DC machine teaching experiments

The authors describe a series of three undergraduate laboratory experiments developed at the University of Glasgow. The objectives are: to understand the effect that the drive has on the motor performance; to demonstrate that electric motor design encompasses the fields of electrical, magnetic, thermal and mechanical analysis; and to appreciate open and closed-loop control techniques. A PC based simulation package, PC-DCM, developed for the design of DC commutator motors, is used in the first two experiments. This package is used extensively by members of the SPEED Consortium (Scottish Power Electronics and Electric Drives) in industry. In the first experiment, the student examines the effect that the drive (DC, chopper and phase control) has on the motor performance. In the second experiment, the student calculates the performance of an existing ferrite motor. He/she is then given the task of developing improved ferrite and rare-earth designs, in both cases maximising the torque per unit volume. In the final experiment, a dynamometer is used to study the performance of a DC commutator motor under open- and closed-loop speed control