# Electrifying a Porsche 944: Changing direction of Warp9 Motor with Kelly controller

**URL:** <https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602>\
**Category:** EV Small Talk\
**Created:** [May 9, 2011, 8:20pm UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602 "2011-05-09T20:20:07Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![blueeagle](https://avatars.discourse-cdn.com/v4/letter/b/e5b9ba/32.png) [@blueeagle](https://community.electricforum.com/u/blueeagle)\
**Post date:** [May 9, 2011, 8:20pm UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602/1 "2011-05-09T20:20:07Z")

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Hello:

I am new in this forum and need some help.  
I am converting a 1986 Porsche 944 into an electric car. I an using a DC motor series wound WarP (9.25 inches in diameter) with a Kelly controller (High Power Opto-Isolated Series Motor Speed Controller with Regen- model HSR14501), operating under a 144 V.

I am able to get the motor run with a foot pedal throttle 0-5V. However, the rotation is in opposite direction: it runs backward in forward gear and it runs forward in reverse gear!. I am bit puzzled, after carefully followed the electrical diagram.  
Any one has encountered this problem before, please give me some tips. Thanks in advance.

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**Author:** ![unique\_electric\_car](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/unique_electric_car/32/5337_2.png) [@unique\_electric\_car](https://community.electricforum.com/u/unique_electric_car)\
**Post date:** [May 11, 2011, 4:09am UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602/2 "2011-05-11T04:09:33Z")

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Hi Blueeagle, If you reverse the field, a DC series wound motor will go backwards. Hope this helps.  
TomSines:D  
[electricevette.com](http://electricevette.com)

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**Author:** ![blueeagle](https://avatars.discourse-cdn.com/v4/letter/b/e5b9ba/32.png) [@blueeagle](https://community.electricforum.com/u/blueeagle)\
**Post date:** [May 16, 2011, 4:14pm UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602/3 "2011-05-16T16:14:59Z")

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[QUOTE=unique electric car;9041]Hi Blueeagle, If you reverse the field, a DC series wound motor will go backwards. Hope this helps.  
TomSines:D  
[electricevette.com](http://electricevette.com)[/QUOTE]

Thank you. But, when I tried reversing the field without the controller, the motor did not reverse. It only runs in one direction.

Unfortunately, in desperation, when I reversed the polarity the battery connection onto the controller, I actually damaged the controller and had to send it for repair.

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**Author:** ![unique\_electric\_car](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/unique_electric_car/32/5337_2.png) [@unique\_electric\_car](https://community.electricforum.com/u/unique_electric_car)\
**Post date:** [May 17, 2011, 3:56am UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602/4 "2011-05-17T03:56:02Z")

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Hi Blueeagle, There are only two parts to a DC motor, the field (stator), and the armature(rotor). The rotor spins, it has two contacts (A1 and A2). The stator is stationary, it has two contacts (S1 and S2), reverse S1 and S2 and the motor must go backwards. Sorry about the controller, but braking stuff is how we learn.  
Tom Sines:D  
[electricevette.com](http://electricevette.com)

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**Author:** ![fany](https://avatars.discourse-cdn.com/v4/letter/f/ecb155/32.png) [@fany](https://community.electricforum.com/u/fany)\
**Post date:** [October 13, 2011, 12:57am UTC](https://community.electricforum.com/t/electrifying-a-porsche-944-changing-direction-of-warp9-motor-with-kelly-controller/1602/5 "2011-10-13T00:57:28Z")

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Yep,Swap S1 and S2 field terminal can change the direction of the motor.  
Needless to say,the polarity of the battery pack must not be [changed.It](http://changed.It) will of course damage the controller.