[Healeys] Heater motor

John Harper ah at jharper.demon.co.uk
Thu Jul 15 02:30:44 MDT 2010


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 at 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 at gmail.com> wrote:
>>

-- 
John Harper


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