VFD Problems
I have a mostly retrofitted Hurco KM3, replacing the relays with a Teco FM50 VFD that is also being used to convert the 220v single phase input to a 3phase output. The VFD works fine, but it also causes the servo motors to fluctuate slightly. It has vastly improved since I ensured all grounding lines were properly setup, but there is enough that i don't feel comfortable running the machine.
It looks like I might need an EMI filter, but I'm having trouble locating the right one for my application.
Also when the VFD has been on for a little while, maybe a minute or so, the servos stop running at all, which is almost certainly related.
Any help would be greatly appreciated.
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VFD 3ph inductor
In some cases I have put them in both, but some VFD manuf, suggest at least between VFD and motor particularly if a non-vector motor is used.
At 50 to 600hz, the inductive reactance is low, but offers a high impedance to the high frequency switching pulses.
There was another link here today showing a 1 phase reactor for the VFD that uses 1ph input.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
My main issue at the moment is that my VFD when hooked up to the spindle, causes the servo motors to run unwantedly, where would be best for this problem?
Make sure your VFD and spindle motor frame have a earth ground conductor.
Ground the PC case to the Earth ground star point and ensure all the metal work on the machine is bonded to ground.
http://www.cnczone.com/forums/phase_...se_issues.html
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
So the X and Y servos are pretty good, maybe one or two thou motion, while the Z can be as much as a ten thou jump.
I'm going to look to see if the servo amp board is well grounded now, or if I accidentally pulled that. The power to the Mesa boards is through the serial cable, do I need to worry about that getting well-grounded and/or do you have any ideas where to go about that?
I will double check that I'm running a grounded input to the control computer as well, although I'm pretty sure on that one.
Al, thanks so much for that link. Once I powered the daughter Mesa board off a 5v and Earth ground all is working right, hopefully I can test a full CNC'd path rather than just fiddling around with jogging soon.
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