I believe that what is being missed here is that for many years we have
become used to DC motors that have permanent magnet fields. The
improvements in magnetic material has made this possible. However in the
days of 'our' cars the magnets were not good enough and a wound field
winding was used.
Changing either the field magnetism OR the armature connections would
reverse the motor. With a permanent magnet motor changing the
connections does reverse the motor. On a motor with a wound field coil
changing connections over externally has no effect because BOTH the
field and armature get changed and the motor still spins the same way.
You have to get inside to change the rotation of a wound field motor.
Regards
>If you switch polarity, it does not affect the heater motor spin direction.
>
>On 7/15/10, Richard Ewald <richard.ewald@gmail.com> wrote:
>> Are you sure about changing the polarity not changing the direction of
>> rotation? As I recall it does.
>> It won't help if the case is grounded, but if the case is not grounded, you
>> should be good to go.
>> Rick
>>
>> On Wed, Jul 14, 2010 at 9:20 PM, Alan Seigrist <healey.nut@gmail.com> wrote:
>>
--
John Harper
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