Build my own cheap DIY wind generator - possible?

[john]

Saw this on ebay:

http://www.ebay.co.uk/itm/WIND-ENER...trial_Tools_Generators_ET&hash=item4d1b52185c

costs with postage around £34, and wondered if I could build a cheap DIY wind generator for the boat. I'm thinking I would need:

Cabling
Regulator
Blades (ideally I'd like a vertical generator)
Waterproof housing and fixing bracket.
Cut out device for when the wind blows too hard

I'm handy with wood and epoxy, so blades and housing shouldn't be a problem.

This is what it says about the generator motor:
Generator Measurements Without Shaft
Diameter: 45 mm
Height: 80,5 mm
Shaft Measurements
pinion gear: 15 mm
Circumference: 12 mm

Technical Data

Ratet speed at 12V ->10.700rpm
(For getting high speeds you must use a transmission)
Maximum output power -> over 450W
Maximum torque 425 mNm

Current draw open circuit: 3.5 Amps, and full load: 75.8 Amps

The Generator is NEW and fully functional.

Ideal for 12 volt purposes; allows an LED light with 20 LEDs to shine brightly (LEDs in parallel) and more!

What have I missed?

John

 

[duncan99210]

Nothing except that you'll need a gearbox as well to bring the revs up to the required 10,700 rpm. That'd add to your costs, as it would require a robust housing so that you can mount the gearbox, generator and blades. Might be simpler to look at one of the Chinese wind turbine which go for about £350.

 

[jimmcgee]

find yourself an old printer , pull the stepper motor out , cheep generator :encouragement:

 

[CAPTAIN FANTASTIC]

By the time you have finished the project it would have costed you a lot of money, time, effort and you would have a generator of questionable quality. You will be better off buying a new wind generator which nowadays are very cheat on the internet.

 

[Rigger Mortice]

It's just an electric motor. Nothing wrong with that as any (most?) DC motors will produce electricity if you attach some form of drive. Whether it does so efficiently or not is another matter. What wind speed you will need to get it running is also unknown. How it would stand up to a marine environment running 24/7 is another unknown.

The main specification figures they have given are probably for its performance as an electric motor. However if, as a generator, it lights up 20 leds in parallel then it would be producing something like half an amp probably at around three volts. Not much help on a boat.

It could be interesting to play around with but you could get a similar electric motor for a lot less than £34.

FWIW I quite fancy having a go at making my own turbine. It's another project on my wish list.

 

[pampas]

Have made several, even one based on the Forden model, all worked3 never put out move than 300 Ma, The biggest problem is findin a permanent mag motor the gives takes 300 rpm around 60 rev/min. The used to be in the1950`s a horseshoe motor sold by Gamages for model power boats, ideal for say a tug.

The ones I made used a Dynahub from old Raleigh bikes, taken to pieces, windings rewound in a slightly bigger gauge and more turns on two I had to make a new shaft, case hardened and the ball cups ground to size, lot of work and not much reward except "I Made It"

Basically you will have to drive the motor at twice its rated rpm range ,in order to get anywhere near the loading required when used as a motor. Best of luck with your efforts.
Gordon

 

[AntarcticPilot]

Nothing except that you'll need a gearbox as well to bring the revs up to the required 10,700 rpm. That'd add to your costs, as it would require a robust housing so that you can mount the gearbox, generator and blades. Might be simpler to look at one of the Chinese wind turbine which go for about £350.

Efficient, quiet turbines aren't simple, either! But the gearbox requirement is a real problem for DIY, again requiring quiet operation, extremely robust construction, and probably some sort of fail-safe for when the next lot of gale-force winds hit us.

 

[john]

OK, opinion seems to be to buy a cheap Chinese model, but thanks for gently deflating my enthusiasm with a dose of financial and practical reality. Can you really get a generator from the innards of a printer?

 

[William_H]

Alternators

You can use a brush type permanent magnetic electric motor as a generator. However the motor must be spun quite fast to generate power. If you could get something like a 24v motor then it may generate enough voltage 14+ to charge a 12v battery at reasonable revs.
Inevitably to extract real power from a turbine then you need a large area (diameter turbine) which then inevitably must turn slowly because of the tip speeds as related to wind speed. So inevitably you will need a gear box or similar speed increase like a belt drive.

An alternator as from a car has many advantages. it uses current to provide the magnetic field for generation. This can be more powerful than a permanent magnet and is easily controlled to regulate output. However it does represent a waste of current especially at low or nil wind situations. The alternator also has the advantage that the output current comes out as 3 phases so more efficient or less copper reistance loss and no brushes to bring out the generated current. (still usually needs brushes to cary in the low field current.)

An interesting design used on bigger alternators is the brushless design. Here a second smaller alternator sits on the end of the shaft. The rotor amkes current from rotating in a magnetic field provided by a coil on the outside fixed part of the body. The rotor generates AC which is rectified by diodes in the rotating part and connects the current to the larger rotating field coil like an ordinary alternator. You vary the current of the small field coils on the outside which varies the power generating of the small alternator which makes current for the field coil of the main alternator. So no brushes. (obviously no brushes in a permananet magnet alternator but no control either.)

Interesting the mention of Chinese wind turbine generators. My friend bought one for a remote cotteger power supply. Very disappointing. The pernanent magnet I think lost a lot of flux which meant that it did not generate enough voltage at normal wind speeds to charge a battery. It had a box which the blurb might indicate had a regulator in it. In fact it only contained 3 phase bridge rectifier. (6 silicon diodes). I managed to improve charging by fitting 6 schotke diodes which did improve charge a little. But from a claimed 600w capability it delivers about 5 wattys in say 12 knots of breeze.
I am tempted to recommend Op buy a 24 v Chinese turbine and use it to charge 12v battery. Like a solar panel I think any excess voltage generated will dissipate in the internal resistance of the windings and it should give charge at reasonable wind speeds. good luck olewill

 

[cimo]

I'm a big fan of Hugh Piggott and the good work hes been doing down thru the years.

His permanent magnet generator plans are very detailed and make good reading if nothing else.

I've been meaning to build a reduced scale machine based on his blueprint for some time now (once I have free time again perhaps).

worth a look - http://www.scoraigwind.com/

 

[jimmcgee]

Can you really get a generator from the innards of a printer?

yes , so get yourself down to the local skips or car boot sale :encouragement:

 

[paul-essex]

how fast would you need to turn a car alternator ? and could a solar panel could supply the field current so no battery drain if no wind

 

[KellysEye]

>Ratet speed at 12V ->10.700rpm

Are you sure an Ampair for example is 500 -1400 rpm, !0,000 rpm is a formula one engine. If it really is that I would walk away it doesn't feel right.

 

[AntarcticPilot]

>Ratet speed at 12V ->10.700rpm

Are you sure an Ampair for example is 500 -1400 rpm, !0,000 rpm is a formula one engine. If it really is that I would walk away it doesn't feel right.

The necessary speed varies with the type of generator; the 10,700 rpm is the speed quoted for the generator unit the OP specified. However, Alternators are usually driven at several times the RPM of the engine; not exactly sure on my Volvo 2003, but it looks like about 3:1 gearing - which mean that when the engine is doing a perfectly normal 2000 rpm, the alternator is doing 6,000 rpm; I'd imagine it tops out at around 7,500 rpm. My car engine normally runs at 3,000 rpm or more (and it's a high efficiency 800cc engine!) so the alternator on that may well be doing in the region of 10,000 rpm and a lot more when on the motorway!

The point is that for efficient generation, you need high rpms; the Ampair or whatever will certainly have gearing to increase the RPM of the turbine to something much higher for the generator.

 

[Gwylan]

You can make one out of cabbage leaves and a 3d printer, but most of us realise that the overall efficiency is not going to make the cut. Also we do not have enough time left to justify squandering this much time on a non delivering project.

Get a solar panel and move on.....

 

[William_H]

Quite so Gwylam solar is the easiest cheapest most convenient way to keep batteries charged. However this is a discussion thread probably in most cases removed from any actual practical project. Nevertheless some may just have the urge to try building one.
With any generator the voltage produced depends on the speed of rotation the magnetic flux of the field magnetic source and the number of turns on the pick up coils. Now speed of rotation is a bit misleading it is actually the speed of magnetic lines of force cutting the pick up wire so multiple North and South pole ends can multiply the speed of lines cutting the wire so voltage. A typical vehicle alternator has 6 pole pieces 3N and 3 S as extensions of the field coil.
One of the real difficulties in designing a wind powered gen is the huge range of rotation speed we need to get useful work from. Typically a ratio of about 10 to 1. So if we provide enough turns on our pick up coils (stator usually) to get 15v DC at 5 knots of wind then at 40 knots of wind we will produce 120v DC which must be wasted somewhere to suit the 14v charging that we want. A tapped stator coil with a switch might be beneficial ie lots of turns for low wind speed and select fewer turns for higher wind speed.
An MPPT type regulator would probably work admirably to convert the variables of gen output to that needed for battery charging. Or we can use a DC supplied field coil to vary the voltage by varying the magnetic flux. As we do in our car.
Incidentally solar power to the field coil is one idea but would mean no charge with no sun. It would however not be so difficult to buid a rotation detector to switch on field current from the battery when rotation of useful speed is detected.
All just cogitation. My boat is far too small to fit a wind gen and solar works well. The neighbours and council would never let me mount a wind turbine at home so again solar does the job. But if I had a farm I would mount one. good luck olewill

 

[OldBawley]

I have made one also and are very pleased with the result. It loads at low wind speeds, there is a tread about it at :

http://www.fieldlines.com/index.php/topic,147282.msg1016517.html#msg1016517

 

[charles_reed]

Looking at the Rutland 914i output, I was struck by how pathetically low it was compared to my solar panel array.

Unless you're in a very windy, sunless area (sounds like Spitzbergen, in winter), for most of us boaters, wind-power is a non-starter.
I know that Germany has boosted Denmark's GDP over the last 12 years by its investment in wind-farms - but I suspect that they still find their LNG booster stations essential.
Hence their feelings of acute crotch discomfort over Putin and sanctions on Russia.
Before anyone else feels they have to say it - the Brits are against any attempts (probably more than the Germans) to punish Russia for its return to revanchist imperialism, we're too much in love with all those Russian oligarchs and all the lovely money they've squirrelled away outside their country, before their countrymen catch them with their paws in the cookie-jar.

 

[Rigger Mortice]

I have made one also and are very pleased with the result. It loads at low wind speeds, there is a tread about it at :

http://www.fieldlines.com/index.php/topic,147282.msg1016517.html#msg1016517

I like your approach to it all!

Anymore information on the Ametek motor that you used?

 

[john]

I have made one also and are very pleased with the result. It loads at low wind speeds, there is a tread about it at :

http://www.fieldlines.com/index.php/topic,147282.msg1016517.html#msg1016517

I admire your ingenuity!