> The real benefit to the brake drum (disk) windmill is just 
> that it costs
> perhaps $150 to build, more or less ..
> The core of the alternator you show surely costs at least 
> $300 (+/-50%)

DIY or one off maybe. But, ...

Under $US25 in modest quantities fully built FOB Taiwan :-)

!!!!!!!!!!!

> The brake drum alternator is also "optimized" to output 
> substantial
> current at 500 RPM or less. You need a lot of magnetic 
> force to do this.
> There hasn't been anything new done to motors in 100 
> years, yes I'm
> trolling, but honestly the only new thing is nicer 
> materials and
> different methods of commutation.

Largely nothing too too new.
Some good stuff can be done with ironless designs due to 
reasonably well priced high flux magnets. But the alternator 
in my picture is largely a common sense combination of old 
technology to produce a highly effective product. Take a 
look at the laminations - standard off the shelf components 
produced in vast volume. You  have probably walked under 
many similar ones over the years as the motors they are used 
in went aboutv their slow and silent business.


        Russell


>> This alternator
>>
>>         http://others.servebeer.com/misc/alternator.jpg

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