Date of Award

Spring 2004

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Electrical and Computer Engineering

First Advisor

Demerdash, Nabeel A. O.

Second Advisor

Yaz, Edwin E.

Third Advisor

Povinelli, Richard J.


Starting of induction machines cause torque transients, high inrush currents, and thus heating of the machine. A popular method for starting an induction machine is applying electronically controlled soft starting voltages using series connected silicon controlled rectifiers (SCRs). A flux linkage ABC-frame of reference model of a soft started three-phase induction motor was implemented. A state-space model of the soft starter thyristor switching sequence for the motor and load was developed and implemented in a time-domain simulation to examine heating issues for different starting profiles. Simulation results of line starts and soft starts are compared with measured data through which validation of the model is established. In this thesis, different induction machine soft start profiles are shown and comparisons of starting times, torque profiles, and heating are made. Discussion of these results and conclusions as to the nearest to optimum types of profiles are delineated based on severity of torque oscillations, peak torque, starting times, and winding heating criteria.



Restricted Access Item

Having trouble?