DC & AC Motors and Drives....The Great Debate, 1999 Polymers, Laminations & Coatings Conference Proceedings

Joseph P. Abraham

Senior Controls Engineer

Black Clawson Converting Machinery LLC

Fulton, NY 13069

The purpose of this paper is to introduce the reader to the basic differences between DC & AC motors, drives, and complete systems through use of an in-depth comparison of the two technologies. It is intended to help the reader to better understand the differences between DC & AC and to give a better understanding of the advantages and disadvantages of each. It should help to clear up any confusion that you may have about each and guide you in making an educated selection of one technology or the other. It is assumed that the reader has a general understanding of both DC & AC motors and drives. Although all data is deemed to be accurate, the values stated are not necessarily true for all manufacturers. They are, however, a very good generalization of the high-end drive products available today. As a general note, unless otherwise stated, the use of the term DC motor refers to a standard shunt wound DC motor that is drip-proof blower ventilated (DPBV). The term DC drive refers to a 3-phase, 6-pulse, fully regenerative, digital DC drive. The term AC motor refers to an AC inverter-duty (or vector duty) induction motor. The term AC drive refers to a 3-phase, digital, closed loop, AC Vector (or torque controlled)

drive.