. Electric railway journal . RAM INDI-CATING CONNECTIONS FOR PHASE CONVERTERAND TRACTION MOTORS volt line by the pantograph is fed through an oil-typecircuit breaker to the main transformer. The phase-converter, which changes the single-phase current to thethree-phase form, is connected to the low-tension sideof this transformer, and it operates constantly whenthe engine is in service. To the extended shaft of theconverter are coupled a ventilating blower for themotors and transformers and an air-compressor forthe train brakes, the latter being connected through aclutch. The Phase Converter Th
. Electric railway journal . RAM INDI-CATING CONNECTIONS FOR PHASE CONVERTERAND TRACTION MOTORS volt line by the pantograph is fed through an oil-typecircuit breaker to the main transformer. The phase-converter, which changes the single-phase current to thethree-phase form, is connected to the low-tension sideof this transformer, and it operates constantly whenthe engine is in service. To the extended shaft of theconverter are coupled a ventilating blower for themotors and transformers and an air-compressor forthe train brakes, the latter being connected through aclutch. The Phase Converter The phase converter is a single-phase induction motorwith a short-circuited, squirrel-cage rotor, or secondaryand with two primary windings on the stator. One ofthese windings is connected across the secondary of atransformer, and when the rotor is running there isgenerated in the second winding an emf of 90 deg. phasedisplacement from that of the secondary of the station-ary transformer. The use of this device in railway work. NORFOLK & WESTERN ELECTRIFICATION—MOTORS, GEARSAND JACK SHAFT ON LOCOMOTIVE is so novel that a review of the fundamental principlemay be of interest before the other design details aretaken up. Any polyphase induction motor will operate as asingle-phase motor on one phase of a polyphase circuitif the motor is brought up to its pick-up speed bysome external or internal means. Thus if one wire ofan operating two-phase motor is broken, leaving butone phase in action, it will continue to run. More-over, a voltmeter, applied to the open primary windingwill show a voltage practically equal to that in the linefrom which it was disconnected. The motor is, therefore,performing two functions, motor and phase transformeror converter. The reason why it does so is as follows: Consider first that the motor is operating normallyon the two-phase circuit. The two-phase magnetizingcurrent produces a rotating magnetic field which, cut-ting the secondary conductors (cage-wo
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