UK and Europe · Public discussion

New front wheel

Started by Martin Dann · · Last activity · 2 posts · 425 views

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UK and Europe
Published
4 October 2005
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4 October 2005
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Martin Dann
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  1. Just took my new front wheel out for a spin (well about 10pm).
    It is the first and only wheel that I have built myself.

    Down Pempbroke road (Bristol) around the triangle, all the way up
    whiteladies road and blackboy hill (to see how well it works and
    slow speeds, and how well the light works). Then back down white
    ladies at speed to make sure the bulb does not blow at speed.
    Then back up white ladies road and home.

    Did I mention it has a dynohub, with black spokes. (big grin).
    With a cateye dual daylight lamp unit, using only one bulb.
    (The second bulb is also 3W so that I can use it as a spare).

    It is nice and bright with a 3W 39p prefocus bulb, I will be getting
    halagons soon.

    Anyway it is a shimano hub with a smart switch.

    What is in the smart switch, is it just a light sensor, or does it provide
    over-voltage protection?. If I wanted to wire both bulbs in series, would
    I have to loose the smart switch? (with zeners wire across the individual
    lamps).

    I currently have a dpdt switch on the lamp unit, and would like to wire
    the switch so that in one position both are on, and in the other two
    positions either one or the other lamps are lit. I presume it is safe
    to short the lamp I want turned off.

    Martin.

    --
    Typed by monkey #27662472869676 on typewriter #7552416572242
    When emailing me, please include the word Banana in the subject line.

  2. "Martin Dann" <[email hidden]> wrote in message
    news:[email hidden]...

    Quoted message said:

    Anyway it is a shimano hub with a smart switch.

    What is in the smart switch, is it just a light sensor, or does it provide
    over-voltage protection?. If I wanted to wire both bulbs in series, would
    I have to loose the smart switch? (with zeners wire across the individual
    lamps).

    Yes, the smart switch voltage regulates.

    One choice is to lose the smart switch.

    Another is to wire your second lamp, the one with the shorting switch, in
    series between the dynamo and the input to the switch. Well, it works for me
    with 2v of LED lamp, so I think it should work - I've not actually tried it.
    There's a little bit of current flowing when it's switched off (though only
    one of the phases), so I'd leave it in shorted out mode if the other is
    switched off.

    If you do this, the second won't need overvoltage protection - the main +
    switch means you don't need to.

    Quoted message said:

    I currently have a dpdt switch on the lamp unit, and would like to wire
    the switch so that in one position both are on, and in the other two
    positions either one or the other lamps are lit. I presume it is safe
    to short the lamp I want turned off.

    If you're keeping the shimano switch, leave that to take care of the main
    lamp. Wire the other with a shorting switch.

    I wouldn't bother trying to treat both lamps equally - accept that one is
    the full time one, and the other is the extra when you're going fast enough.
    In the advent of a blown bulb in the full time one, nick the bulb from the
    extra and short that lamp out. Bulb blowing is sufficiently rare IME that
    devising a switching circuit to save yourself a bulb change on the road
    isn't worth it.

    Also you probably don't want to have a switching setup such that you can
    short both out.

    cheers,
    clive

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