Re: relay help req. (horsepower definitions)

Ballendo,
Methinks that either you are messing with our minds or
this is a test to see who's sleeping at the switch ;-)
Your carefully worded query "What rules of math did I break?"
is the tipoff. There is nothing wrong with your arithmetic
but you did bend the rules of logic and the laws of physics.
First, the torque was not measured, but calculated from the
desired 1.5 HP result. The final calculation is just a way
of verifying the first calc. and provides no new information.
Second, your efficiency (the ratio of power output to power
input) for the router is 1.5/1.233 or 121 percent. For the
Leeson motor it's a much more believeable 1.5/2.536 or
about 60 percent. My old physics book says that the
efficiency of any machine is always less than 100 percent...
I enjoy and read all of your posts, but you did "ask" and I
couldn't keep from jumping in.<g>
Keep it up!
Al

--- In CAD_CAM_EDM_DRO@egroups.com, ballendo@y... wrote:
>
> So you're saying that my 115V,8A, 1.5hp(claimed),25k rpm Black and
> Decker model 3315 router does not compare to the motor at:
>
> http://www.oneida-air.com/1_5hp.htm
>
> Which shows: Motor Specs-Leeson Industrial 1.5 HP Motor 110v/220v
> 17.2/8.6 amps 1.15 service factor
>
> Because Obviously 8A does not equal 17.2A! And Watts are obtained
> from the 'PIE' equation: Power(Watts) = I(Amps) x(times) E(Volts,
or
> electromotive force)
>
> Router: 115 x 8= 920 watts Leeson motor: 110 x 17.2= 1892
watts
>
> Using 746 watts equal one horsepower:
>
> Router: 920/746= 1.233HP Leeson motor: 1892/746= 2.536HP
>
> Why is the leeson motor rated only 1.5 HP??? Because of the two
> things I've left out so far: RPM! and torque!
>
> Let's use the mechanically derived 'rotating' HP definition:
> hp = torque X rpm X 1/5252
>
> BTW (.0001904 is 'about' 1/5252) and T= torque
>
> Router: 1.5hp= ???T x 25000rpm x .0001904 simplifies to:
> 1.5/4.76 = .315 torque
>
> Leeson motor: 1.5hp= ???T x 1725rpm x .0001904 simplifies to:
> 1.5/.32844 = 4.567 torque or (2.283 torque using 3450 as the rpm.
> we'll ignore the 3450 rpm model since it simplifies directly to the
> 1725 model)
>
> Now let's see if these two motors HP agree:
>
> Router: .315 torque at 25000 rpm is 7875
> Leeson motor : 4.567 torque at 1725 rpm is 7878
>
> This is MUCH closer than the 746 Watts based example!!!
What 'rules
> of math' did I break???
>