# homemade alternator from microwave parts

Discussion in 'The Projects Forum' started by DaTowd, Mar 11, 2016.

1. ### DaTowd Thread Starter New Member

Jan 3, 2015
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0
Hi Gang,
I have a idea on building a large permanent magnet alternator. For a vertical axis wind mill
Using microwave magnets and transformers.
I saw a write up from a guy in Scotland that built his wind charger from rare earth magnets and home coiled wires.
My question: building the rotor with 12 or more rare earth magnets on a Volvo 240 front wheel strut and bearings and using the transformers as the stator,built in a circle and wired together( which will be one part I'll need help on ).
When the magnets pass each transformer AC current should be made. Correct?
No idea on how to regulate it - I might use it to heat water in a large stainless steel milk tank and using a heat exchanger into the shop.
thanks
Hank

2. ### #12 Expert

Nov 30, 2010
16,031
6,540
Bit of a delay here just to sort thoughts. Every energy conversion has an efficiency less than 100%. If you just want to heat water, it's more efficient to just place a paddle in the tank. Electricity is much more versatile than just heating water. That's the main reason to convert to electricity first and heat second. You can use the electricity for other things.

As for regulating? Neither of us has a clue about how much electricity you're going to get. Hook it up and see what happens. After we know some measurements, we will have something to work with.

3. ### tcmtech Well-Known Member

Nov 4, 2013
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A few basic calculations on electrical power to heating BTU's should pull your ideas into reality real quick.

1 watt is 3.412 BTU's. Go from there and you will quickly find that if you want to heat anything big building a solid fuel burning furnace is way cheaper and more realistic.

4. ### Alec_t AAC Fanatic!

Sep 17, 2013
5,590
1,070
You would have to dismantle a MOT to make it useful as a stator coil, since the MOT magnetic core is a closed loop, usually with a few welds holding laminations in place.

5. ### shortbus AAC Fanatic!

Sep 30, 2009
3,951
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How are you going to get the square/rectangular MOT to work with a round rotating magnetic rotor? Your better of finding an electric motor and modifying its rotor by adding magnets to it.

6. ### tcmtech Well-Known Member

Nov 4, 2013
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The DIY roll your own generator/alternator crowd has always entertained me.

Everyone I have ever met says its about cost and efficiency yet by the time they have made anything that passes for a half assed semi functional marginally efficient design that doesn't break down every 100 or so running hours they could have searched for and bought a good used commercial/industrial application servo motor or permanent magnet three phase motor or converted a good sized commercial truck alternator over to a DIY PM rotor and been ahead of the game on every aspect.

Seriously a off the shelf 24 volt 100 amp commercial truck alternator converted to PM rotor being driven by a serpentine belt with a bicycle hub and rim for the drive pulley behind the blades can easily make more electrical power (1 - 2+ KW if the blades are big enough) than any DIY hack job design of similar size and weight.

7. ### wayneh Expert

Sep 9, 2010
11,920
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I spent (wasted?) some time playing around with a novel design for an alternator for windmills. It had some merit at small scale but I eventually decided small windmills are a waste of time and capital. There are enormous benefits of scale in a windmill.

I also had the realization that commercially constructed alternators are darned efficient in terms of weight, volume and cost, even if you have to rebuild one for lower rpm. Building your own is tough. Machining tolerance, which limits your air gap, is a big factor.

#12 likes this.
8. ### tcmtech Well-Known Member

Nov 4, 2013
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Yea but every DIYer knows they can make one out of old brake rotors, plywood, PVC pipe, bits of copper wire, old microwave oven parts, ancient speaker magnets, some zip ties and glue that's going to be at least 98% efficient and put out at least 2 Kw at less than 100 RPM (on a 6' dia PVC sewer pipe blade set no less) all for under \$100 that will last for at least 100 years between servicing.

9. ### DaTowd Thread Starter New Member

Jan 3, 2015
6
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Thanks for all the spiritual advice .
Like I said just an Idea
you guys make many good points
What does MOT mean?
tcmtech your last post was like you were looking at my drawing board
cheers
Hank

10. ### #12 Expert

Nov 30, 2010
16,031
6,540
Microwave Oven Transformer.

Jan 3, 2015
6
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thanks
Hank

12. ### tcmtech Well-Known Member

Nov 4, 2013
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It's not like the concept and list of materials used is new to the internet.

13. ### Sensacell Well-Known Member

Jun 19, 2012
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...And the Oil Companies have been suppressing the technology for years, along with those carburetor designs that make your old V8 get 72 MPG with the air conditioner running...