.
The Futures Green - Getwind of it. |
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BushWhacker
Junior Member
Canada
254 Posts |
 Posted - 16/09/2007 : 18:11:07
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OOOPS! I forgot to mention that most of the hubs I looked at were 3ph AC with a fair bit of cogging, and had the poor regenerative properties.
I think it will be easier to deal with a DC unit and change the brushes every now and then.
As for finding them used... I don't think I'll live that long.
Here are the 36 Volt 400 Watt hub dimensions...
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
Edited by - BushWhacker on 16/09/2007 22:10:24 |
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windymiller
New Member
United Kingdom
53 Posts |
Posted - 17/09/2007 : 09:20:08
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Hi everyone...I see one of you have bought one of the stepper motors!.
I see ben has took the trouble to enquire about its suitability as a wind generator.I must admit on the surface they do look identical to the motors he sells as wind turbine generators.
There are ways of "reducing" the cogging issue by making alteraions with the permanent magnets im sure theres info on the web about this...im sure it can be reduced to an acceptable level.,
Ill be interested to know what the differences are beween the two set ups.
I beleive one of the ways cogging can be reduced is by using a method called "scewing",which reduces cogging considerably ,to the point of not being noticeable.This is not something we can do ourselves( i dont think )its a design feature of the components inside the motor.
Still think it could be a good option as power source for the money....cogging or no cogging it could be easy to sort out!..bargain cheers windymiller. |
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frankineto
Starting Member
United Kingdom
17 Posts |
Posted - 17/09/2007 : 10:04:12
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looked at different options to min---- the cogging effect .
spent the whole of sunday looking through all the different methods - so much information and so little time .
scewing is one option and it seems that the motor can be taken apart .
running some magnets on the outside was another option
'bumping ' was another option which involved sending a small charge to the motor from the battery to kick start it so that the cogging was minimised .
before i do anything , the motor still has to arrive so hopefully put some pics up sometime this week.
wiring the motor will be a challenge so any help there would be gratfully appreciated.
have a good week all
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gotwind
Forum Admin
United Kingdom
754 Posts |
Posted - 17/09/2007 : 10:38:46
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Here is the companies web site, based in the South East of Scotland, I see no mention of a Brushless stepper motor!
http://www.renewablecomponents.com/
The Futures Green - Getwind of it. |
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fungus
Junior Member
242 Posts |
Posted - 17/09/2007 : 11:07:49
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| Maybe he buys in stepper motors and modifies/rewires them? Seems like it. He's only about ahalf hour to hour drive away from here, could visit and have a look.... |
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fungus
Junior Member
242 Posts |
Posted - 17/09/2007 : 11:10:07
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Oh, and about cogging;
It's caused by alignment of iron 'teeth' which hold the coils, as a magnet goes over the gap between them it wants to stay on the last tooth, when it gets over that then it is then attracted to the next tooth. Clever ways such as offsetting the magnets or skewing them at an angle can almost completly get rid of the effect. |
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gotwind
Forum Admin
United Kingdom
754 Posts |
Posted - 17/09/2007 : 13:03:19
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Hey Fungus, I'm not sure what your career plans are, but if renewablecomponents are close to your home, it might be worth making yourself known to them - You never know...
Note:
I would like a few free shares in the company when you become the MD 
The Futures Green - Getwind of it. |
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fungus
Junior Member
242 Posts |
Posted - 17/09/2007 : 17:02:26
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Ok,
I went over there earlier and purchased one of the motors; got it for £35, they said without postage? It is very stiff, hardly any cogging though. They are supposed to have a 6' blade set on them, the actual generators were made for them; the actual company is just a plastics manufacturer. Shorting the wires its virtually impossible to turn the shaft at more than about 2 rpm :) |
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gotwind
Forum Admin
United Kingdom
754 Posts |
Posted - 17/09/2007 : 17:19:48
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Well done fungus.
I assume it was the smaller 1000w motor you bought?
I wonder where the 'stiffness' comes from (keep it clean Ben)if not from cogging?
Do you think the motor could be modified in some way Fungus to maybe accept a set of PVC blades?
£35 was a very good price, if it can be utilised as a wind generator.
Cheers
Ben.
The Futures Green - Getwind of it. |
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fungus
Junior Member
242 Posts |
Posted - 17/09/2007 : 17:36:52
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I think the stiffness will be from a very tight airgap, this could lead to losses in the iron...
Just talking to someone and he thinks that they do look similar to industrial servos, odd how theres a different 'version' for the wind gens...
Testing on one phase, I can light up a 23w light bulb by hand to full brightness at pretty low speed, but its pretty hard to spin it fast. To be honest, all the parts would cost a lot more if you bought them individually (magnets, one inch shaft, bearings, case, holders, laminations, copper......) |
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frankineto
Starting Member
United Kingdom
17 Posts |
Posted - 17/09/2007 : 19:25:15
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well , we both in the same boat . mine arriving tomorrow so i will be looking at geting this thing decogged .
i wonder if placing some magnets on the front would minimise some or all the cogging .
have a look at this link for some idea
http://www.fieldlines.com/story/2007/3/9/2533/99152 |
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BushWhacker
Junior Member
Canada
254 Posts |
Posted - 17/09/2007 : 19:27:01
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Hi Fungus,
Great score on the motor! I wish I had such good luck at finding products.
One thing you might want to try to reduce the stiffness (e-gads! This is starting to sound like a porn site.) Is by using Tri-Flow http://tinyurl.com/2n89w to lube the bearings. I have been using Tri-Flow for over 25 years on bearings (ball and plain), rifle bolts, and trigger groups/workings, and any other thing where you have metal on metal contact points that need lubrication. This stuff lubes like magic!
I would however suggest that you find a way to spin the motor over (rigged up to a drill perhaps? and charge up a battery while you do it) ten thousand revolutions or so to get the initial break in on the bearings because if you use Tri-Flow before that the bearings will take forever to break/wear in.
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
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frankineto
Starting Member
United Kingdom
17 Posts |
 Posted - 17/09/2007 : 19:33:36
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| hmmmmm lube and motors - must beat the cheap stuff |
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BushWhacker
Junior Member
Canada
254 Posts |
Posted - 17/09/2007 : 20:47:15
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Frankineto, Tri-Flow contains Teflon that works its way into the microscopic pores of the metal it is lubricating. The Teflon on Teflon friction is far less than a petroleum based lubricant.
This is a really slick (sad pun intended,*insert groan here*) product.
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
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Topic |
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Interesting new source of possible wind generators
