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Motor Efficiency Improvement Experiments

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1999 Annual Conference


Charlotte, North Carolina

Publication Date

June 20, 1999

Start Date

June 20, 1999

End Date

June 23, 1999



Page Count


Page Numbers

4.390.1 - 4.390.16

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Paper Authors

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Donald V. Richardson

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

Session 2633


Donald V. Richardson, Emeritus Waterbury State Technical College, Connecticut



This paper describes experiments developed while teaching in the former Waterbury State Technical College. It show how all experiments, however performed, have the same seven fundamental steps. Two things are demonstrated: That original work can be done in a two year school, and to both encourage teachers and professors and ex- plain how original experiments can be performed.

These DC motor experiments, scaled up to diesel electric locomotive traction motors, proved able to clarify and resolve problems known to manufacturers and the AAR (As- sociation of American Railroads) but were unable to explain. The AC experiments show potential efficiency improvements not yet covered in the literature.

I. Introduction Electric motor fundamentals go back to the pioneering experiments of Michael Fara- day, who discovered that a conductor carrying current, when immersed in a magnetic field, produced a lateral force. All motors (and generators) whether AC or DC use this principle, regardless of their specific size or configuration.

DC motors need some form of synchronized current switching to reverse current in the rotor coils as they pass though a magnetic field which reverses at least once per revolu- tion. Traditionally this switching has been done by a rotating metallic commutator and stationary brushes. The commutator is a segmented copper cylinder which sequentially offers access, one coil at a time, to carbon “brushes” which transfer current to that coil, forming a rotating switch.

Only in the past decade or so, have various solid state devices replaced this commuta- tor + brushes package to dynamically route current to/from the optimum rotor coil for smaller motors.

Richardson, D. V. (1999, June), Motor Efficiency Improvement Experiments Paper presented at 1999 Annual Conference, Charlotte, North Carolina.

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