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In Section 9 we discussed electric motors and some, of their starting components. In this section we discuss the starting components used on single- phase hermetic motors. Single-phase hermetic motors and other special motors require some type of external starting component because they are enclosed in a sealed case. Three types of starting relays are used on this type of motor: current, potential, and solid state. These devices are used on most single-phase hermetic compressor motors with the exception of permanent split-capacitor motors.
Electric motors must have bearings to permit smooth and easy rotation. The ball bearing or the sleeve bearing is used in most motors. Motors also must have some means of transferring their rotating motion to the device being powered by the motor. A direct-drive hookup transfers the rotating motion directly from the motor to the device. The belt-drive hookup transfers the rotating motion to the device by a belt connection.
Magnetic starters and push buttons are used to stop and start electric motors. A magnetic starter opens and closes sets of contacts to stop and start loads. The magnetic starter also incorporates overload protection for the device it controls. Push-button switches are used to control magnetic starters in most cases.
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