Engineering Science and Technology, an International Journal (Dec 2022)
A nowel method for measuring inductances and analysis of shaded-pole motors
Abstract
In this paper a novel procedure is presented for precise measurement of inductance parameters and performance analysis of shaded-pole motors, including the effect of space harmonics. It is well known that accurate performance evaluation of electrical machines highly relies on the accurate knowledge of the machine parameters, specifically on the inductance parameters. There is no standard procedure for measuring the inductance parameters of shaded-pole motors due to the presence of the shading coils. In this investigation, for the precise measurement of inductance parameters, an identical motor was produced without shading coils and without rotor bars. Appropriate search coils were inserted into the rotor loops composed of two adjacent rotor slots, and also into the shading-ring slots. A stepper motor with 200 steps was coupled to the motor shaft, and the stepper motor is controlled by a microprocessor. At 200 equally spaced rotor positions over the complete rotor periphery, measurements were taken of the mutual inductance between the rotor loops, mutual inductance between the shading coils and rotor loops, self-inductance of the rotor loops, and mutual inductance between the rotor loops. The stepper motor step angle of 1.8° enabled the 200 steps to cover 360° around the mechanical rotor periphery. For an accurate Fourier series representation of the measured inductances versus the rotor position, the available data points were increased to 3284 using interpolation and the Fourier series coefficients were obtained accordingly. A complete performance of the motor was then modeled and simulated. The input power, input current, and power factor obtained from the simulation were compared with their measured counterparts and a very reasonable agreement was obtained between the two sets.
