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jim rozen
 
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Default Compressor Motor: HP v.s. Amps?

In article , Gary Coffman says...

That's not what the definition of work says, though.


Oh now I see your point. The pendulum trades energy between
kinetic and potential. When it is speeding up one could say
that the gravitational force is doing 'work' on the ball.
When slowing down, the ball gives energy back into the
gravitational potential - 'negative work.'

That's right, in a perfect system that's all lossless,
but the term 'work' still applies.

Jim

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Robert Salasidis
 
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Default Compressor Motor: HP v.s. Amps?

On Tue, 14 Oct 2003 03:45:32 -0400, Gary Coffman
wrote:

The disagreement is mostly that one can use the explanation of
automotive torque vs RPM or Volts vs Amps as a good way to explain
power (in case someone has trouble visualizing the concept)



On Mon, 13 Oct 2003 22:17:29 -0400, Robert Salasidis wrote:
I would disagree - as foir a given horsepower motor, the PSI vs the
CFM is the determinant of the HP.


So what are you disagreeing about?

Gary

Therefore one can achieve a greater PSI at a lower CFM and vise versa.

The same applies to car engines - the Torque x RPM = HP

(One can say Volt x Amps = Watts follows the same rules.)

In th case of design - many variables would come into play - such as
torque vs RPM curves - which are different depending on the type of
motor/engine in question

On Fri, 10 Oct 2003 13:22:30 -0400, Gary Coffman
wrote:
On Wed, 08 Oct 2003 23:15:31 -0400, Robert Salasidis wrote:
Would it be accurate in the case of the compressor to say that torque
would be related to the PSI that can be produced, and HP would relate
to the airflow (cfm) at that PSI.

No, not in the general case. Depending on the design, you can trade
between pressure and flow in a fairly arbitrary manner, same as you
can trade between RPM and torque to get power.

It is true that for a given piston head area, crank throw, etc, maximum
pressure will be torque limited, and volume will be RPM limited. But you
can't say that either is proportional to either in a general sense away
from the limit cases.

Gary


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