# Curtis 1231c controller



## albano (Jan 12, 2009)

Hi to all,

Can i put on a by-pass contact on a Curtis 1231 controller at 144 volts?


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## Qer (May 7, 2008)

Generally speaking this is a bad idea. I would advice against a bypass contactor since it can weld shut and therefore be impossible to disengage again.

For your own safety, consider a stronger controller instead.


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## albano (Jan 12, 2009)

Qer said:


> Generally speaking this is a bad idea. I would advice against a bypass contactor since it can weld shut and therefore be impossible to disengage again.
> 
> For your own safety, consider a stronger controller instead.


Yes i know it a bad idea. 
The problem is we having a dyno day on Saturday and it will be the first electric on the dyno. My aim is to show everyone the torque electric has.

I do have an emergency cut off to switch off the battery in case the contactor stuck. 

Has for my drag bike I have to wait for the strongest controller, I want the controller to handle maximum volts and maximum amps. Hope for *Soliton1* and i want it soon.


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## Qer (May 7, 2008)

Well, you'll get torque all right, but the problem is that you won't know beforehand how much. The internal resistance in a DC-motor is some mOhm and the resistance in the battery pack is also a fraction of an Ohm so when you activate the contactor you're more or less short circuit the electric propulsion.

Unless you're not already driving full speed your motor will probably jump directly into the 4-digit current area, quite possibly with a pretty nasty first digit and SOMETHING will break. If you're lucky the fuse will blow, if you're not quite as lucky the shaft on the motor will snap or the batteries will blow up. Literally.

Even at full speed this is a bad idea, at a full stop it's a catastrophic idea.

But hey, you'll probably make it to the head lines at least...


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## dimitri (May 16, 2008)

I guess if he controls the bypass contactor via some "Boost" push button and it only holds while he has the button pressed, and he only presses it once EV is running, motor has decent RPM and BEMF built up, then it should work as expected. Just make sure no one presses the "Boost" button while standing still 

reminds me of a scene in first "Men in Black", "DO NOT, I REPEAT, DO NOT TOUCH THAT RED BUTTON"


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## albano (Jan 12, 2009)

HI all,

Here is the dyno graph from the dyno with 1231c controller and 11" Toyota forklift motor. The batteries are old And i DID NOT HAD BY-PASS. Still need to find out how to improve RPM. This was my first time and the project was done in 1month.

Albano


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