FUNDAMENTALS OF POLYPHASE ELECTRIC MOTORS推荐.pdf

D FUNDAMENTALS OF POLYPHASE ELECTRIC MOTORS By: Manufacturer of fractional and integral horesepower, AC, Squirrel Cage Motors Totally Enclosed - Drip Proof - Encapsulated D Application Technology Fundamentals of Polyphase Electric Motors INTRODUCTION This bulletin provides basic information on the nature and design of polyphase electric motors. The information is simply presented so extensive engineering or electrical knowledge is not necessary for a good understanding. It is divided into four sections: BASIC MOTOR PRINCIPLES 2 THE AC MOTOR 3 POLYPHASE AC MOTORS 4 Figure 1 SQUIRREL CAGE MOTORS 5-12 HOW A MOTOR WORKS Squirrel cage motors are covered in detail because they are the most common type motor used in industry. Typical The basic principle of all motors can be easily be shown applications include blowers, fans, pumps, compressors, using two electromagnets and a permanent magnet. machine tools, conveyors, mixers, crushers, and industrial Current is passed through coil #1 and coil #2 in such a machinery of all kinds. Basic characteristics are as follows: direction that north and south poles are generated next to the permanent magnet, as shown in Figure 2. A permanent magnet with a north and south pole is the moving part of MAC