Part 2/9:
At the heart of the gyro compass is a rotor, which is a 10-inch diameter component weighing approximately 55 pounds. This design concentrates the weight at the rim of the rotor and allows it to spin at speeds of 6,000 revolutions per minute (RPM). Unlike typical models that rely on an external power source, the rotor in a Sperry Mark 14 gyro compass is driven by a three-phase induction motor. Specifically, the rotor bars and laminations are affixed internally, with field windings directly mounted to the case.