I am working on a stock feeder / power feeder (used with woodworking equipment). It has an 8-position drum switch to control both fwd/reverse direction as well as vary the speed. The ON positions of this switch are:
- Fast - forward
- Fast - reverse
- Slow - forward
- Slow - reverse
as well as 4 OFF positions.
The motor itself has 6 leads (as shown in the diagram) which are all switched. My understanding is that the speed control function of the switch works by changing the topology of the motor coils with respect to each other and to the 3 phase inputs.
I would like to replace this switch with a VFD, both to run the machine on single phase power and also to provide more granular speed control.
The essence of my question is: what's the best way to wire the motor-side of the VFD? Is the "slow" or "fast" wiring topology more appropriate? (Or, would either work?) Assuming that is determined, what is the correct wiring combination of motor leads that would achieve said topology? Just from studying the diagram below its not clear to me what that is.
I could perform resistance tests or other inspection of the motor or existing switch, if that information would be useful.
Here's the control switch:
Each of the non-animal positions are OFF.
The motor is integral to the machine... its not a separable standard mount motor. It has no nameplate. However the plastic switch housing (also integral to the machine) has this:
Manufacturer's wiring diagram:
I've compared the diagram to the actual machine and its pretty accurate. Annoyingly the leads on the motor are all labelled with the same number (all red leads are "4" and all yellows are "2"!) but I can distinguish them with the help of the diagram.
FYI I originally had it on a static phase converter but it ran quite hot, that's one reason for the VFD idea.
It may help someone else trying to do the same thing to know that this was a Powermatic model PH-3 (aka PF-34). Maybe it will turn up in web searches.