The Impact of Variable Frequency Drives (Frequency Inverters) (part 8)
Continued from this article: The Impact of Variable Frequency Drives (Frequency Inverters) (part 7).
We know acoustical motor noise is one of drawbacks of applying variable speed drives (AC drives). This is one main concern why some engineers are not willing to use the drives. Below we will go deep on this disadvantage of the drive.
In some installations, placing a variable speed drive (VSD, VFD) on a motor increases the motor's acoustical noise level.
The motor noise occurs when the drive's non-sinusoidal (current and voltage) waveforms produce vibration in the motor's laminations. The non-sinusoidal current and voltage waveforms produced by the variable frequency drive (VSD, VFD, AC drive) are the result of the transistor switching frequency and modulation in the DC-to-AC inverter. The switching (or carrier) frequency may be a fixed value or (in new technologies) a variable value. The value of the carrier frequency determines the audible motor noise.
A factorin the excitation of a motor's laminations is how closely the drive (frequency inverter) approximates a pure sine-wave. (to be continued)
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You may be interested in reading this: Applications Considerations While Appling Frequency Inverter (VFD)
Know more about VFD technology: Overview of variable frequency drive technology
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