[Joeztech]

Edisla;

The 30uF capacitor you are wondering about is a non-polarized electrolytic so that it can be used in and AC circuit. The motor in question is an AC powered motor which gets its voltage from a transformer and there are no rectifiers changing the power from that transformer to DC, so that is why they used a non-polarized capacitor. Do not try to use a single electrolytic with just a positive and negative lead attached across the AC to the motor. It will overheat and likely explode! To make a non-polarized electrolytic from two conventional DC type electrolytics you either connect two of them together by tying the two negative leads together OR tie two positive leads together and make connections to the motor using the two wires from the free end leads of the two capacitors. It is safer and usually takes up less space to just buy an AC rated motor run capacitor of the right capacitance. A film type capacitor made for AC service at 115-130VAC will work fine at 30VAC that the motor appears to operate at.

Joe