I currently have two 3kw 220v spindles that are running on two separate 3kw VFDs. The second spindle is mainly used to mirror the first spindle so RPMs are always the same. I’m looking to add two more spindles. To save room in my controller cabinet, would it be possible to swap out the VFDs to larger 7.5kw versions and run two 3kw spindles per 7.5kw VFD?
I'm no expert, but I don't think that will work: The VFD needs to 'lock on' to the voltage / current feedback from the motor to determine what the motor is doing, and I can't see that being possible where two motors are connected at once (one could be turning, the other not - what should the VFD do?).
For proper confirmation (and backing should it go wrong) get the VFD Supplier's advice (they would be better able to tell if their product can do what you need, and maybe good to have it in writing so it won't affect warranty etc if it does cause any issues)
