test a hermetic motor, a procedure tha involved holding an energized lead, and touching it to a terminal pin.

I wish I could draw the picture he has in the book, but he has a two prong pigtail with the common and the run attached and a jumper on the start terminal.
He tells you to plug in the pigtail and the "pot" will hum
With the "pot " humming , touch the jumper to the runwinding and it will start.

You may find this hard to believe, but thats how we were shown in school.

and of course you are then left holding 340 volts that are looking for a ground (on a 110 motor)