A properly made VFD should have nothing between it and the motor, except
perhaps a manual disconnect, which you'd only open after the input power is
disconnected. If the VFDs have a remote control input like RS485, USB, a
network jack etc. it should be possible to use an SBC like a Raspberry Pi or
Beagle Bone to have a single control input and multiple outputs. If high
precision matching of the motor speeds is required a setup like that could be
programmed to individually adjust the signal to each VFD and motor pair. Get
things mapped well and when you turn the control to 500 RPM you could be
confident that all the motors are turning really close to that.
If the VFDs have a way to sense if the motor is actually turning at the desired
speed, and can communicate through their remote port, you could have remote
sensing of motor failure or jams and have the SBC shut it all down.
On Thursday, August 15, 2019, 5:54:36 PM MDT, Todd Zuercher
<to...@pgrahamdunn.com> wrote:
I am preparing to install a half dozen el cheapo Chinese VFDs on a machine.
Any one have any idea if I need to or should be putting input line filters on
them? No mention of anything like this in the Chinglish manual. If so how do
you choose what size? Could I use 1 big one, or will I need a separate one for
each drive?
How about rectifiers on the output lines? I'm assuming those are rated by kva.
They are 3ph 220v 3kw drives and spindle motors.
Is it possible to set the speed on all of these using a single analog command
signal (they will all need to run at the same speed anyway.)
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