FC 300 Design GuideFC 300 Selection" IP 21/IP 4X/ TYPE 1 (NEMA 1) Enclosure KitIP 20/IP 4X top/ TYPE 1 (NEMA 1) is an optional enclosure element available for IP 20 Compact units.If the enclosure kit is used, an IP 20 unit is upgraded to comply with enclosure IP 21/ 4X top/TYPE 1 (NEMA 1).The IP 4X top can be applied to all standard IP 20 FC 30X variants." IP 21/Type 1 Enclosure KitA - Top coverB - BrimC - Base partD - Base coverE - Screw(s)Place the top cover as shown. If an A or B option isused the brim must be fitted to cover the top inlet.Place the base part C at the bottom of the drive anduse the clamps from the accessory bag to correctlyfasten the cables. Holes for cable glands:Size A2: 2x PG16 (Ω") 3xPG21 (3/4")Size A3: 3xPG16 (Ω") 3xPG21 (3/4")" LC FiltersWhen a motor is controlled by an adjustable frequency drive, resonance noise will be heard fromthe motor. This noise, which is the result of the design of the motor, arises every time an inverterswitch in the adjustable frequency drive is activated. The frequency of the resonance noise thuscorresponds to the switching frequency of the adjustable frequency drive.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 UPEAK and the ripplecurrent ∆I 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 LC filter coils will also cause some noise. Solve the problemby integrating the filter in a cabinet or similar.82 MG.33.B6.22 - VLT is a registered Danfoss trademark
