Electric ala Rube Goldberg

Discussion in 'Hybrid' started by Justaguy, Dec 24, 2015.

  1. Justaguy
    Joined: Nov 2015
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    Justaguy Junior Member

    Size and downsides?

    Agree and yes. Makes me wonder though:

    * Can alternators be obtained that are powerful enough to make this anything other than a mechanical novelty?

    * What problems or disadvantages can be anticipated?
     
  2. Yobarnacle
    Joined: Nov 2011
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    Yobarnacle Senior Member

    "The area of the stator times 2 N/cm*cm gives about 20 HP for many alternators. "

    above from my post.

    If you go to that url:

    http://www.rcgroups.com/forums/showthread.php?t=905411

    there's 4 pages of stuff, and one of the posters built an electric motorcycle powered by an altamotor and the speed scared him. Read all about it! :D
     
  3. Justaguy
    Joined: Nov 2015
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    Justaguy Junior Member

    That is encouraging, but it couldn't even begin to make sense to me without an example. Nice to know there's a formula though.

    I went to a related website (from your suggested link), and ended up here:

    www.alternatortechnology.com

    For average, typical car alternators, their data seem to indicate otherwise.

    There are two charts on that page related to power/performance. First one is 84v, which to me seems to be very unusual for a boat. Second is 48v, which makes more sense.

    In the second case (48v), their Chevy Camaro alternator (example) only produced about 1HP at peak.

    Formulas aside, that low power result is what caused me to ask about the conceivable sources of more powerful alternators.
     
  4. Yobarnacle
    Joined: Nov 2011
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    Yobarnacle Senior Member

    The fella built the electric bike was using a motorcycle alternator, from what I induce from his posts.

    The advantage of outrunner motors is the same mechanical advantage you have with a screwdriver.
    The large handgrip allows multiplying torque on the smaller diameter screw.
    The OUTSIDE casing of the outrunner motor spins, not the internal parts normally called the rotor. The internal parts are a stator on an outrunner.

    Just think of the outrunner as a screwdriver with large diameter handle, compared to the normal inrunner with a small diameter handle.

    If both types ran at same speed, the outrunner develops more torque. More torque at same rpm =more horsepower.

    Here's a calculator you can plug in some numbers and see for yourself.

    http://ncalculators.com/electrical/torque-to-horsepower-calculator.htm


    Also volts X amps = watts and 745 watts = 1 horsepower.
    The posters in the url I recommended, were talking 200 volts at 100 amps.
    That's 20,000 watts or 20 kilowatts. Divided by 745 watts = 26.8 horsepower.
     

  5. freddyj
    Joined: Oct 2013
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    Location: kansas

    freddyj Senior Member

    Why not use an electric motor for propulsion plus a belt to drive an alternator so the batteries always stay charged? That way you get the best of both worlds and don't have to carry any fuel! LOL
     
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