Hum, never even thought about that. The rheostat normally would be line voltage, not between the coil wire and rotor. I wonder if someone added that. If the condenser checks good and it were me, I think I would remove the rheostat and run without it. A normal coil wire is thicker to keep you from getting shocked by the higher amp/voltage it carries. The wire inside, without one in front of me to check, guessing off the top of my head is around 14 to 12 gauge wire, maybe smaller.