I thought that "REV" stands for "revolution" or "start motor revving" command. I don't think that controller has the reversing ability after all. I tried to trick the controller by connecting the 13v output to the REV but no luck.
Doesn't the console have a Reverse button? Some treadmills do (e.g. the Landice L7-RTM-REV). The REV terminal is possibly expecting/sending a logic-level signal, so connecting 13V to it may have caused damage.
Typical PWM traces: Note that the amplitude of the pulses is always the same. What varies is the difference in the duration of the pulse length. This difference is what speeds up (longer duration) or slows down (shorter pulse length) a motor.
In your controller, the IGBT (40N60) is really designed to act like a pulsed switch - simply on or off, for varying periods of time (with very fast transitions), and it reacts to a very low input signal level (saturation ≈ 2.1Vdc = 100% IGBT conduction). Thus, the pot mod you are considering won't (can't, really) work.
I apologize for not noticing this earlier.
And that's what lead me to suggest using the console/motor as is.
<EDIT>Frequency is also an issue, but for the sake of the argument, I didn't mention it.
Thanks. I have already ordered two PWM drives from China. They are on the way. One is 1500w and other is 4000w rated for 210v PM motors. Good thing, they are big. Not very small like my beloved KB drive because its components are too small to solder and replace.
As for the controller we are fighting, I think I need an oscilloscope to figure what kind of signal/voltage actually send and receive the controller and the console, right? Then maybe some Arduino work would help bringing it to life. This may be be a winter project for me. Because I'm building a CNC lathe from scratch and I'll need a good PWM drive for it to drive the spindle motor.
I thank you all (especially BOB) for your hospitality and help.
And yes, an oscilloscope is an enormously useful tool. There are many to chose from but I would suggest a DSO (digital storage oscilloscope), like one of these: https://www.sainsmart.com/sainsmart-dso-note-ii-oscilloscope.html. And I have one of these:**broken link removed** that is very handy for holding the 'scope.
I have a similar device and I have used it for years. They are not the best nor the most capable but for the money and the type of electronic work I do (and what I perceive as your usage needs) , they're perfect.
Good luck with the CNC project. That sounds like a lot of fun .
I'm here again with another stupid question. I have 2 large contactors in the control box of my lathe. They are there for the reversing job.
The new controller I recently ordered is slightly bigger than my old KB drive and there is no free room for it in the control box. So I thought if I could replace the contactors with smaller relays then I can make some room for the new controller. However, I don't know how to wire the relays.
If you help me on wiring these I'll be very appreciated.
How were the original relays wired? How was the reversal controlled (I'm assuming it could not be reversed if the motor was turning).
Simplest example of wiring for a motor reversal, using 2 SPDT relays: View attachment 102334
The relay control wiring will depend on your current set up.
The new controller just arrived. It's twice the size compared to my old KB drive. Unfortunately there is no free room for it in the control box. So I need to figure how to replace the big contactors with smaller relays.
I'm still unsure what the switching scheme you refer to (1-0-1) means.
And are there two of the NO switches (LAY4-BE101 as you showed in Post#53) or just one?
And where do the relays you refer to figure into the switching?
I guess I need you to explain to us (or at least me, as a non-lathe savvy person) what the step by step process is for starting, stopping and reversing the spindle motor.