# Cannibalizing a sepex controller



## DavidDymaxion (Dec 1, 2008)

Is it a Curtis? A Curtis Sepex is very programmable, you might be able to program a motor map that gives the field 0 Amps. Another option might be to program the field for minimum possible Amps and put a light bulb across the field terminals (it would waste a little bit of power that way, but not much). You can go to the Curtis website and download the manual.

Please post what you figure out, that knowledge might be useful to me. I'll post if I figure something slick out, too. I have a Curtis Sepex but I want way more power than it can deliver.


xtian999 said:


> Can someone tell me if it is possible to use the power side of a GEM sepex controller to run a series motor? Can a cheaper series controller be used to activate the mosfets?


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## xtian999 (Apr 26, 2009)

It is made by General Motors for the GEM car. It is rated at 450 amps and 72 volts. It has about 22 mosfets on it. Some feed to the B+ and some to the B- and a few seem to feed F1 and F2 and each other. All are linked to the circuit board via two 8-line ribbons. 
I am not going to even try to reprogram the CPU it has now. I want to figure out which leads run which mosfets, what signals they need to work, and then remove the old controller board, including CPU, and run them with a known PWM chip.


Check back later for pictures.


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## xtian999 (Apr 26, 2009)

Here's a top view of the power board. This is what is going to drive a GE serial wound motor. The PWM has not yet been sourced.

The Power mosfets are ST60N10 rated at 100 v and 60 amps. Diodes are SF302A and rated 100v, 30 amps. Capacitors say 100mv, 680 up.

The leftmost pair of mosfets on the upper and lower side are connected to the F1 and F2 tabs, and everything else goes to A1 and A2.

Most of the leads on the two 8 strand ribbon cables will not be used.

Feel free to suggest options for the PWM generator and throttle portion.

Thanks,
Xtian


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