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Unread 25-02-2012, 11:14
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Ether Ether is offline
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Re: motor free amps at voltages less than 12

Quote:
Originally Posted by FrankJ View Post
Mabuchi motors web site has a widget that lets you play with different voltages & plots the curves. It looks like they hold the no load current as a constant (independent of voltage) & current line as a constant slope.

go here and play with it.
Excellent reference! Thanks Frank. For anyone who wants to try it, you must first select a motor from their catalog, then click on the motor model to bring up the Javascript applet.

Attached are 12 volt and 6 volt motor curves for an RS-550. As Frank said, the calculations in Mabuchi's applet show Io as independent of voltage, and No proportional to voltage.

I doubt this is strictly true (especially for motors with internal fans), and I realize motor manufacturing tolerances and other considerations (especially but not exclusively motor temperature and wear) make this inquiry an academic exercise, but discussing it brings light to how motors work. STEM.


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