European transactions on electrical power vol:10 issue:5 pages:281-286
In the design of rotating electrical machines, the vibro-acoustic behaviour becomes an important criterion. In an electrical machine, electromagnetically induced forces may cause vibrations of for instance, the stator. These vibrations may radiate annoying acoustic energy, especially at resonances of the stator assembly. This paper describes some techniques to analyse the vibro-acoustic behaviour of a (brushless DC-) motor. However; the technique is quite general and cart be used for all types of electrical machines. The "inverse-frequency-response-function" technique (IFRF) allows the identification of the actual vibration behaviour of the motor frame from the measurement of the acoustic field around the motor. Experimental modal analysis yields the resonant behaviour of the motor: A combination of both techniques indicates the critical resonances, causing the undesired acoustic emissions. This may lead to an improved, quieter design of the electrical motor.