I remember in college being instructed to put a 1000 ohm resistor across the terminals.But once out in the shop we were told to use our screwdrivers.I worked as a refrigeration/hvac tech for many years before becoming an industrial electrician.And in all that time never seen anyone use anything but a screwdriver on anything up to 370v 30 micro farads.I never understood why but if shorting the cap terminals caused an arc the the motor was usually bad.
Start and run caps are very cheap and the experienced guys just replaced it rather than screw around with a tester.If the costumer is paying $60 an hour and a 15 or 20 capacitor is suspect would i test it by simply installing a Known good one and trying to restart
If the tester falsely passes a capacitor and i replace a $500 compressor because of it i wouldn't sleep too well.I dealt with tons of these on a daily basis and replacing not testing was defiantly the way to go to avoid call backs.
