Hey MaxHeadRoom, thank you, I looked at KB Controls (simply blown away with their array of devices), however, I wasn't able to find anything foot operated and, honestly, I have the feeling I am opening a can of worms precisely because of that: too much to chew... To make an informed choice to navigate through their list of devices, I would probably have to first buy a manual of advanced electronics, learn everything in it and only after that I might be able to discard the items which won't help my purpose, probably to be left with at least 10 contraptions to further choose from (the fine tuning of choice so to speak). Yikes!
Also, by looking at the PWM MC2100 TM controllers, I see the need to pair it with a foot pedal, and researching for one, I now landed in the conundrum of what type of pedal to use to do just that. The way I look at it now, the simplest "pairing" would be a pedal which mechanically rotates the speed knob (probably a variable resistor), because anything electronic would add a new layer of compatibility with the input the variable resistor gives to the controller. Am I wrong?
Diver, a big thank you to you, too. Ha! I wish I'd have the treadmill controller, but the motor was already pulled when I purchased it from a garage sale. Same regret about the original 90 V power source...
After reading your suggestion, I am left with the big question - what would be the contraindication or draw back for an analog polarity switch (rated for that amperage, obviously) I am tempted to use at this stage of the planning? I mentioned that probably the manual operation to change the rotation makes the most sense (I see that most of the ready made pottery wheels have some kind of a "gear lever" which, very likely, mechanically engage a reversing pulley or something). Not the direction I want to steer towards.
Really appreciate your time (and patience...)