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.
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.