Schaffner Sine wave filters

Sine wave filters

Protect the motor against excessive voltage spikes and overheating

Sine wave filters are low pass frequency filters, which convert the rectangular PWM output signal of motor drives into a smooth sine wave voltage with low residual ripple.

Sine wave filters, alternatively called output filters or sinusoidal filters, are mainly used in combination with variable speed drives (VSD) to protect the motor against excessive voltage spikes and overheating. These filters also decrease acoustic switching noise levels and enable longer cable layouts. As a consequence, insulation stress and losses in AC motors are reduced, and therefore prolonging the motor life time.


  • Phases: 1 and 3
  • Current range: up to 5 kA
  • Short circuit current withstand: up to 50 kA
  • Voltage range: up to 36 kV
  • Fundamental frequency: up to 1 kHz
  • Switching frequency: up to 20 kHz
  • Insulation classes: 180 / 200 / 220
  • Protection class: up to IP67 and NEMA 6/6P
  • Cooling methods: AN, AF, WD