Examines primary distribution systems which feed controllers. Describes main line disconnects and fuses and includes troubleshooting hints to isolate problems. Details the different types of motor control systems found throughout the industry, including AC drives, hydraulic control, Ward Leonard configuration, static drives and the variable voltage, variable frequency (VVVF) drives. Addresses motor protection against overloads and phase reversal as well as the different brakes used on the hoist motors.