Sinusoidal filter

Sinusoidal filter

Sinusoidal filter – cost savings from using unshielded cables sinusoidal shaped output voltage for your frequency inverter

Advantages of the REO sinusoidal filter:

- Output voltage is sinusoidal
- Also suitable for very long motor cables
- Shielded motor cables are not needed, cost savings of up to €1,800*
- The efficiency level of the entire system will be increased
- Reduction of the motor noise and eddy-current losses

* For more details, please read the following information: REO Performancehighlights

  • CNW 931

    Single-phase sinusoidal filter 6,15% Uk

    CNW 931
    • Nominal Voltage: 230 V
    • Rated current: 3 - 16 A
    • Inductance per strand: 2,8 - 15 mH

    Smoothing of the current and voltage in order to realize long connecting paths.



    • Ambient temperature: 50 °C

    • Protection rating: IP 00

    • Insulation class: F

    • Linearity: LN bei 1,2 x IN u. ≥ 0,8 x LN bei 1,5 x IN

    • Test voltage: 3 kV

    • Rated voltage: 230 V

    • Uk: 6.15 % 

    • Overload category: 2

    • Pollution degree: 2 

    • Cooling: AN

    • Switching frequency: ≥ 4 kHz 

    • Current ripple: ≤ 20 % bei 4 kHz



  • CNW 933

    Three-phase sinusoidal filter

    CNW 933
    • Nominal Voltage: 500 V
    • Rated current: 2 - 1200 A
    • Inductance per strand: 0,05 - 25 mH

    Sinusoidal output current - save costs and trouble-free operation.


    For particularly long cable lengths of > 100m between inverter and motor the shielded cable for EMI suppression used can cause a capacitive coupling. A conventional motor choke can not provide sufficient damping in such cases.


    The sinusoidal filter is a low pass from inductance and capacitance and has a very low resonance frequency. So it is able to generate a largely sinusoidal current. The operation and the loss balance of the asynchronous motor behave like the normal mains operation. The typical motor noise with converter do not occur and a shielded cable to the motor can be dispensed. Losses and heating are greatly minimized and the leakage current will be reduced. Longer motor cable lengths are possible. The motor insulation is protected, thus increasing the service life.


    The sinusoidal filter also attenuates the conducted interference in lower frequency range very good. The losses and the typical noise in the motor plate can be reduced.



    • Rated voltage: U ≤ 3 x 500 V

    • Max. voltage ripple: 5%

    • Field frequency: 0 - 60 Hz

    • Drive switching frequency: up to 150 A >4kHz, from 150 A >1,5KHz

    • Short-circuit voltage Uk: 8% (bei 400V)

    • Voltage drop: 18,4 V/Strang (bei IN und 50Hz)

    • Max. Cable length to the motor: 600 m (unshielded) 1000m (shielded)

    • According to: EN 60289 / EN 61558

    • Test voltage: L-L 2500 V, AC/50Hz 60s; L-PE 2500 V, AC/50Hz 60s

    • Insulation class: T40/F

    • Protection class: IP00

    • Climatic category: DIN IEC 60068-1

    • Overload: 1,5 x INenn 1 min / h

    • Ambient temperature: 40 °C

    • Design: standing on foot angle



    Typical applications



    • Drive systems for motor drives:


      • Mechanical engineering

      • Elevators / escalators

      • Pipes

      • Conveyor technology

      • Ventilation and air conditioning

      • Robotics

      • Automation technology


    • Power supplies

    • Wind turbines

  • CNW 935

    Three-phase sinusoidal Filter

    CNW 935
    • Nominal Voltage: 400 V
    • Rated current: 4 - 24 A
    • Inductance per strand: 2,4 - 12,5 mH

    Sine wave creation of the output current on the output of a frequency drive.Longer lifetime of motor insulation, noise reduction.



    • Test voltage: L-L 1500 V, DC 1 min; L-PE 2500 V, DC 1 min

    • Überlast: 1,5 x INenn 1 min / h

    • Klimakategorie: DIN IEC 60068-1

    • Rotary field frequency: 0- 60 Hz

    • Short circuit voltage Uk: 8% (with 400V)

    • Voltage drop: 18,4 V/branch (with IN and 50Hz)

    • Max. ambient temperature: 40°C

    • Max. voltage ripple: 5%

    • Clock frequency of converter: ≥ 4kHz

    • Max. cable length to the motor: 600 m (shielded) / 1000 m (unshielded)

    • Protection: IP20



  • CNW 961

    Three-phase sinusoidal filter Plus++

    CNW 961
    • Nominal Voltage: 500 V
    • Rated current: 2 - 60 A
    • Inductance per strand: 0,91 - 33,4 mH

    The REO Sinusfilter Plus++ enables to suppress interference not only on line cables to the motor but also to earth conductors.


    The REO Sinusfilter Plus++ also feeds incurring bearing currents into the DC-link so that these may not cause any damage to the mechanics. REO Sinusfilter Plus++ is used in any kind of application which requires safe mechanical continuous power and reliability.


    Examples of such applications are: Water treatment – especially heat pumps – and materials’ safety in general.



    • Conforming to: EN 61558-2-20

    • Test voltage: L-L 1000 V, DC 1 min; L-PE 2500 V, DC 1 min

    • Rated voltage: U = 3 x 500 V

    • Insulation material class: T40/B

    • Climartic category: DIN IEC 60068-1

    • Overload: 1,5 x INenn 1 min / h



  • CNW M 933

    Three-phase sinusoidal filter

    CNW M 933
    • Rated current: 2 - 37 A
    • Inductance per strand: 1,9 - 29,3 mH

    Sinusoidal input current - save costs and trouble-free operation.


    The mains chokes in fully encapsulated version are specially designed for rough environments and offer a very good mechanical protection of the component. The fully encapsulation allows design up to protection ratings IP 66.


    For particularly long cable lengths of > 100m between inverter and motor the shielded cable for EMI suppression used can cause a capacitive coupling. 


    The sinusoidal filter is a low pass from inductance and capacitance and has a very low resonance frequency. So it is able to generate a largely sinusoidal current. The operation and the loss balance of the asynchronous motor behave like the normal mains operation. The typical motor noise with converter do not occur and a shielded cable to the motor can be dispensed. Losses and heating are greatly minimized and the leakage current will be reduced. Longer motor cable lengths are possible. The motor insulation is protected, thus increasing the service life.


    The sinusoidal filter also attenuates the conducted interference in lower frequency range very good. 



    • Rated voltage: U ≤ 3 x 500 V

    • Max. voltage ripple: 5%

    • Field frequency: 0 - 60 Hz

    • Drive switching frequency: up to 150 A >4kHz, from 150 A >1,5KHz

    • Short-circuit voltage Uk: 8% (bei 400V)

    • Voltage drop: 18,4 V/Strang (bei IN und 50Hz)

    • Max. Cable length to the motor: 600 m (unshielded) 1000m (shielded)

    • According to: EN 60289 / EN 61558

    • Test voltage: L-L 2500 V, AC/50Hz 1 min; L-PE 2500 V, AC/50Hz 1 min

    • Insulation class: T40/F

    • Protection class: IP00

    • Climatic category: DIN IEC 60068-1

    • Overload: 1,5 x INenn 1 min / h

    • Ambient temperature: 40 °C

    • Design: standing on foot angle



    Typical applications



    • Drive systems for motor drives:


      • Mechanical engineering

      • Elevators / escalators

      • Pipes

      • Conveyor technology

      • Ventilation and air conditioning

      • Robotics

      • Automation technology


    • Power supplies

    • Wind turbines

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