Running 2 motors simultaneously from a single VFD?

Thought I would create a new thread for this subject rather than tack it on to my Tree mill thread as the title might be of interest to other folks than Tree huggers.

My 2uvr-c has 2 motors to provide table motion, 1 drives the x and y axes via a gearbox and the other drives the knee. The knee motion is traverse only while the x and y drive motor has a built in mechanical speed control. I would like to provide the drive motors 3 phase power separate from the spindle 3 phase power.

The drive motors are both 0.5 hp, 240V 3 phase, 2.0 FLA 1800 rpm. Is it possible to drive both with a single VFD not using the the VFD speed control? If so, how would the setup be wired? I plan on using a Teco N3 for the spindle with an e-stop wired into the logic. I could use another N3 for the table and knee drives, would that allow me to use the spindle e-stop to provide e-stop capability for the other motors?

Please let me know what pics might be of any use.

Thanks,
Steve

If you truely were going to run two of the same motor simultaneously, the set up would be quite simple. But what you describe is not that.

By the time you put together the controls, relays and contactors required to protect the VFD from "across the line" switching, you will be money ahead to use two VFDs or better, A RPC.

If both motors are substantially identical (same brand/model/ratings) and see the same load (e.g., both driving the same conveyor belt), it can be done, but should be considered an engineered, rather than casual, solution.

Two different motors, with unrelated loads and independently switched, on one VFD? No way. As CalG said, much easier, faster and cheaper to buy two small VFDs or provide a more general purpose 3-phase convertor.

However, wiring one E-stop control (or series chain of controls) to all the motor drives would not be difficult at all. Wouldn't matter too much whether the drives are simple contactors or VFDs, although I suspect some VFD E-stop connections can't be trivially chained in series the way you would with contactors.

You need to go to the Fuji electric site and look at what they have and how this all works. Take the tutorial and study before connecting anything or powering up. Very good information. If using the Mega series , you can down load the parameter platform and down load your inputs to your VFD. You will have full control and the platform to tweak it with, free of charge.

I'm not sure Teco-N3 will do the job for you as your planning.

If you suitably over-rate the VFD, there is no problem at all in doing that. And no problem with switching them on and off independently.

But you will need a VFD with output current capability about 4 times the combined full load currents of the two motors, AND a 150% short term overload capability.

Switching a competently designed VFD output is not deadly.... it just doesn't do any good unless the VFD is over-rated as above, because you can't START the motors by switching unless it is over-rated.