|
Whether it's 5,000 hp or 3,3730 kW, we are talking about its
rated output. Efficiencies, design margins etc. are completely separate
issues.
Duncan
In a
message dated 2001-10-20 11:11:46 Eastern Daylight Time, [EMAIL PROTECTED] writes:
The resistance among mechanical engineers to drop the horsepower
most likely
has a lot to do with the magnitude of numbers. A 5000
HP motor, depending
on how much over design there is in it, can be
"rated" in kilowatts anywhere
from 3 750 to 4 000 kW. In these
cases, the numbers can be rescaled to 3.75
and 4 MW.
The
instinct of a typical mechanical engineer is to just convert the numbers
with a calculator and let the power in watts come out where it does.
But,
you are stuck with a "funny numbers" that twist the tongue.
Also, powers in
watts tend to be numerically less than their
equivalent in horsepowers, thus
the motor doesn't seem to be as
impressive. Mechanical engineers like big
numbers. It
somehow must make up for something else that is lacking. As
for
the power efficiency, the mechanical engineer doesn't care. He turns
that over to the electrical engineer to convert the hp's to watts and
see
how much electrical power is required. As long as the motor
does its job,
they don't care.
And then you get the
idiotic claims on certain household products where, for example, a shop vacuum
says "6.0 peak HP" which would equate to about 4.5 kilowatts which, in turn,
would imply its own dedicated 30 amp, 240 volt circuit! Actual wattage
on the one I have (and the one that makes this claim) is about 900 watts which
would be about 1.2 HP. (The above assumes no losses in conversion of
electricity to mechanical motion, which of course isn't the case.)
Carleton
|
