RZS Sinusoidal Filters

RZS Sinusoidal Filters are three-phase LC output filters used between a frequency converter and motor to smooth the converter’s pulsed output into a more sinusoidal motor-side waveform. This filtering helps reduce voltage peaks, insulation stress, cable interference, and additional motor losses, making the series useful in installations with long motor leads, parallel motor-line arrangements, or higher EMC requirements. RZS filters are available for 380–400 VAC and 500 VAC class systems, with maximum output-frequency limits of 200 Hz for 380–400 V applications and 100 Hz for 500 V applications. Total connected motor-cable length can reach up to 400 m depending on the installation, although shielded cable reduces the allowable length. Proper application requires the converter to operate at a pulse frequency of at least 8 kHz, the motor current to remain within the filter’s rated current, and the system design to account for the filter’s small load-dependent voltage drop.