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Date: Wed, 25 May 2005 08:29:58 -0600
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
From: Bill Dube <bdube@al.noaa.gov>
Subject: Re: [FlyRotary] Alternate alternator
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>
>I went further and started searching for a good candidate for the 
>motor.  There is a bunch of electric scooter motors on Ebay selling for 
>less that $10 each.  For example:
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=75210&item=7157958719&rd=1
>
>These are 24V and rated for 2500 RPM.  The voltage is wrong and the speed 
>rating is a little low.  There are some rated at 2750RPM, but I'd like to 
>see 3000.  16A is plenty for a backup generator.
>
>Bill, what do you think?  Could you suggest a better candidate motor.

         I would stay away from the inexpensive brush motors. They really 
don't last unless they are high-quality. You want the back-up to work when 
you need it.

         Small brushless DC motor/generators are out there, typically in 
scooters. They are typically set up for 24 volt input power, but I suspect 
they would happily put out 12 volts with modification to the controller (or 
complete substitution of the controller for a simple regulator.)

Here is an example:

http://store.nycewheels.com/go-motorboard-transporter-1500-electric-scooter.html

         You can likely buy the motors for some fraction of the cost of the 
scooter.