3D Printed Wind Turbine

Tyre kicking at the prospect of 3D printing a Wind Turbine. u/Tubed myself to death. Has anyone considered it? - It seems popular to use old servo motors with a capacitor. But what happened to the idea of using car alternators. If you are learned in such matters and would share your wisdom. I for one would be pleased to enrol as a disciple.

Edited By Rod Ashton on 30/07/2017 15:22:46

They use car alternators on Yachts, using a cast spinner and a long line towed behind the yacht. The alternator is fitted in a plastic bucket to keep it dry, added, you need several spinners as fish (Big) like them.

Wind driven alternators often lose blades due to too high a speed.

Clive

Car alternators are not really appropriate for small wind turbines, as they generate their power at 1,500-10,000 rpm. You would have to gear up your turbine quite a bit to get that sort of speed at the alternator, and there would be power loss associated with that gearing. Small home made turbines tend to use permanent magnet generators. I built a 300w, 5' diameter unit using the motor from a Fisher & Paykel direct-drive washing machine and a design from 'thebackshed.com'. Pretty straightforward Home Engineering stuff, but sadly, no 3D printed parts.

A 3 Phase motor with a new rotor comprising rare earth magnets seems to be the technology of choice, what parts were you thinking of printing and from what material?

- Nick

It is relatively easy to modify car alternators to get useful power at lower RPM (I have a book/leaflet somewhere that I bought years ago, it dealt with using them in simple wind turbines). You can probably find most of the information on the internet these days.

Have you found the Scoraig turbine design? Not really anything better for DIY but just not economic unless you don't have mains at all.

Thanks all. Afraid I keep changing my mind on this according to the reading/viewing that I do, I determine to print the rotors, simple cup units or vertical vane at this moment. But too open minded to begin yet. More delving required.

Thanks Bazyle. That just cost me £17 for Mr. Piggots book. This could get obsessive!!

The efficiency of automotive alternators is pitifully low - less than 50% when warm. Weight is more important than eficiency where vehicles are concerned.

How are you getting on Rod?

I'm tempted to make a vertical vane and mount it on a stepper motor to keep a small battery pack topped up as a 'proof of concept'.

Neil

What about using a bicycle dynamo. They spin a permanent magnet in an iron pole piece with a winding on it. The ac output can be rectified and regulated if required. They are designed to work at relatively low rpm.

Martin C

Neil - I have not progressed too much, as trying to finish the cabinet to do ABS. I have tried a model aircraft motor with encouraging results, so may initially try to drive that. Plus busy making a 4th axis and putting the finishing touches to a spare CNC router that has languished for far too long. Can`t have too many projects??

Martin - Would there be a difference between the old bottle type and a hub dynamo. Interesting gear ratio from a whole wheel?

Rod

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Years [decades!] ago, a friend of mine built a nice little generator around a Sturmey Archer Hub Dynamo.

... I believe there is a modern [ and much more efficient] version available now from Shimano.

MichaelG.

Small/cheap IC engines often run a magneto, I wonder if this could be of any use?

How do you go about regulating speed on a vertical axis turn in case it's blowing a gale outside?

The bottle type of bike dynamo would have a surface speed on the wheel similar to the bike's speed so 5 to 10mph on a wheel about 3/4" diameter would give an idea of operating rpm. They are self limiting in that once the iron core reaches saturation the voltage cannot increase any further. I have never had a hub dynamo to mess about with so do not know what they are like inside but expect a multi-pole magnet rotor to make up for the slower rpm they would be running at. The bottle dynamos have a simple north south magnet. I can't remember what voltage or wattage bulbs were used with them, they have to some extent been superseded by led lighting but I know that they put a noticeable drag on the bike when the lights were on. I just think they are a cheap way of experimenting with wind power. I imagine they will power up a reasonable number of led lights.

Martin C

This is worth a look.

Not convinced about that. Generally, it would simply be the mechanical integrity that would limit the max speed and hence voltage. Go too fast and you will burst the rotor.

The voltage per rpm (Kv) is essentially constant. Magnetic flux is simply a function of V/f (magnetising current, not load current), If you double the speed without a load, you double the voltage but obviously V/f is unchanged. V/f and Kv are a fixed ratio to each other. It's even better if you are running into a fixed voltage - the magnetic flux is lower at higher speeds but you can drive more load current, within the thermal limit of the winding.

Murray

3-phase induction motors can be used directly as generators with no modification. If connected to 3-phase mains and driven above their rated speed they feed power back into the mains. Alternatively they can be used stand-alone with external capacitors to generate 1 or 3 phase supply.

**LINK**

RussB,

I'm sure I read that a vertical wind generater won't overspeed due blade flutter....they did use plastic blades...

not sure about the efficiency of a vertical over a horizontal......ie, 1 blade into the wind and 2 others 1/2 in 1/2 out, that's on a 3 bladed machine...........

had looked into this subject myself but gave up as there was so much conflicting info........spose somebody has done a home build that works and dosen't cost the earth somewhere.........

perhaps I'll look another day.....that's if/when I get some spare time....whatever that is...can't remember.....hahaha....

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