[AT] Battery in backwards question

[Bill Brueck]

Starters are not sensitive to polarity.  Permanent magnet motors will
reverse with polarity change but a PM motor wouldn't have the kind of torque
we need for an engine starting motor.  Starter motors have field coils so
they reverse field polarity automatically so always turn the intended
direction.  If you want to change direction of a starter motor, rotate the
brushes 90 degrees.  On a few starters it's even possible to misassemble
them this way.  Leads to uncranked engines and cranky customers.

B²

Bill Brueck
   Chatfield, Minnesota, USA

Confusion is a higher state of knowledge than ignorance.
 

-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Larry Goss
Sent: Tuesday, July 22, 2008 11:52 AM
To: Antique tractor email discussion group
Subject: Re: [AT] Battery in backwards question

Battery was in backwards and the starter wtill ran?  Something doesn't sound
right.  Are you sure the tractor hasn't been converted from 6 to 12 volts?

Larry


----- Original Message -----
From: Guy Fay <fayguyma at execpc.com>
Date: Tuesday, July 22, 2008 11:42
Subject: [AT] Battery in backwards question
To: 'Antique tractor email discussion group' <at at lists.antique-tractor.com>

> If a Cub was run for a long period of time with the battery in 
> backwards(negative to ground, Cubs are supposed to be positive
> ground) what will
> likely need repaired? Not charging at the moment.
> 
>  
> 
> Guy
> 
> _______________________________________________
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> 
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