Moleykutty George

EDDY CURRENTS IN SOLID RECTANGULAR CORES

An expression for the eddy current loss in solid rectangular cores is obtained using linear electromagnetic field analysis. Wherefrom text book formula for eddy current loss is derived highlighting various assumptions involved. To get an insight into the current interruption phenomena, electromagnetic fields in a composite rectangular core are analyzed. It is concluded that the reduction in eddy current loss in a laminated cores is basically due to the insertion of distributed capacitors in eddy current paths. Presence of these capacitors increases the impedance of the eddy current path, reducing eddy currents and eddy current loss.

EDDY CURRENTS IN LAMINATED RECTANGULAR CORES

A simplified expression for the eddy current loss in laminated rectangular core is obtained using linear electromagnetic field analysis. The treatment takes cognizance of current interruption phenomena, by considering capacitive effects of insulation regions. Analysis presented in this paper assumes identical field distribution in each lamination and ignores eddy currents in insulation regions.

Model reference controlled separately excited DC motor

This research article proposes the speed control of a separately excited DC motor (SEDM) in the constant torque region. The novelty of this article lies in the application of artificial neural network-based model reference controller (MRC) for the speed control of SEDM. This paper also discusses and compares the speed control systems of SEDM using PI-controlled and fuzzy logic-controlled chopper circuit with MRC. The entire system has been modeled using MATLAB 7.0/SIMULINK toolbox. It has been observed that chopper-controlled speed control system could be eliminated by the use of MRC and the performance of the proposed system is comparable with speed control system using chopper circuit.

New functionality of active power line conditioning system

This manuscript proposes the effectiveness of active power line conditioning (APLC) system to deliver short circuit current whenever a shunt fault occurs at the load side. One may note that if the APLC system is able to deliver short circuit current then unnecessary interruption of main power supply could be eliminated. The developed APLC system is able to achieve balanced sinusoidal source currents in phase with respective source voltages even under short circuit conditions. The method assumes that under short circuit conditions, the ac power supply is allowed to carry rated current. The APLC system implemented in this manuscript uses a separate dc power supply rather than the dc capacitor.

Augmented Short-Circuit Test for the Measurement of Transformer Equivalent-Circuit Parameters with Large Series Branch Impedances

An augmented short-circuit test is described for the determination of equivalent-circuit parameters of single-phase transformers with large series-branch impedances. This test may be conducted at rated currents with the transformer connected to a reduced voltage supply. Thus harmonics in current and voltage waves are negligible. This test is therefore free from harmonics-associated errors. Based on test results, phasor equations are found which give formulae for the equivalent-circuit parameters with series-branch impedance split into low- and high-voltage components.