Re: Mobile S-Rotor!


"TomGee" <lvlus@xxxxxxxxxxx> wrote in message
news:1133992847.677395.71000@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> K. Jones wrote:
>> "TomGee" <lvlus@xxxxxxxxxxx> wrote in message
<snip>
>> Couple of points.
>>
>> 1. Car alternators don't use nearly as much horsepower as you think, and
>> the
>> belt-pully power transmission is far more efficient than any wind
>> turbine.
>> Most cars have between a 35 amp to 65 amp alternator......12 volts * 65
>> amps
>> = 780 watts 1 HP = 746 watts. Even a heavy-duty 100amp alternator is
>> less
>> than 2HP, and that's at full draw.
>>
>>
> I don't know where you're getting your information, but the hp
> requirements from the vehicle engine to turn the alternator have always
> been set at 15 hp and above. The smallest estimate I could find was 4
> hp. Most large vehicles don't use the puny car units, they use up to
> 250 amp alternators. My device uses belts and pulleys too so how could
> it be any less efficient?

250A x 12V = 3000 watts. If the alternator is only 75% efficient, then the
engine must supply 4000 watts to drive that alternator under full load.
4000 watts is only about 5 hp.

>>
>>
>> Vehicle alternators run at much less
>> than max capacity most of the time. Even if it could work (it can't),
>> who
>> is going to put a light-bar sized box on the roof of thier car for about
>> 1
>> HP difference? You'd never be able to tell the difference.
>>
>>
> I wouldn't and neither would you. It is true that alternators run at
> much less than max capacity most of the time, that's why the actual
> average hp usage to turn the alternator is hard to pin down on any
> vehicle. Transportation industry vehicles are more likely to run their
> alts at higher than average automobile capacity. It is more
> cost-efficient to use an alt that loafs along most of the time and only
> occasionally achieves max power. That's not the point. If my rotor
> saves gas - which I at first hoped would amount to about 1.5 to 2.0%
> fuel usage, has only one moving part, and has a ROI of within a year,
> the transportation industry should quickly see they all must use it to
> remain competitive, and as a taxpayer, I would insist that all govmint
> vehicles use it.

I would insist that your device pass some clinical trials before burdening
the tax payers with this idea.

>>
>>
>> 2. There is no "energy" from the wind flowing over the car, unless the
>> car
>> is not moving (parked). You have to imagine the car moving through
>> essentially stationary air, like a boat travelling through stationary
>> water.
>>
>>
> I know it sounds counter-intuitive, but it works both ways. We can say
> that the car moves through the wind at 60 mph or that the wind moves
> around the car at 60 mph. I thought the same thing at first, so my
> first test of my first model was to see if there really was power in
> the wind created by a moving vehicle. Holding the rotor out the window
> while my van was driven from a stop to 55 mph, its rpm increased
> proportional to the van's increase in speed. At 55 mph, it was turning
> at 70 rpm, and that sure surprised me! Your no. 2 is wrong as my test
> shows that there is indeed energy in the wind created by a moving
> vehicle.

70 RPM, but at what torque?? Developed power is speed times torque. If you
can stop your device with one hand, then the torque is probably pretty low
and the overall power low.
<snip>
>>
>> Energy has to be expended to push the vehicle through the air, to push
>> the
>> turbine through the air. As the turbine is less than 100% efficient, it
>> will always take more HP to push the turbine through the air, than can be
>> extracted from the turbine.
>>
>>
> That's fine so long as the hp required is still less than the vehicle
> engines requires to turn it own alternator. My calculations show that
> it takes about 1 to 2 hp for the vehicle engine to push my rotor box
> than it takes for it to turn its own alternator, which is from 4 to 30
> hp.

But if your box only adds 1 to 2 hp to the vehicle engine demand, it cannot
develop more than 1/2 to 1 hp output. So it couldn't drive even a 100 amp
alternator. Can't get out more than you put in.

Your device would convert engine power in the form of drag, to mechanical
power at no better than the Betz limit (and probably a lot less), so you're
already down to 59% of the power from the engine. A belt driving an
ordinary alternator is much higher than that.

daestrom


.

Relevant Pages

  • Re: Emergency power system for one perosn: Generator or battery system?
    ... for power are smaller and require more portability than ... well gee, check the amp specs of a modern vehicles alternator, likely ... An Rv gen is not a car gen, its heavy duty vs my economy thing. ... Northern Tool has a cheap chinese 1000w gen that has a very good ...
    (alt.home.repair)
  • Re: OT: 2008 Pontiac G6 GXP
    ... A lot of it also has to do with the driver. ... that your car had the racing ECU. ... Now onto this battery and alternator issue. ... Your alternator DOES NOT supply power sirectly to your car. ...
    (rec.gambling.poker)
  • Re: Mobile S-Rotor!
    ... >> requirements from the vehicle engine to turn the alternator have always ... Most large vehicles don't use the puny car units, ... > engine must supply 4000 watts to drive that alternator under full load. ... Developed power is speed times torque. ...
    (sci.energy)
  • Re: Switch Your Engine Off When In A Queue
    ... car that's been sat in full sun for a while. ... power needed? ... Cutting the compressor in and out. ... I could supply a link to a large PDF entitled "Impact of Vehicle ...
    (uk.rec.cars.misc)
  • Re: Mobile S-Rotor!
    ... Car alternators don't use nearly as much horsepower as you think, ... >> requirements from the vehicle engine to turn the alternator have always ... > engine must supply 4000 watts to drive that alternator under full load. ... >> occasionally achieves max power. ...
    (sci.energy)