Providing optimal motor protection in controlled drive systems, Schaffner's FN5040/45 sinusoidal filters with nominal currents of up to 260A have been recently granted UL-label “cURus” approval. With open design (FN5040) and a housed variant (FN5045 – IP20), they provide user-friendly protection against high voltage edges with large dv/dt-values and over-voltages. The filters smooth the pulse-width modulated output voltage of controlled drive units and provide the motor with a clean sinusoidal voltage with low harmonic content. The filters’ minimum required pulse frequency of 2, 3 or 4kHz can adapted to the standard pulse frequencies of the frequency inverter, eliminating the need to oversize the inverter.