Solved: Help with Busellato JET 2 spindle retrofit – VFD overload

Hi all,I’m in the process of retrofitting a Busellato JET 2 CNC machine. The machine has one main spindle, a side spindle, and drills, but I only need to control the main spindle.The spindle is still running on the original VFD, which has not been altered or replaced.Originally, the VFD was controlled via serial communication, but since I’m using a Mesa 7i77 card, I converted it to 0–10 V analog control (the serial setup seemed unnecessarily complex and hard to understand).Here’s what I’ve tried so far:

• Using the original VFD (unchanged).
  • Converted VFD control from serial → 0–10 V (Mesa 7i77).
    • Adjusted VFD parameters to allow external analog speed control.
      • Able to start the spindle successfully.
        • Spindle ramps up but only reaches ~50 Hz.
          • After about 10 seconds at 50 Hz, the VFD trips into overload.
            
            My observations:
            • It sounds like the spindle wants to accelerate further but is somehow being held back.
              • I’ve spent several hours tweaking and checking parameters, but I can’t figure out where it’s going wrong.
                
                Any tips, suggestions, or guidance on how to properly configure the VFD (or what to check mechanically/electrically) would be hugely appreciated.Thanks in advance!
                
                Omron F7 guide
                
                Omron F7 full manual

The VFD on my high-speed spindle feels a bit like this, it starts sluggishly then seems to nearly get stuck, but in my case it then accelerates away to commanded speed.

Make sure that you really are getting 10V (or whatever) on the analogue voltage input to the VFD using a multimeter. (Also check the polarity...)

You could try operating the VFD with a potentiometer in the conventional way to check if the behaviour is the same.

ah okay, i will take a poteniometer with me next time. the machine is not close by. are there other things you might suggest? i was thinking of maybe doing the auto tune with the vfd, if i can figure it out.

Do you also think that i force it too quickly to high freq or just too slow?

Also a picture of the spindle, in case it helps some insight

GDTH wrote:

ah okay, i will take a poteniometer with me next time. the machine is not close by. are there other things you might suggest? i was thinking of maybe doing the auto tune with the vfd, if i can figure it out.

Do you also think that i force it too quickly to high freq or just too slow?

Also a picture of the spindle, in case it helps some insight
 

Yes, it might solve the problem if you add a limit3 (I think that is the name of the hal component) to slow down the change of the spindle speed value.
Jon

Yesterday I tried running the VFD with a potentiometer, but had no luck. I experimented by slowly adjusting the frequency and changing some basic parameters to see if I could get any results. The only thing that seemed to have some effect was changing the V/f pattern.

Right, I think the V/F profile is wrong. You were showing 32 Amps on the Omron display when it overloaded. it needs to have the V/Hz turned down quite a bit.
You need to check the spindle manual to find out the correct V / Hz rating and then program that into the VFD.
Jon

Yes, there was one parameter I hadn’t interpreted correctly. Now the spindle reaches high RPM smoothly. You can still hear it struggle for a split second at low RPM, but that doesn’t seem to be a problem.