Don't worry about going back to 3 phase after using a VFD you'll never want to.

I'm not familiar with the boxford switches but if they are momentary you'll be able to use them with a 3-wire control setup, if they act directly on the contactors it's a lot less straightforward;. TBH you might be better off knocking up a simple pendant control. Few, rev and speed can be done with a 3-way switch and a potentiometer is no time at all.

The white box is a NVR starter you won't be able to use that but you most probably would be able to use the original drum switch to the left of it.

EDIT you could use the NVR as a power switch to supply the VFD but you wouldn't be able to use it as a start/stop and depending on what model VFD you get using the E-stop on the NVR might invoke motor braking or it might allow it to run down normally. Killing the power to a running VFD is not recommended.

Edited By Pete Rimmer on 09/05/2022 21:58:26

Check the motor can be wired Delta 240v.

If it turns out to be hard wired star, don't immediately reject the motor. I recently rewired such a motor by digging out the star point on the windings. It wasn't difficult to do.

Regarding all the existing switch gear, I would ditch the lot when fitting the VFD. A modern rotary or toggle switch is easy to wire up for controlling motor direction.

3 phase input VFD would suggest a 380-415v AC supply so not suitable for a unit designed for 230v AC single phase supply.

Emgee

sometimes photo orientation can just be a matter of being left handed especially if you are using an iPad or similar as most devices are made for right handers (they Arte the ones who ask you to do up an awkward nut for them)!!!

I've done my CUD with original motor and a Mitsubishi VFD. I was accustomed to the original stop start switch and much prefer it to buttons so I devised a wiring scheme to retain it. I had to dismantle it to rearrange the contacts and some were burned out but there were enough usable to do what I needed. Photo shows my prototype enclosure to be remade in steel when I get round to it, and you can just seen the VFD tucked into the cabinet. I have also attached my schematic wiring diagram. Please note, I am not an electrical engineer, this was devised with help from this forum and from the chap at Inverter Drive Supermarket who is a mine of information, so use at your own risk. It has been working without any problem for a year or so.

William.

Edited By William Chitham on 11/05/2022 12:55:03

Edited By William Chitham on 11/05/2022 13:03:23