It will still move, a motor with magnets will move slower since any EMF
generated will cause a large current (short circuited generator) that
counter-acts the movement, but the reaction is proportional to the speed
of movement, so at slow speed there will hardly be any counter-action
and the vehicle will still roll away, not be held by a short circuited
motor.
NOTE that this is only the case for motors with an active excitation
such
as a PM (Permanent Magnet) motor. Any motor without active field will
not
generate any voltage, so whether shorted or not, so you can turn an ACIM
(AC Induction motor) for example as much as you like, it makes no
difference if it is shorted or not.

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: cwa...@proxim.com Private: http://www.cvandewater.info
Skype: cor_van_de_water Tel: +1 408 383 7626


-----Original Message-----
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Mark Grasser
via EV
Sent: Friday, June 20, 2014 5:36 PM
To: 'Gary Krysztopik'; 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] winter parking brake

Help me here. I thought that if you shorted across the motor cables it
would
not move, no?
Mark Grasser

"as well as the parking pawl that drops into the teeth on the flywheel
IIRC"

The MES drive has an output to activate a parking pawl when in
electronic
"park".  I never implemented it but I thought it was a great idea.


On Fri, Jun 20, 2014 at 9:47 AM, John Lussmyer via EV
<ev@lists.evdl.org>
wrote:

> Probably Wheel Chocks would be the next choice.
>
> On Fri Jun 20 08:37:37 PDT 2014 ev@lists.evdl.org said:
> >I searched but didn't find a similar question.  If one exists and I
> missed it
> >please redirect me.
> >
> >My question concerns manual transmissions and parking in the winter.

> >We don't use a parking brake in the winter here since the pads and 
> >shoes
> freeze
> >to metal parts.  With no engine compression to hold the vehicle what 
> >have others done?
>
>
> --
>
> Worlds only All Electric F-250 truck!
> http://john.casadelgato.com/Electric-Vehicles/1995-Ford-F-250
>
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