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Contactor Damping to Eliminate Noise

Discussion in 'Technical' started by kennybobby, Dec 31, 2015.

  1. kennybobby

    kennybobby Member

    Joined:
    Sep 14, 2014
    Messages:
    479
    Location:
    Heart o' Dixie
    TM has a patent application that discusses adding damping to stop the oscillation and squeal noise that can occur during the passage of large DC currents thru contactors. It was thought to be motion of the movable contact relative to the stationary contacts causing the noise. A time history of voltage drop across the stationary contacts shows an audible resonance frequency of ~1.5 kHz:

    contactor_resonance.png

    Several damping solutions were proposed including rubber 0-rings and metal spring friction dampers at the outer edge of the movable contact:

    contactor_friction_damp.png
     

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