M.B. Naegle
Diamond
- Joined
- Feb 7, 2011
- Location
- Conroe, TX USA
I could use some help from some of you electronics wizards on here.
I'm setting up my 1909 Hendey Engine lathe with a VFD, not for voltage or phase change, but for speed control. The lathe was a very early "electrically driven" machine tool that probably had a DC motor that was controlled by a mechanical selector on the carriage. The original electronics are long gone and were replaced with a 5HP 220v AC motor and a drum switch, but it still has most of the mechanical control parts on the carriage that I would like to put to use. So my solution is to stick with the AC motor but control it with a VFD and tie the carriage control into a small potentiometer.
The VFD has your standard remote control taps: three wires for a 1K potentiometer (common, high, low), and three wires for directional control (common, forward, reverse). Where I need your help is controlling it all with a single dial.
What I would like to do is have the lathe be off when the dial is in the middle of it's travel, speed up forward when turned to the right of center, and speed up reverse when turned to to left of center. What components would I need to do this? A dual range pot and a rotary 3 position switch? If it takes multiple switches, they'll all need to be able to connect to a single shaft. Is there a way to wire a standard pot to do this or is there a commercially available switch that does this? I'v considered making a cam with roller limit switches to control which side of a dual range pot is in use, but I wonder if I'm overthinking it?
From a practical stand-point, the goal is to have full control of the spindle at the carriage. The speed control would be helpful to adjust surface speed when cutting faces (speeding up as cutter gets closer to center).
I'm setting up my 1909 Hendey Engine lathe with a VFD, not for voltage or phase change, but for speed control. The lathe was a very early "electrically driven" machine tool that probably had a DC motor that was controlled by a mechanical selector on the carriage. The original electronics are long gone and were replaced with a 5HP 220v AC motor and a drum switch, but it still has most of the mechanical control parts on the carriage that I would like to put to use. So my solution is to stick with the AC motor but control it with a VFD and tie the carriage control into a small potentiometer.
The VFD has your standard remote control taps: three wires for a 1K potentiometer (common, high, low), and three wires for directional control (common, forward, reverse). Where I need your help is controlling it all with a single dial.
What I would like to do is have the lathe be off when the dial is in the middle of it's travel, speed up forward when turned to the right of center, and speed up reverse when turned to to left of center. What components would I need to do this? A dual range pot and a rotary 3 position switch? If it takes multiple switches, they'll all need to be able to connect to a single shaft. Is there a way to wire a standard pot to do this or is there a commercially available switch that does this? I'v considered making a cam with roller limit switches to control which side of a dual range pot is in use, but I wonder if I'm overthinking it?
From a practical stand-point, the goal is to have full control of the spindle at the carriage. The speed control would be helpful to adjust surface speed when cutting faces (speeding up as cutter gets closer to center).