Re: Wankels ???


"Trochoidophobic" <flying_booger@xxxxxxxxx> wrote in message
news:1140197181.111872.186770@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Timberwoof wrote:

Horsepower is a mathematical fiction calculated from knowing the torque
output of an engine and the RPM where torque is measured.

Yes, and electrical power is the identical fiction calculated by multiplying
the
number of Coulombs (a large number of electrons) that travel through a wire
each
second (Amperes) by the force carried by each coulomb (Volts). Yea, nobody
believes in watts as the measure of the power of an electrical motor...

Engineers will look at the electric motor's *horsepower* rating in the
manufacturer's catalog whwn selecting a motor, and will use the
kilowatt information to design the wiring that supplies the motor.

Unless they're working in metric units, in which case they'll select the motor
based upon it's kW rating. Both the metric kW and non-metric horsepower are
based upon the motor's rated output. The conductror size is based upon the
input power requried to deliver the rated output kW/horsepower. When you
consider the motor is chosen based upon what it must drive, it makes sense to
rate it by output rather than input.

As I stated previously, Watt needed a comparision for his steam engines
to a known source of power, the muscles of horses. So he had a horse
walk in a circle of a known size, lifting a weight. It managed to
continously lift 550 pounds 1 foot in 1 second.

These guys say -
"Watt determined that a horse could turn a mill wheel 144 times in an hour (or
2.4 times a minute)."
"Others recount that Watt determined that a pony could lift an average 220
pounds 100 feet (30 m) per minute over a four-hour working shift. Watt then
judged a horse was 50% more powerful than a pony and thus arrived at the 33,000
ft·lbf/min figure[5]."

"Engineering in History recounts that John Smeaton initially estimated that a
horse could produce 22,916 foot-pounds per minute. John Desaguliers increased
that to 27,500 foot-pounds per minute. "Watt found by experiment in 1782 that a
'brewery horse' was able to produce 32,400 foot-pounds per minute". James Watt
and Matthew Boulton standardized that figure at 33,000 the next year[6]."

http://en.wikipedia.org/wiki/Horsepower

Not really important, considering not all horses are created equal anyway.

A crude non-angular analogy for the relationship between torque and horsepower
might be that torque equals the Volts, rpm equals Amps, and horsepower equals
Volts times Amps. To continue the analogy, connect a very high resistive load
to a battery and the battery will put out little power because the current (rpm)
is so low. Let the battery rip by using a very small resistance and you'll get
a high current (rpm) with a resultant high power output. Note the
voltage/torque remained unchanged as this is a special battery where voltage
remains constant no matter what load you place upon it.

So, one could connect a 1 volt (low torque) battery, and use a 1/12 ohm resistor
to get 12 amps (high rpm), or 12 watts (horsepower) output.
or -
One could use a 12 volt battery (high torque), and use a 1 ohm resistor to get 1
amp (low rpm), or 12 watts (horsepower) output.

With an engine, torque (and hence power output) can be varied with the throttle.
Changing the torque will also result in a change in rpm, which multiplies the
change in power output because power is torque times rpm. Various aspects of
the engine, such as carburetor, intake, and exhaust, stroke length) can affect
the amount of torque at a given rpm and throttle position, thus resulting in a
wavy rather than linear torque/horsepower versus rpm curve.

Torque is a rotational force, just as voltage is an electromotive force.
Horsepower is a rate of energy usage, as are watts.

Robert


.

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