Product Description:

The NFD04.1-440-120 mains filter is a passive, cabinet-mounted component produced by Bosch Rexroth Indramat for the NFD Mains Filters series. Positioned on the incoming side of frequency converters, servo drives, and other power electronics, it attenuates conducted interference that would otherwise propagate along supply conductors or be reflected back into the plant network. By inserting low-impedance paths for high-frequency energy while preserving the fundamental power waveform, the device supports stable operation of sensitive automation equipment on busy production lines.

Designed for switchboards energized at a nominal line potential of 440 V AC, the filter channels all conductors through an LC network rated for 120 A of continuous current. Its balanced architecture serves a three-phase system, keeping differential voltages equal and minimizing neutral displacement. The filter meets electromagnetic compatibility category Class A, which limits conducted emissions to levels acceptable in professional and industrial locations. The inductors present high impedance to fast dV/dt edges created by switching inverters, while the capacitors return common-mode noise to ground, preventing malfunctions in adjacent control circuitry.

The topology also remains effective when the feeder drifts toward an alternate supply of 460 V AC, and internal clearances withstand a line-to-neutral potential of 265 V AC without dielectric stress. As a line filter, it provides broadband insertion loss that complements the active suppression functions inside drive inverters, reducing harmonic feedback into utility transformers. The NFD Mains Filters series uses consistent mechanical dimensions and terminal layouts across current ratings. Engineered for industrial service, the assembly tolerates elevated ambient electrical noise, frequent motor starts, and the thermal cycling typical of automated production environments.