Hi, im stumped. One of my co workers wants to do a solution where they run 6 single phase motors off a 1 three phase inverter... I am not entirely sure if it is even possible to get it to do anything. Anyone has any thoughts on why this might be really bad idea besides the fact that it is as far as one can get from what those things are made for...

 

Apparently this works...

 

This is a good idea because it balances the load among the three phases. This is what they do in factories with lotsa motors. These factories also put a bunch of capacitors on each leg to counter the inductive load and reduce power factor as close to zero as possible. You know,
Z = R + jX.....

 

Apparently this works...

Hopefully if doing it like that the motors don't need to be synchronized, even motors made on the same day in the same place will have subtle speed differences.

 

I once retro fitted a double end lathe where both head stock spindles where controlled by the same VFD, IOW they had to rotate at exactly the same RPM as the material was clamped by both head-stocks,
The manuf. WEG assured me it would work for identical motors.
It turned out fine.
I would be hesitant to use 6 motors on one VFD, particularly if not all identical motors.
Max.

 

I would be hesitant to use 6 motors on one VFD, particularly if not all identical motors.

But his motors are single phase, being controlled by a 3phase VFD.

 

But his motors are single phase, being controlled by a 3phase VFD.

Missed that, I predict many issues if trying to run 1ph motors off of a VFD.
They don't even run that well off of VFD's intended for 1ph!
Max.