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+255 765 121314 PLEASE CALL ME, AND TELL YOU ABOUT ANY EVENTS. Railway electrification system From Wikipedia, the free encyclopedia Jump to: navigation , search Electric locomotives under the wires in Sweden Overhead wire and catenary in Bridgeport, Connecticut , United States A railway electrification system supplies electrical energy to railway locomotives and multiple units so that they can operate without having an on-board prime mover . There are several different electrification systems in use throughout the world. Railway electrification has many advantages but requires heavy capital expenditure for installation. Contents [ hide ] 1 Characteristics of electric traction 2 Classification 3 Direct current 3.1 Voltage 3.2 Overhead systems 3.3 Third rail 3.4 Fourth rail 4 Alternating current 4.1 Low-frequency alternating current 4.2 Polyphase alternating current systems 4.3 Standard frequency alternating current 5 World electr

+255 765 121314 PLEASE CALL ME, AND TELL YOU ABOUT ANY EVENTS. AC Induction Motor where n = Revolutions per minute (rpm) f = AC power frequency (hertz) p = Number of poles per phase (an even number) Slip is calculated using: where s is the slip . The rotor speed is: [ edit ] Synchronous Motor A synchronous motor always runs at synchronous speed with 0% slip. The speed of a synchronous motor is determined by the following formula: where v is the speed of the rotor (in rpm ), f is the frequency of the AC supply (in Hz ) and p is the number of magnetic poles. For example, a 6 pole motor operating on 60 Hz power would have a speed of: Note on the use of p - some texts refer to number of pole pairs per phase instead of number of poles per phase. For example a 6 pole motor, operating on 60 Hz power, would have 3 pole pairs. The equation of synchronous speed then becomes: with P being the number of pole pairs. For P = 3 and : [ edit ] Construction The stator co