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Re: negative ground conversion

To: Glen <grbyrns@ucdavis.edu>
Subject: Re: negative ground conversion
From: Richard Shipman <mbelect@mindspring.com>
Date: Mon, 08 Nov 1999 20:07:51 -0500
Cc: spridgets@autox.team.net
Reply-to: Richard Shipman <mbelect@mindspring.com>
Sender: owner-spridgets@autox.team.net
Hi Glen,

Interesting question this...

Those small DC motors you remember as a kid had permanent magnets for the
field and you were reversing the armature polarity.

Your starter motor does not have permanent magnets. The field magnetism as
well as the armature magnetism are generated by the electric current from
the battery and since they are both connected to that single cable stud,
they are both reversed simultaneously when you change the polarity. Because
they are both reversed, the net result is as if neither had been reversed,
and the starter rotation remains the same.

Hope that makes sense.

Richard


At 11:10 AM 11/6/99 -0800, you wrote:
>A question to the list,
>
>I've completed the conversion to negative ground as per the excellent
>instructions put forth by Frank Clarici.  Mitsubishi alternator,
>3/8 bolt etc.  All wires joined as directed.  While I wait for
>a new part for my starter, I have time to wonder why the starter
>doesn't run backwards after the conversion.  I remember as a kid that
>the little DC motors in toys all ran backwards when polarity was 
>reversed.  Is this not so with the starter, and if not, WHY?
>
>I realize that if the wiper motor runs backwards it won't make any
>difference in function, but not so for the heater blower and 
>starter motor.
>                       Thanks,
>                       Glen Byrns
>


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