Tag Archives: CNC

GEC Gemini motor controller is working

I got a Boxford TCL 125 CNC lathe a few years ago that I have been working on getting up and running. I gutted all the electronics except for the spindle motor controller, and replaced the stepper drivers and built a PC right into the lathe enclosure. I’ll post more on those upgrades later. All the new stuff I added is working fine, it is the old GEC Gemini motor controller that was giving me a hard time. But, after reading this post I got it working, it looks like I was just missing the kill switch connection.

So here are the connections to the big orange header:

  1. NC
  2. 0-8 VDC – This sets the motor speed
  3. 10VDC – Supply voltage for the controller
  4. NC
  5. NC
  6. NC
  7. GND
  8. GND
  9. Kill switch input – This needs to be connected to pin 3 for the motor to run
  10. GND
  11. NC
  12. NC

It looks like there are traces on the PCB that go to the pins that I have labeled as NC, but I’m not sure what they are for and the motor is working without them. If you know what they are used for leave some feedback.

Here we go…

So here goes the first post to the ckdevices blog.  It occurred to me that I seem to have no shortage of interesting projects on the go relating to electronics, PCB design, microcontrollers, embedded firmware, automation and CNC machining. So in an effort to give back and share my experience I thought I would start blogging about it. I hope you find it as interesting as I do.