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. Output filters in general output filters are used for reducing the voltage stress on the motor windings and the stress on the motor insulation system as well as for decreasing acoustic noise from a frequency controlled motor. Maximum cable length with sine wave filter is 300 m.