Drivers

Abstract

During the history of centrifugal pumps, probably every form of prime mover and source of power, with some form of intermediate transmission when necessary, has been used to drive them. The prime movers commonly used today and the reasons for their choice are:

• Electric motor. The alternating current (ac) induction motor is simple, easy to install, and reliable, and is therefore the usual first choice of prime mover for any installation where there is an adequate ac electrical supply system. Alternating current motors are fixed speed unless of wound rotor construction or connected across a variable frequency power supply. Direct current motors are used only for special applications.

• Steam turbine. These are generally limited to (1) standby or emergency drives, (2) installations where steam has to be throttled, (3) applications where variable speed operation is required and steam is available, or (4) drives where the power required exceeds the economic capability of electric motors, typically a consideration above 7,500 kW (10,000 hp).