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What is meant by the term: "beat frequencies" ? If you work in a place with lots of machines, you have probably felt or heard one. Have you ever walked by a machine and felt or heard the vibration increasing . . . and then going away . . . and then increasing . . . and then going away . . . etc., etc. That is a "Beat" vibration. |
Beat vibrations are caused by vibrations that have very close to the same period and similar amplitudes. |
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What does this interaction of these signals produce ? |
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For example, a 2-pole US motor is running at, say, 3580 rpm. Line frequency is 3600 cpm. The difference is 20 cpm. That means if the 1x rpm component and the line frequency component have similar amplitudes, there will be a beat frequency occurring at 20 cpm. If you have ever walked past a motor and heard it "humming", it is a beat vibration being generated by the interaction of mechanical and electrical frequencies. |