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Zener diode, 50 W and stock stator, 130 W

Discussion in 'Norton Commando Motorcycles (Classic)' started by APRRSV, Jul 10, 2016.

  1. APRRSV

    APRRSV VIP MEMBER

    Joined:
    Jun 26, 2016
    If the standard single phase stator produces 130 watts and the standard Lucas Zener diode is only capable of sinking 50 watts, Where are 80 watts going when driving without lights and a fully charged battery?
    I couldn't find this particular question answered previously and I apologize if I missed it.

    Ed
     
  2. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Joined:
    Nov 20, 2004
    Old Britts say 130W but most other sources say 120W for the RM21 but maximum output would only be achieved around 5,000 RPM.

    The ignition system takes about 20-30W.
     
  3. Onder

    Onder

    Joined:
    May 11, 2010
    I think the book says that the zener can absorb or turn to heat and have it dissipated the entire output of
    the alternator.
     
  4. Clanger

    Clanger

    Joined:
    Mar 19, 2014
    So Long as the battery is in the system and asuming the ~Zener threshold is around 14.5 volts (maybe more ) then the battery will be absorbing current. If you knew the internal resistance of the battery you could work out roughly how much using good old V=IR. If its fully charged it'll just start making gas.
     

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