While the three-phase alternating current traction motor has the advantages of brushless construction and can now offer the potential for regenerative braking, it will not be easy to displace the entrenched direct-current series motor. In the early 1970s UMTA sponsored a test of ac motors on Cleveland Transit after British Railways had operated a similarly equipped locomotive. Both experiments produced successful operation but experienced reliability and complexity problems. Now developments in solid-state components and microprocessor are renewing interest in ac motors for transit and railroads. Europe now has about 200 units in service, primarily involving asynchronous induction motors with the synchronous type used only in France. Canadian Pacific is now testing a 4000-hp diesel with Brown Boveri propulsion system and Amtrak is to retrofit one of its passenger diesel locomotives. UMTA-sponsored Sub-System Technology for Application to Rail Transit (STARS) program has involved two competing ac technologies (Garrett AiResearch and Westinghouse Electric) which will be tested in revenue service on New York City Transit Authority cars. Electromagnetic interference is a major problem for electrical power conditioning systems used to produce variable frequency and modulate currents necessary for ac traction motors.

Media Info

  • Features: Photos;
  • Pagination: 5 p.
  • Serial:

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Filing Info

  • Accession Number: 00399823
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 30 1985 12:00AM