Hi Larry,

Are you thinking Jacob's Ladder/spark gap? If so, I'd think the
discharges would melt the acrylic tubing in short order.

No. I'm thinking of machine which resembles a Van de Graaff generator. There would be a rounded aluminium terminal on the top. Like this:
https://sharepoint.umich.edu/lsa/phy...or_5A50.30.JPG

Not a clue. But how would you insulate the motor from the charge in
the first place?

The parts of the pump which contact the liquid are entirely plastic (PVDF). This is what set me thinking about the idea of a Van de Graaff with pumped oil again (I first thought of the concept with bubbles around 2001).

Chris