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VFd parrallel operation

SHERSHA SHAMEER

Electrical
Apr 9, 2025
1
what are the parameters we need to consider during multiple motor connected on a single vfd. Is there any extra care need to take while connecting the parallel operation.
 
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First - what kind of motor? Squirrel cage induction, wound rotor induction, synchronous, or direct current? Or something else?

Chances are the machines are not going to perform exactly the same due to tolerance buildup in material properties and geometry, so there will be some inability to share load properly if they are connected to the same driven equipment. This gets worse if the rotor and stator both require power (e.g. anything BUT squirrel cage).

Second - from the sound of the original post it looks like you want to provide the drive's power output to more than one machine at the same time. This is different from operating one machine at time on the drive - either as a starter or as continuous running.
 
Yeah it can work fine but a few things to watch for:
All motors should be identical in type, voltage, and rating if possible
Total cable length matters for VFD output, especially with reflected wave issues
Overload protection per motor (you lose individual motor feedback with one drive)
If one motor fails or jams, the others will try to drag it along

Done it a few times on small pumps or fans, just gotta treat the group as one unit basically. You running them all at once or switching between?
 

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