My wife is into pottery, & is looking at used potter's wheels. Generally, these things will run forward & reverse. One we are looking at will only run in one direction. I'm thinking the most likely culprit is the fwd/rev SWITCH (cheap/easy to fix), but I'm wondering if it may be the MOTOR. I'm not sure how such motors are reversed. Could the motor itself be defective, e.g., could it be they use a separate winding inside the motor for each direction, and one of them is open? How exactly do reversible ac motors reverse direction?