I just made first cuts with the new AV40S spindle then attached my dust shoe and surfaced my spoil board. I thought I saw something while the dust collector was running and watched a bit more intently and noticed that there was an occasional arc of electricity between the aluminum dust shoe base and the bottom of the spindle. It only happened about every 10 to 15 seconds.
My dust collector is a Powermatic centrifugal with a bag. I have it attached to a piece of PVC pipe that extends about 15’ towards my Avid machine, then a hose connects the two. I don’t have any grounding on the PVC or hose itself. I’m assuming that static is building in the hose/PVC thus charging the aluminum shoe plate and discharging to the spindle when it gets strong enough. I’ll look into grounding the hose and the PVC piping as I assume this will remedy the issue, but thought I’d post the issue here for other advice if warranted.
I never noticed this with the standard Avid 4hp spindle, but I may have just never seen it.
If you don’t have any path for the discharge, it will just continue building up the voltage until it can discharge, and then it starts all over again. If its jumping the gap on that spacer, then its at least hitting 10KV. Its not actually going to hurt anything doing that since its jumping to ground. However, if you are building that much up on the hose, it could come in contact with your motor or sensor wires and travel back to the electronics which can be bad news. A charge like that can destroy the input/output if just about any integrated circuit.
As always you are a wealth of information. I ordered the hose and will install per your recommendation. I really appreciate what you do for this community.