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Posted (edited)

I bought a new VFD to use with the 2x72 grinder, it an H100 Remove live link to Amazon.

QNK 1.5KW 2HP AC 220V 7A VFD Converter Single to 3 Phase Inverter Variable Frequency Drive CNC Spindle Motor Speed Controller

I matched all the basic parameters to what is on the motor, and it just worked fine for the most part.

When I put too much pressure or lean in when grinding, the increased resistance causes the VFD to stop and throw an error code for "overvoltage", and I have to restart.  This is super annoying.  This never happened with previous VFD's, so I assume that I haven't set some parameter somewhere, any guidance would be much appreciated!

If you help me find a solution, I'm happy to ship you one of my blades :)

Edited by Mod30
Remove commercial link per TOS
Posted

Couple of suggestions/points:

  1. Amazon ad states that for heavy load use (like a belt grinder pressing hard) you need to select a VFD rated for 50% higher load than the motor nameplate.  For this one it would mean not using a motor larger than around 1.25 HP (so a 1 HP motor).  What did you use on your grinder?
  2. Ad also states that manufacturer will respond in 24 hrs to any setup questions.  Have you tried that?
  3. Inexpensive VFD are not your friend in a metal shop.  There is a reason that the better grinders are sold with a NEMA 4x case with heat dissipative fins.  The KB-27D is expensive, but a lot more reliable.
  4. Some VFD have torque limiting parameters.  Might want to look into those.

Good luck

 

Posted

I took a look at the manual.  There are various torque and stall protections settings you could try tweaking, around F 118 to F 124.  The overvoltage error is a little odd -- based on the not-very-clear description in the manual, it protects the VFD from excessive voltage the motor may generate the VFD slows it down and it acts as a generator.

I guess one possibility is that the torque protection is kicking in and slowing the motor, which in turn causes an overvoltage.  The first thing I might try is bumping up the rated motor current (F 140) an amp or two.  That might stop the torque protection from kicking in in the first place.  Don't go hog wild, though. . . 

If that doesn't work you could perhaps try setting F 123 to either 0 or 2.  That looks like it would let the motor continue to operate after an overtorque is detected.  (I can't tell from the poorly translated manual what the difference is between 0 and 2.)

And one final thought that I should have put first -- if you haven't already, check that the wiring connections are tight.  I don't have anything specific to base this on, but it seems like a loose connection might cause the VFD to do strange things.

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