Sine-Wave Filters - Danfoss FC 300 Design Manual

8. Options and Accessories
8.1.17. IP 21/Type 1 Enclosure Kit
A – Top cover
B – Brim
C – Base part
D – Base cover
E – Screw(s)
Place the top cover as shown. If an A
or B option is used, the brim must be
fitted to cover the top inlet. Place the
base part C at the bottom of the drive
and use the clamps from the accessory
bag to correctly fasten the cables.
Holes for cable glands:
Size A2: 2x M25 and 3xM32
Size A3: 3xM25 and 3xM32

8.1.18. Sine-wave Filters

8
When a motor is controlled by an adjustable frequency drive, resonance noise will be heard from
the motor. This noise, which is the result of the design of the motor, arises every time an inverter
switch in the adjustable frequency drive is activated. The frequency of the resonance noise thus
corresponds to the switching frequency of the adjustable frequency drive.
For the FC 300 Series, Danfoss can supply a sine-wave filter to dampen the acoustic motor noise.
The filter reduces the ramp-up time of the voltage, the peak load voltage U
current ΔI to the motor, which means that current and voltage become almost sinusoidal. The
acoustic motor noise is thus reduced to a minimum.
The ripple current in the sine-wave filter coils will also cause some noise. Solve the problem by
integrating the filter in a cabinet or the like.
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MG.33.B9.22 - VLT ® is a registered Danfoss trademark.
FC 300 Design Guide
and the ripple
PEAK