Newbie- Dual 5 hp spindles

[ceencee]

I am a complete newb when it comes to the inner workings of a cnc but this build is going well with all your help. My next question which is probably an easy answer is can 1 vfd control 2 spindles or is it a 1 for 1 deal. All the sites dont say so im thinking its a one vfd per spindle deal. Any insight would be appreciated so we can continue on on our wiring schematics and get this router figured and built.
Thank you

[ger21]

Do you mean two at the same time, or only one at a time?

At my last job, our machine used one VFD for two 10HP spindles, with relays or contactors switching between the spindles. Only one was used at a time.

I don't know enough to tell you how to do it, though.

[ceencee]

Thanks Ger21

The spindles will be used separately so I'm thinking with some creative use of relays it can be done. If any one has any idea what this creative use of relays is, lol I would sure like to pick your brain.

Thanks
Wade

[ger21]

You might want to use a PLC to control them. You need to be 100% sure that relays don't get switched under power, or both spindles get power together, or sparks may fly.

[ceencee]

I am using a PLC to control the multi drill spindle block so i should be able to add some controls for the spindle power and controls for the pneumatics that drop the spindle that is in use. I hope that those PLCs are easy to program.
Now these are 2-5 hp colombo spindles, do i get a 5 hp VFD or do I go a little larger for performance issues.

Thanks
Wade

[Al_The_Man]

If using a PLC it will be relatively easy to program the logic so that either motor contactor is picked up or dropped out only when the VFD is at zero speed, usually the VFD outputs are customizable on most.
I did have one application where both double ended lathe spindles were picked up by one VFD.
Al.

[mike_Kilroy]

Originally Posted by ceencee Thanks Ger21 The spindles will be used separately so I'm thinking with some creative use of relays it can be done. If any one has any idea what this creative use of relays is, lol I would sure like to pick your brain. Thanks Wade

yep, just put a 3 phase contactor (relay) in series with each motor. then wire both of these to the vfd output. As AL said, u must be sure your PLC logic does not change either relay while vfd has output; best to interlock to only sw one or the other one on when 3 ph power to the vfd is OFF.

no oversize of vfd required. just make it a 5 hp model.