On/Off switch for VFD

[kencnc411]

I am still fooling with the box for my 3HP VFD.

I was thinking it would be nice to have a switch on the hot 110 wire, so I could leave the VFD plugged in. It would also allow me to put a fuse on the enclosure. The VFD has no off switch, so it sucks electricity even when it's not in use. It seemed like to be able to turn the AC supply on and off after shutting the motor down. The in-rush at initial power-on of a VFD whose capacitors are charging creates a extremely sharp current surge that can weld contacts on a switch. Ask me how I know.

Does anyone know how much stress a VFD will put on a disconnect switch at startup? Any recommendations for a VFD powering on and off?

 

[testyourdesign]

@kencnc411

Have you considered using a solid-state relay connected to the main power switch you use to turn on the machine? I have mine on a separate heavy-duty on/off switch but I plan on combining the main power controls using an appropriately rated solid-state relay when I upgrade to the G3.

Cheers, Stephen Brown

 

[metzenovich]

If you find a contactor with 24V DC (not AC) coils you can have it so the VFD is only on when the Masso is on. Or potentially so the VFD is only powered when the Masso isn't in e-stop. Then if there is an e-stop the VFD will shut off immediately.