Smooth starting of slip ring induction motors

• Published in: IEEE transactions on energy conversion Vol. 12; no. 4; pp. 317 - 322
• Main Authors: Abdel-Halim, M.A., Badr, M.A., Alolah, A.I.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.12.1997; Institute of Electrical and Electronics Engineers
• Subjects: A.c. Machines; Applied sciences; Capacitance; Constraint optimization; Electrical engineering. Electrical power engineering; Electrical machines; Equivalent circuits; Exact sciences and technology; Frequency domain analysis; Inductance; Induction motors; Mathematical model; Rotors; Torque control; Wounds; Three phase machine; Minimum time; Induction machine; Starting; Optimization method; Unsteady state; Time curve; Electric motor; Wound rotor machine; Slip ring machine; Modeling; Electrical impedance
• ISSN: 0885-8969
• DOI: 10.1109/60.638867

The starting of three-phase wound rotor induction motors by stepped resistances added in the rotor circuit suffers from several problems. This paper suggests a novel method of motor starting by inserting a parallel combination of resistance, inductance and capacitance in the rotor circuit. The proposed method guarantees a smooth and high starting torque over most of the starting period besides a controlled starting current. A mathematical model is developed based on a frequency domain quasi-steady state equivalent circuit. An optimization technique is then applied to determine the values of the rotor added elements such that minimum starting time is achieved subject to current and torque constraints. Experimental verification has been carried out and the computed results are in good agreement with the measured values.