Hi all,
Long time reader on SMC, but just registered to ask a question I haven't been able to find much info about.
I'm likely buying a Robland x31 combination machine (the original 5 function machine that all the others today have copied). Its got 3) 4HP 3 phase motors, with one control panel that selects which motor to turn on, a power on switch, and several cut off switches around the machine near the various stations. Its currently being run on a home built rotary phase converter, but I was thinking of going over to a VFD setup.
I know in general you're not supposed to run multiple motors on one VFD, but was wondering if this setup where only one motor at a time can be selected to run at the control panel would be different, or would I have to split up the controls and run 3 separate VFDs on the machine? In the photo below, you can see the control board under the slider table. There's stop, then start button, then the knob to the right of that selects which motor will run. Knob below that I think is forward/reverse for the shaper motor, but not positive.
Also, I've read on here, I believe, that most 5HP machines will run pretty much at full normal rated load on a 3HP TECO due to the 50% overrun, which under most woodworking conditions would only happen rarely with such large motors... so with my 4HP motors, would a 3HP be sufficient? Would save a lot of dough. I plan on using the sliding table saw a good bit, the shaper a reasonable amount, and the jointer/planer only occasionally (use dedicated machines, but the planer can be a nice backup if I have an issue, and my regular jointer is 8", so when the need for a 12" jointer pops up, will be nice to have - but don't want to have to change machine setup every time I joint). This particular machine has the mortiser removed and mounted on a separate stand with its own motor (which is great, that thing seemed like it would be in the way).
Any thoughts on if a single VFD is feasible to just tie into the existing controls, or does all that have to be completely reworked if I want to go to VFD? I'd just like to get rid of the extra noise, size, hassle, and inefficiency of the rotary converter if possible.
Thanks for the help. I'm still new to phase conversion, but keep coming across great deals on 3 phase equipment and trying to learn.
Mike