I have a 110v benchtop speed lathe that is operated by way of various switches. Inside of the lathe is a Baldor 90v 1/2hp brushed DC motor and controlling that is a KBMG-212D Regenerative drive. I've attached the technical document for reference. The controller is pretty straight forward, a +15v or -15v is wired through a 5k potentiometer where the signal leg of the pot is connected to a "signal" port. +15v is forward and the pot controls speed. This is labeled "Bidirectional with reversing contact" in the middle of page 2 of the attached document.
My end goal is to have an arduino connected to an external computer via modbus to control all aspects of the speed lathe (on/run,off/brake, fwd, rev, speed). For now I think i might be able to get by, by sending the arduino an analog input from the external "computer".
So these are my thoughts to control the motor.
1a. replace the current 3 position switch (which determines whether the +15 or -15v is going to the potentiometer) with a couple relays.
1b. Digital potentiometer? I don't necessarily know the best way of going about this. OR attach a small dc motor onto the original potentiometer to control that one?
2a. There is a "voltage following mode" Which my understanding is that an external +/-10v is applied and the speed and direction of the motor is based off what is given. So I thought maybe an arduino controlled stepdown from the 110v I have in the box? Use a couple relays....before the stepdown? to control polarity?
Any suggestions on how to accomplish this is greatly appreciated. I'm sure I left out a lot of vital information for those more knowledgeable, so please feel free to ask for clarity!
kbmg212d.pdf (612 KB)