The Grundfos Sine wave filters have a high degree of filtering, resulting in a high reduction of the stress on the motor insulation system. At the same time, they reduce the acoustic noise from the motor. Motor losses are reduced due to the fact that a sine-wave filter converts the output pulses of the frequency converter into at sine-wave-shaped. The result is a sine-wave-shaped current and reduced motor noise.

Maximum cable length with a sine-wave filter is 300 m.

They are installed between the Variable Speed Drive and the motor, and are sized dependent on the max. motor running current (amps). Input and output are 3 x 230 volts or 3 x 400 volts, so are suitable for both single and three phase mains power systems. They are typically used on borehole pump applications involving long cable runs.