Block Sine Filter SFB-N_400/16.5 – 3 Phase, 16.5Amp 480V

The Block SFB-N 400 series sine filters are designed for use with inverter-driven motor systems to convert pulse-width modulated (PWM) output voltage into a near-sinusoidal waveform. This significantly reduces electrical stress on motors, improves operational performance, and enables reliable operation in demanding industrial environments.

By smoothing the output voltage of frequency converters, the filter helps prevent high dv/dt stress, limits overvoltages at the motor terminals, and reduces insulation strain. This makes it particularly suitable for applications with long motor cable lengths or where motor protection and longevity are critical.

The SFB-N 400 series also contributes to quieter operation by reducing audible motor noise and minimising electromagnetic interference (EMI), helping systems meet stricter environmental and EMC requirements.

These filters are ideal for use in systems where performance, reliability, and motor protection are essential, and can be applied across a wide range of drive-controlled motor applications.

Typical applications include:

• Variable frequency drives (VFDs) and inverter-fed motor systems
• Installations with long motor cable lengths
• Applications requiring reduced motor noise
• Systems sensitive to electromagnetic interference (EMI)
• Industrial environments requiring improved motor lifespan and reliability

Key Benefits

• Converts PWM output into near-sinusoidal motor voltage
• Prevents voltage peaks and protects motor insulation
• Enables longer motor cable runs
• Reduces audible motor noise
• Minimises conducted and radiated interference
• Reduces motor losses and heating
• Improves overall system reliability and lifespan
• Vacuum-impregnated construction for low noise and high corrosion resistance

For optimal performance, the sine filter should be installed between the frequency inverter and motor, and selected according to the drive’s rated current and switching frequency.