NFD Mains Filters

NFD Mains Filters are three-phase input line filters used with DKC drive controllers to reduce conducted interference on the incoming power supply in 50–60 Hz systems. The NFD series supports AC line voltages up to 480 V +10% and is available in multiple rated-current classes so the filter can be matched to the connected drive power level. Maximum continuous current is specified at 45 °C, with defined derating required at higher ambient temperatures. These filters use an IP10 protection category and are rated for operation from DC to 60 Hz at 40 °C. The series also provides short-term overload capability of 1.5 times rated current for 1 minute per hour. Proper installation is critical for safety and EMC performance. The protective conductor must be permanently connected to the filter before startup, and the PE conductor must have a cross section of at least 10 mm² because of the filter’s discharge current. Low-impedance cabinet mounting is also required, including removal of paint at mounting points and use of tooth-lock hardware. The series includes defined insulation and performance limits, including specified dielectric test voltages between line or neutral and protective earth, along with reduced attenuation behavior when high-current saturation occurs.