I have 2.2kw spindle and most of the milling I have done to date has been around 16k or lower. I have recently done some milling at 24k. When these jobs completes and the spindle is instructed to go to zero RPM it is programmed to coast to a halt. However, even with coasting, I have experienced, I believe, regenerative energy from the spindle wind-down causing the VFD to trip with an overvoltage. If this is the correct diagnosis then the fix is probably is a braking resistor - but which one? I have an Optidrive E3 from Invertek. I have reached out to the UK 3Dtek support guys but thought I would also ask this learned audience. Cheers.
I don’t have a spindle, but I previously used big electric motors and VFDs in my day job. With high inductive loads (which can be caused by deceleration from high RPM) You absolutely do need a breaking resistor.
The documentation provided by @Aiph5u is a good start.
I stalled braking resistor. Easier than I feared (I fear too much ). Slide in the back, two wires to the terminals at the front and program change to parameter P-34 to 1 to enable the brake chopper with software protection (not what that means, but I did as instructed). I left P-05 (stopping mode at “coast”, value 1).
Image: black cable goes to the thin sliver of gold coloured this is resistor slid into the back cables tie in a front.
This I would change to “0” or “2” (ramp to stop) if you want the spindle to be decelerated from base frequency to standstill within the time set in P-04 (default 5 seconds)
Hi @Aiph5u i will look at your suggested config changes.
…and tripping was stopped. Brilliant. It means that i can use F360 variable speed settting (e.g. in corners) . before the breaking resistor, when F360 gcode signalled a drop in speed, the vfd tripped with over over voltage. Also when i had to do an emergency stop, by whatever means, it also tripped and took forever to stop spinning.
). Slide in the back, two wires to the terminals at the front and program change to parameter P-34 to 1 to enable the brake chopper with software protection (not what that means, but I did as instructed). I left P-05 (stopping mode at “coast”, value 1).
