" GE " make Synchronous Motors are constant speed machines i.e running at its synchronous speed.

Synchronous motors are capable of being operated under a wide range of power factors, both lagging and leading. Hence, it can be used for power factor correction purposes, in addition to supplying torque to driven loads.

1) Because of high efficiency and high speed synchronous motors (above 600 rpm) are well suited for loads where constant speed is required such centrifugal pumps, belt-driven reciprocating compressors, blowers, line shafts, rubber & paper mills etc.
2) Low speed synchronous motors
(below 600 rpm) are used for drives such as centrifugal and screw-type pumps, ball and tube mills, vacuum pumps, chippers and metal rolling mills etc.
3) Used for voltage regulation of Transmission lines.

DC motors requires a basic understanding of the design and operating characteristics of the various types available: the series motor, the shunt motor, and the compound motor. Each type has unique operating characteristics and applications.