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Hi All...I'm getting mixed signals on the shielding from the ignition switches to a 912 engine. Some say to ground the shields on both ends and some say to only ground them on one end (the engine I assume). Please clear this up for me....Thanks!
  • Re: Ignition Wiring

    by » 9 years ago


    The Installation Manual shows both ends grounded so I would follow that.
    (However; many avionics techs will tell you to only ground one end to avoid a loop)
    So much for clearing it up!

  • Re: Ignition Wiring

    by » 9 years ago


    Ya that's what's confusing. Somewhere there's got to be a contact point for Rotax.

  • Re: Ignition Wiring

    by » 9 years ago


    Hi,

    The shielding wire acts as an antenna and "catches" the radio frequency noises before they get transmitted further. Think of it in terms of radios and antennas.

    You only need it grounded on one end. The amount of current traveling through the shield is minuscule, and by grounding it, you keep it from passing along the signal. Grounding the shielding at multiple points really isn't necessary unless the wire is dozens of feet long.

    On all your grounding connections, I would recommend a protective grease to keep the aluminum grounding point from oxidizing, which can cause lots of headaches later chasing gremlins. This grease is available from Lowes or Home Depot for protecting aluminum house wiring. It's near the large aluminum feed wire in the stores.

    To reduce noise over the radio and intercom, you can install a large capacitor (electrical buffer) on the positive supply wires for those devices. You don't need one rated above 30 volts. The higher the rating, the larger the capacitor will be.

    Kevin
    Sonex Jabiru 3300

  • Re: Ignition Wiring

    by » 9 years ago


    Rotax does not directly comment on the forum, it is only for Owners, but it's in black and white: the Rotax installation manual shows the shield grounded at both ends.

  • Re: Ignition Wiring

    by » 9 years ago


    I think that one side grounding is better.... The best on engine side.
    http://contrails.free.fr/fichiers2/P%20lead.pdf

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