Danfoss FC 300 Design Manual page 272

FC 300 Design Guide
Options and Accessories
For the FC 300 Series, Danfoss can supply an LC filter to dampen the acoustic motor noise.
The filter reduces the ramp-up time of the voltage, the peak load voltage U and the ripple current
PEAK
∆I to the motor, which means that current and voltage become almost sinusoidal. Consequently, the
acoustic motor noise is reduced to a minimum.
The ripple current in the LC Filter coils, will also cause some noise. Solve the problem by integrating the
filter in a cabinet or similar.
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MG.33.B7.02 - VLT is a registered Danfoss trademark