Nice technique but resistance is a DC measurement, I would expect a VFD to want the AC equivalent (impedance). I wonder why it wants resistance as a parameter if it's not braking. And just to be persnickety, bear in mind the meter measures current the same way you are albeit with a smaller internal resistor, so you have to factor that resistor in to your math for the best accuracy. But I imagine that's close enough for the VFD :)
The VFD does have some 'internal' braking features (as opposed to external braking resistors which are also supported) but its not clear to me if this parameter is used by these features. According to my VFD documentation, the following parameters are "essential for good operation" in vector control (aka field-oriented control) mode. Param Description Default Unit P399 Motor Rated Eff. 67.0 % P407 Motor Rated Power Fac 0.69 P409 Stator Resistance 10.63 ohm The "Stator Resistance" parameter is in ohms with a valid range of 0.01 to 99.99. The default setting is 10.63 ohms which I find oddly specific. My measured value is an order of magnitude smaller so I'm glad I at least tried to measure it. Hopefully my ballpark figure will work.
Quick question, I’m having some shorting issues with my spindle. I check the 4 leads at the top of the spindle and uvw have continuity between them? Is that normal?
Yes, continuity between U,V,W is normal (required in fact). It's useful to know if your spindle is wired internally as a WYE or a DELTA configuration. In either case, continuity between each of the three windings is expected. You should check the resistance of each winding (interpreting the results differs based on whether your spindle is a WYE or a DELTA). Here is a link to a 3-phase motor testing overview www.electricalengineeringtoolbox.com/2015/12/how-to-test-three-phase-ac-motors.html . I recommend disconnecting the cable between your VFD and spindle, and verifying those wires do NOT have continuity with each other (that is where my fault was).
Nice technique but resistance is a DC measurement, I would expect a VFD to want the AC equivalent (impedance). I wonder why it wants resistance as a parameter if it's not braking.
And just to be persnickety, bear in mind the meter measures current the same way you are albeit with a smaller internal resistor, so you have to factor that resistor in to your math for the best accuracy. But I imagine that's close enough for the VFD :)
The VFD does have some 'internal' braking features (as opposed to external braking resistors which are also supported) but its not clear to me if this parameter is used by these features.
According to my VFD documentation, the following parameters are "essential for good operation" in vector control (aka field-oriented control) mode.
Param Description Default Unit
P399 Motor Rated Eff. 67.0 %
P407 Motor Rated Power Fac 0.69
P409 Stator Resistance 10.63 ohm
The "Stator Resistance" parameter is in ohms with a valid range of 0.01 to 99.99. The default setting is 10.63 ohms which I find oddly specific. My measured value is an order of magnitude smaller so I'm glad I at least tried to measure it. Hopefully my ballpark figure will work.
Quick question, I’m having some shorting issues with my spindle. I check the 4 leads at the top of the spindle and uvw have continuity between them? Is that normal?
Yes, continuity between U,V,W is normal (required in fact). It's useful to know if your spindle is wired internally as a WYE or a DELTA configuration. In either case, continuity between each of the three windings is expected. You should check the resistance of each winding (interpreting the results differs based on whether your spindle is a WYE or a DELTA). Here is a link to a 3-phase motor testing overview www.electricalengineeringtoolbox.com/2015/12/how-to-test-three-phase-ac-motors.html . I recommend disconnecting the cable between your VFD and spindle, and verifying those wires do NOT have continuity with each other (that is where my fault was).