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ABSTRACT
As we all know motors find wide application in our day to day life ranging from the house hold appliances to sophisticated industrial equipments. In manufacturing industries like plastic, textile, chemical and pharmaceuticals, speed control of AC and DC motors is important for efficient and consistent production. Various AC/DC drives are available for speed control of these motors. In a number of industries motors must satisfy very strict speed characteristic requirements, both with respect to smoothness of control and also with economical operation. The nature of speed control requirement for an industrial drive depends upon its type. Some drives may require continuous variation in speed for the whole range from zero to full speed, or over a portion , while others require two or more fixed speed. But one has to use separate drives to control AC and DC motors. Here is a circuit that can control the speed of both AC as well as DC motors with variation in speed from zero to full range.