3-ph motor, with VFD AND mag-starter?

[Allan Speers]

I'm considering a used, industrial cyclone.
It has a 5 HP 3-ph motor, so of course I'd add a VFD.

But the thing that hangs me up is, it has what appears to be a mag starter.
(It could just be a larger start-stop-reset box, but the seller doesn't know)

So how would that work with the VFD? Could I put a VFD upstream of the starter, or would I simply replace the starter, and wire external buttons to the VFD? I think probably the latter, but I'd like to know my options.


thx.

[Malcolm McLeod]

I'm considering a used, industrial cyclone.
It has a 5 HP 3-ph motor, so of course I'd add a VFD.

But the thing that hangs me up is, it has what appears to be a mag starter. (It could just be a larger start-stop-rest box, but the seller doesn't know)

So how would that work with the VFD? Could I put a VFD upstream of the starter, or would I simply replace the starter, and wire external buttons to the VFD? I think probably the latter, but I'd like to know my options.


thx.

Ditch the existing starter. It will add nothing. In particular do not put any power interruption devices between the VFD and the motor. If the motor is disconnected from the VFD while under load, you’ll probably need a new VFD.

It may be possible to re-purpose the push-buttons or switches - depending on the particular VFD, the way you configure it, the switches operation, and if you find their current locations convenient for your use. Some VFDs can be configured to use either the on-board keypad, or external switches, and sometimes both.

[Allan Speers]

Thanks, Malcom.

That's what I thought, but I wasn't 100% sure.

Also, that's a great idea to re-purpose the starter. That should be easy with the TECO's, which I've used before.
I'll just remove the heaters, etc and use the raw buttons + the enclosure.

[Dick Strauss]

Just make sure you don't put the switch between the VFD and motor!

[Bill Dufour]

many VFDs run a small buzzy fan as long as power is connected. On my lathe I used the old contactor to supply power into the vfd. I installed a small pushbutton station to control the vfd power supply. I used the original switches to control the vfd. When I am done using the lathe it is now dead quiet in the shop.
Bill D