Neodymium magnets

[Etownlax]

Any Help here with the above questions?
Thanks,
-Randy

[nebbian]

[Etownlax]

Hey,

Thanks for the Info nebbian.

I don't know anything about car alternators, but I do believe you must have a fairly high speed(atleast higher than average windturbine). You could always gear it up, but you have losses in gearing it up and that might make it even below that of a PM generator.

So having a capacitor in parallel with the coil will make the voltage go up? Is that only under load or is that all the time no matter what?

Thanks again for the help, best wishes,
-Randy

[Bob Boyce]

When efficiencies of alternators are calculated, they almost never include the power drawn by the fields coils, as that is considered part of the voltage regulation. By the time you calculate field/regulation power costs, the efficiency of an average automotive alternator drops into the 55% - 60% range. Shunt wound or series wound motors also suffer from field winding energy cost losses.

When comparing an automotive alternator to a bicycle generator, sure, no comparison. Bicycle generators are of cheap manufacture, with poor quality magnets and other cheap componentry. They are not designed for longevity, and are too low of a power capacity to be of any use. I would be suprised if you get 60% efficiency out of one.

To do a real comparison, compare an automotive alternator to a Lynch type PM motor/generator of similar size, like the Briggs & Stratton Etek. They are so much closer in scale for power level and size. 90%+ peak efficiency, with the average better than 85%. We don't need to be stuck with the poor efficiency of archaic magnets or electromagnets (field coils) when there are supermagnets available.

The poor reputation of PM motors/generators is due to the limited RPM range where efficiency is highest. The Lynch motor (pancake design) did away with that limitation, and made use of the modern supermagnets.

Bob

[kumaran]

Hi Guys,

If talking about efficient generator, how about Muller Generator design? Magnets and stators are odd/even design to reduce cogging. I'm not sure if it is suitable for wind generator. Below are links to my MullerGen photos which I was experimenting.

Magnets
http://www.myfilehut.com/userfiles/1329 ... agnets.jpg

Neodymium magnets (grade forty eight). Size 25mm x 10mm.

Rotor
http://www.myfilehut.com/userfiles/1329 ... _empty.jpg
http://www.myfilehut.com/userfiles/1329 ... _layer.jpg
http://www.myfilehut.com/userfiles/1329 ... _layer.jpg

Each side of the rotor have 20 holes to fit magnets. Total of 40 magnets can be placed in front and back of the rotor.

Stator
http://www.myfilehut.com/userfiles/1329 ... tator1.jpg
http://www.myfilehut.com/userfiles/1329 ... tator2.jpg
http://www.myfilehut.com/userfiles/1329 ... tator3.jpg
http://www.myfilehut.com/userfiles/1329 ... or_gap.jpg
http://www.myfilehut.com/userfiles/1329 ... rminal.jpg
http://www.myfilehut.com/userfiles/1329 ... il_pin.jpg
http://www.myfilehut.com/userfiles/1329 ... l_pin2.jpg

I can arrange the stators to generate 3PH or 9PH. Above pictures are my test stator coils and stator holder made with nylon. I'm not sure how many stator coils I have made for testing. Each gave different results.

Generator
http://www.myfilehut.com/userfiles/1329 ... m_gen1.jpg

Used 3PH motor (run in RV mode using 1PH power supply) to test the generator. The generator is very heavy and spun till 3000 rpm with my fingers crossed on each test run.


I hope this helps.

[Etownlax]

[kumaran]

Hi Randy,

By theory Muller Generator should work with great efficiency. With the RVMullerGen setup, I manage to get 1:1 (input vs output). Both prime mover and generator works at 100% efficient. In fact the output is slightly more compared to input. I have to stop the project because of financial issue. Too much money need to spend for changing sets of parameter.

For wind generator I find is still the best. Complete with step by step information on building wind generator from ground up. Do you have any previous experience in making wind generator?

[Etownlax]