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Jumper Cables?

Discussion in 'Gen 2 Prius Main Forum' started by exces6, Dec 3, 2004.

  1. bruceha_2000

    bruceha_2000 Senior Member

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    Which brings up a question. Can one of you technical people tell me why the motors are AC not DC? Seems it would be more efficient to not have the losses inherent in converting back and forth. And if I remember, DC is less dangerous and less complicated than AC.
     
  2. jayman

    jayman Senior Member

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    Frank, those sort of horror stories are much more common now thanks to electronic fuel injection. At the very least, you could cook a factory radio if left on: most owner manuals warn the radio must be off.

    I still believe in being a Good Samaratin but not if you have bad things happen too. If my Canadian Tire booster box happens to cook, I'm only out $80.
     
  3. cnetter

    cnetter New Member

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    Jayman,

    How big is you booster box? Does it hold a charge if left alone (in the car) for extended periods of time? (ya I could look all this on online, but I'm too busy or lazy right now. ;-) )

    It sould like a nice thing to have and I could still make the crack about the matter/anti-matter drive.

    Chris
     
  4. DanMan32

    DanMan32 Senior Member

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    As far as the dangers, the so-called AC is travelling short distances: from the inverter, to the motors below it.

    As generators, MG1 & 2 provide sinusoidal 3 phase AC. That's just the nature of a fixed coil and permenent magnetic rotor.

    As motors, I see them more as 6 stage stepper motors. Any one of the legs can be connected to either pole of the 500V DC, and either of the remaining 2 connected to the remaining pole. Its AC, because the field currents change direction, but it is more of a square wave; its either on, or off. There are other power controls that regulate how much of that 500V is given to the motor's phase switching circuit, and I believe that is by pulse width modulation.

    I believe John's site has a link describing motor drivers using switching circuitry.
     
  5. DanMan32

    DanMan32 Senior Member

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    By the way, I want to thank all of you on this thread for reminding me about the risks of boosting someone. A close friend of mine wanted my jumper cables and car to start his girlfriend's car. I offered to charge the battery, but not boost it for starting.
    We decided to wait for her get home with his car and boost her car with his car and my cables.
     
  6. jayman

    jayman Senior Member

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    Thanks for replying, I actually remembered my booster box under the desk. It's now fully charged for next time.

    As far as physical size, slightly deeper than a large 2-slice toaster and around 25 lbs (I'm guessing on the weight). It's rated for 700 A. The Book Of Instructions claims it can be left 3 months before recharge, but I think I'll check it every month to be sure.
     
  7. Sufferin' Prius Envy

    Sufferin' Prius Envy Platinum Member

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    <div class='quotetop'>QUOTE(bruceha_2000\";p=\"56481)</div>
    It is true that DC current is less dangerous to the human body, but DC can also kill and is much harder to manipulate.

    The major advantage that AC electricity has over DC is that AC voltages can be very easily transformed to higher or lower voltages. Transforming to higher voltages - 500,000 volts for interstate transmission lines - allows power to be transported economically due to the reduced amperages and wire sizes required.

    Electricity is created either when a wire is moved through a magnetic field or when a magnetic field is moved past a wire. The nature of AC current is such that its electro-magnetic field - which expands and contracts with every pulse of the AC cycle - can induce an electric current into nearby wires . . . no need for moving parts! DC on the other hand has a electro-magnetic field that is constant, except for during the rise or fall of voltage. (Alternating Voltage anyone? :pukeright: )

    For the Prii, it is the voltage transformation and lower amperage properties that count. For you, keeping your fingers away from the orange wires will help. :wink: