# Newbie 1221C wiring question with A1 A2 S1 S2



## cruisin (Jun 3, 2009)

baboonia said:


> I'm helping a friend hook up a Curtis 1221C controller to a GE motor in a homemade EV. He inherited this EV and the old EVT-15 controller took a dump.
> 
> The Curtis manual example shows the motor with A2 jumpered to S1 (see below)
> 
> ...


The motor manufacturer will have a recommendation on the terminal to be jumped. If using a reverse contactor, you will not use a jumper on the motor. The tranny should NOT be used for reverse.


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## EVfun (Mar 14, 2010)

Leave A2 disconnected in on-road EV applications. The motor jumper should stay as it is currently, switching the connection from A1 to A2 would reverse the motor direction.


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## baboonia (Aug 16, 2008)

EVfun said:


> Leave A2 disconnected in on-road EV applications. The motor jumper should stay as it is currently, switching the connection from A1 to A2 would reverse the motor direction.


Yes, I will leave the motor jumper in place (don't want car going backwards)

Please clarify what you mean. I think you are saying for my setup:

A2 (on controller) goes nowhere?
B+ on controller will go to A2 on Motor (and B+ from battery pack/main contactor)?
M- on controller will go to S2 on Motor?


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## EVfun (Mar 14, 2010)

I've installed 2 Curtis controllers and never connected A2 to anything. You have described the wiring correctly. 

From page 16 of the manual [1]: 


> NOTE: Plug braking is not recommended for on-road electric vehicles. The plug braking feature is intended for material handling and low speed, low load applications only.


I have been told that A2 can be connected to inhibit the sudden braking force that can happen if you roll backwards in a forward gear with the throttle released. It takes several mph for that to happen. I have never connected A2 but if you want to it can be connected to either end of the jumper. You will notice that the Zilla, Soliton, and Netgain controllers lack an A2 connection. You shouldn't roll backwards in a forward gear with those controllers either.

[1] Curtis PMC 1209/1221B/1221C/1231C Motor Controllers, Copyright 1995 Curtis Instruments Inc.


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