BRAKE HORSE POWER

[Ed_6]

SORRY IF THIS SOUNDS A BIT IGNORANT. bUT COULD ANYONE SOLVE AN ARGUMENT HAPPENING IN THE OFFICE I WORK IN,



WE ALL KNOW THAT BHP IS THE AMOUNT OF POWER IN AN ENGINE. BUT WHERE DOES THE EXPRESSION BRAKE HORSE POWER COME FROM????????



CAN ANYONE HELP???????

 

[Steveold]

Horse p**n!

 

[DTWD]

I might help if you appologise for typing in capitals.



Paul

 

[Ed_6]

sorry?

 

[RobFenn]

I think in the good ol days they literally said "my car has the power of two horses!" which then must of gone on to be a an actual measurement of some kind, no idea how they meaure it. Or maybe because its pulling power, and thats what horses do/did. Well im havin an arguement with myself now so not much help..sorry!

 

[DTWD]

Ok people, take a deep breath and listen.

One horsepower is 33,000 foot pounds per minute. To find the horsepower of an engine, the torque produced by the engine is measured and the horsepower calculated. This is done using a dynamometer, which is essentially a brake with a measuring device - hence the term brake horse power (bhp).



Hope that clears it all up.



Paul

 

[RobFenn]

lol thats my idea out of the window...but howd you measure torque?

 

[DTWD]

Oh god Rob! I hope your ready for this:



Torque is the twisting force about a point, sometimes called a moment. The torque is defined as the force multiplied by the distance from the pivot perpendicular to the force.

Torque = Force x Distance Perp. to Pivot

For example: One foot pound of torque is the twisting force necessary to support a one pound weight on a weightless horizontal bar, one foot from the pivot. You might directly measure torque when tightening a nut to a specified torque using a torque wrench. Here, a twisting force is applied to the nut, until the resistance to rotation of the nut is equal to the torque required.

Work is the the transfer of energy. The work done is equal to the force applied multiplied by the distance travelled in the direction of that force.

Work = Force x Distance Travelled

Power is the rate of doing work, the amount of work done in a unit of time. The power produced is the work done divided by the time taken.

Force x Distance Travelled
Power = --------------------------
Time

For example: If a weight is fixed solidly to the floor and you try to lift it, you are applying force. However the weight cannot move, so no work is done on the weight. Although force is exerted by your arms, no energy is transferred to the weight. If you lift a one pound weight one foot, then by definition one foot pound of work has been done. If you take one minute to do this then you will be producing power at one foot pound per minute.



There we go, I think that answers it.



Paul

 

[Ed_6]

yes thats all well and good, but that answers part of the question but where does the horse part come into it?

 

[KeithO]

LOL

 

[RobFenn]

jesus christ..ill never be an engineer

 

[viceroy]

Horsepower fast first calculated at how quickly a horse could lift a certain weight (cant remember the weight) through a pulley to the top of a barn.

Cant remember specifics but thats the jist of it

 

[Ben j]

the horse bit came from the earlier ponies

 

[Pysco]

Like Viceroy says its based on how much wieght the average horse can lift, when James Watt started making comercial steam engines he needed something to compare them to, the obvious choice was horses. So he got a bunch of th biggest horses he could find, mesured how much wieght they could lift in a minute and took the average, he then added 20% incase someone had bigger horses than he was testing with and thus was born the horse power.