Two induction motors paralleled to one VFD output?
Two induction motors paralleled to one VFD output?
(OP)
I was wondering if there were any special considerations that should be known befor attempting to parallel 2 identical 3-phase induction motors on one vfd output.The motors will be driving a sled via rails. There will be a motor and gearbox at each side of the cart to drive the cart on the rails. I do know that I will need to upgrade the capicity of the regen brake module and resistors, but what else will be different from just having one motor on the output of the vfd?





RE: Two induction motors paralleled to one VFD output?
Running vector mode may give you a mental problem (what motor ID shall you use?). Some drives can auto-identify a twin motor and some will not. Sometimes it is OK to enter half the Ls value and half the Rs value. There are usually some hints given in the manual. If not, ask the supplier.
Your drive will have to supply both motors with magnetizing current. So you may need to have a larger drive than you expect. It is not just two motors that share one mechanical load.
Gunnar Englund
www.gke.org
RE: Two induction motors paralleled to one VFD output?
These faults usually are Output Short Circuit or Output Overcurrent faults.
RE: Two induction motors paralleled to one VFD output?
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Two induction motors paralleled to one VFD output?
Otherwise just use one controller with seperate overloads as above. This is how most gantry cranes are controlled.
Cheers.
RE: Two induction motors paralleled to one VFD output?
Gantry cranes were controlled for decades with an induction motor on each side. Some were wound rotor motors, some were two speed motors, some were single speed motors. They often had brakes and the brakes often induced skew when they were not properly adjusted.
The slip in the induction motors did a pretty good job of running straight and correcting the skew induced by the brakes.
Try running in open-ended Volts/Hertz mode. If you need closer control you can use a speed transmitter and a PI or PID controller to forward the setpoint to the VFD controller.
respectfully