# Curtis 1221C



## Guest (Apr 13, 2012)

I have a controller similar to the Curtis 1221C that I am trying to get running. I had some weird stuff happen yesterday when I had it connected to an old 3 wire pot to a two wire connection. I have it on video on my blog. However today I connected up a known good potentiometer that is a two wire one to the controller and got absolutely nothing. I have the main connections to the motor and pack connected properly and the Curtis from what I can tell uses traction pack voltage to power the controller internals. I also tried with only 12 volts from the Aux battery and got nothing. Is there something I am missing? There is one wire to the pack positive then two wires for the potentiometer which is the 2 wire PB-6 style potentiometer. Im not getting any thing and there is no external visual to indicate a problem. Since it did some weird stuff yesterday I figured it was just because it was a bad potentiometer which it was. Since replaced and tested with the Large Kelly controller I assumed it would work. You can see the video on my blog here: http://onegreenev.blogspot.com/

Scroll down to Further Progress section. Posted yesterday. It could be that the throttle section in the controller is bad as well.


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## Ziggythewiz (May 16, 2010)

Some controllers do 0-5k and others 5k-0. It looks like when you connect the pot it may be reading a pedal down condition, so it waits until you throttle up, which it sees as down, then it releases the safety so when you release the throttle it throttles up.

Why not hook up a multimeter so you know what the pot is doing instead of trying the different wires?

Also, you might consider a manual switch in the ignition loop, so you can turn things on without walking around the car and out of sight.


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## Guest (Apr 13, 2012)

You know I never thought of that. An easy enough thing to fix. Just reverse the connections which I can do for a test but can't imagine it will help. I will test it to be sure and post the results. 

I did try with the pot starting on either end of the swing when starting out. I did install the pot into the case but removed the spring to allow setting the pot to either end then restarting to reset the controller thinking that might help but I did not reverse the wiring. Still don't think that will help. 

Pete


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## EVfun (Mar 14, 2010)

Is there a chance that either of the 2 pot terminals have ever seen pack voltage? That kills a Curtis controller. The third small terminal is ksi and should be hooked to traction pack positive. That means there is a pack positive connection very close to a couple of terminals that can never see pack voltage. More than one Cursit has been damaged this way.


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## Guest (Apr 13, 2012)

I'd be hard pressed to say yes but I guess it's possible. Cables were shrink wrapped well and there is an actual plug. It is possible it was wired wron before being sent. Did you see the flick on my blog showing what it did with the bad pot?

Pete 

If not, go have a look.


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## EVfun (Mar 14, 2010)

I found Curtis mentioned in the "Beta Again" entry but I don't see any video linked to that blog entry. I didn't find any other mention of Curtis on you blog home page.


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## Guest (Apr 14, 2012)

EVfun said:


> I found Curtis mentioned in the "Beta Again" entry but I don't see any video linked to that blog entry. I didn't find any other mention of Curtis on you blog home page.


It was actually one down from that but here you go.


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## Guest (Apr 14, 2012)

The pack voltage did not touch. I actually got it to run this afternoon. I took the old PB-6 and it worked. The pot was very very very sensitive but it did work. I am processing a little 8 minute flick right now. It will be up tomorrow. What I am thinking is that I have two kinds of potentiometers. One for resistive and the other for voltage. One works on one controller and not the other and vice versa. It is strange but that is what I found. I found that both series controllers got too hot to handle within 10 minutes of no load running. I am thinking it is because I am shunting the one motor and running a series controller when I should not be doing that with such high voltage. 

Something is causing the controllers to overheat fast under no load. I never experienced it with a series motor under no load but running for a bit. I asked Major a question about running the motor as I have it setup. It works but only for a very short time. 

Pete 

Todays movie will be up tomorrow. I did install the SepEx Kelly again and Kelly controller said the controller needs full pack voltage for power to the controller. So it has full pack voltage fused at 2 amps. I need to install the other pot from Evnetics because it works for testing to see if my issue with that controller was only a voltage issue to the controller. I only used 12 volts. They want me to use 72 volts. So I did. Every thing looks fine except I did not have time to connect the throttle for testing before it got dark. 

Pete


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## Guest (Apr 14, 2012)

EVfun said:


> I found Curtis mentioned in the "Beta Again" entry but I don't see any video linked to that blog entry. I didn't find any other mention of Curtis on you blog home page.


It is more like a Curtis Clone. It is not a real Curtis.


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## Guest (Apr 18, 2012)

Curtis Clone is no longer overheating. It was the field connected up to the wrong terminal. With all my testing today it never even got warm. I remained fully cool to the touch and I do not have a heat sink installed. I am well pleased and will be doing a short road test tomorrow.


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