MetalworkingFun Forum

Back in November I read of someone buying a 5hp VFD for $333.58 Cdn + $20.00 shipping, to Canada!
From
VFD

I wondered if I could power the lathe AND the mill with one.
I've never used both machines at the same time, so all I'd need is some kind of switching interlock that would only
allow switching from one to the other when the inverter input was off.

I decided to take the plunge, even if it would only do for my mill at least I could re-mount the 3 hp 3ph motor on the
mill and have much improved power and speed range a selectivity.
If I can work out a way to select between the mill and my lathe I could re-install the 5hp 3ph motor it came with
instead of the 3hp single phase one I installed.

It arrived yesterday by FedEx and ended up costing me $374.70 PLUS $95.73 to FedEx for Customs Duties, Sales tax,
rod fee(?)and even $1.50 tax on the Rod Fee(I forgot to ask the Fedex driver what "rod Fee is).
So I now have a $470.43 VFD to play with.
More to come in the future, hopefully not involving loss of magic smoke.

I am running both a lathe and a mill off the same VFD. Both of mine have 1 1/2 HP motors, but one is 1725 RPM and the other is 3450. Works fine.

I set up a relay interlock system that cost as much as one motor. It uses an output from the VFD to prevent switching from one to the other while the first motor is running. I have a MachTach built into the remote control panel. The relays also switch between the two tach input sensors.

Mike, What kind (make) of VFD have you got?
If you could post (or PM me) a schematic diagram of the relay interlock system I'd appreciate it.

My VFD is a Teco FM50, rated up to 2 HP.

I'm sure I did up a sketch of the relay system, but I can't think of where it might be now. Sorry.

Why not a simple twist lock plug on the inverter and one on either machine, Don't turn it on unless a machine is connected, come on Steve your not that old and senile YET

(12-12-2013, 12:34 AM)f350ca Wrote: [ -> ]Why not a simple twist lock plug on the inverter and one on either machine, Don't turn it on unless a machine is connected, come on Steve your not that old and senile YET

Greg, I'll have you know that I am certifiably senile!
Now that that's established, I was just thinking of something foolproof(senileproof) that would be quicker and easier than plugging and unplugging.
I'm leery of having a plug on the output of the VFD, too much chance of disconnecting or connecting while the vfd is energized, apparently that's a NO-NO.