I recently had a problem with my compressor starting (it wasn't getting up to full speed before the centrifugal switch opened). The caps tested OK and it would start fine if the tube between the pump and tank was disconnected. So as a work-around I plumbed a solenoid valve into the line between the pump and tank and connected it to the centrifugal switch. The idea was that the valve would be opened when the motor started and would stay open until the motor was up to speed and the cent. switch opened. This would unload the motor until it was up to speed.
Well, I was surprised and puzzled by what happened. Do you know?
See my reply for the answer.