View Full Version : Are VFD 0-10V inputs isolated or tied to gnd?

21-09-2013, 09:16 PM
Is it safe to connect the COM on a VFD to gnd?

I've just realised I've never needed to worry about this before, but it's the first time I'm needing to connect a VFD to a 0 to +/-10V output that isn't isolated.
The inverter in question is an old KEB Combivert, and I can see nothing in the manual warning against not connecting the COM to gnd. Having scanned the manual for the Huayang inverter, it makes no mention either.

I'm just wanting to clarify before I blow the inverter and/or KFlop/Kanalog!

21-09-2013, 09:28 PM
It is "usual" practice to ground the 0v but I dunno about the drive you have. Have you checked continuity between COM and earth/heatsink?

21-09-2013, 09:33 PM
I've not checked continuity. It was something that occured to me while I was in the middle of sorting out all the old wiring, and thought I'd better check before I release smoke from anything.

21-09-2013, 09:50 PM
You'll probably find the COM is already connected to ground via the earth terminals and heatsink or mounting plate