The magnetic noise of polyphase induction motors

THE WIDE USE of induction motors in the home, the office, and the factory requires that they both look and sound well. The pleasing, if not handsome, appearance of present-day motors attests to the skill of the “appearance design” experts who have worked with motor engineers in recent years. Now, there is a growing demand that motors should have good “sonance design” also. They should give out a steady pleasing hum, just loud enough to show that they are performing their duties properly, but not loud enough to be noticed.