Gator's Challenge

[Grumpy Gator]

The challenge is this, please explain the best simple definition of :
Horsepower = Newton Meters. And how that relates to torque.
Please keep it simple.
Jame's Watt came up with "Horse Power" as a marketing tool to sell his improved steam-powered engines more than 100 years ago.
This being an educational forum my thought is we can do better.
**G**
EDIT ...My question was not worded right. Thank You Rzbill for pointing that out.

 

[papa-roe]

That is far above my pay grade.

 

[brav65]

Here is how I increased the horsepower of my truck... obviously I do not understand what torque or horsepower is.

 

[papa-roe]

You have a better grasp than I.

 

[rzbill]

EDITED

That equality is not quite correct.

You have power equal to torque

POWER is a force (F) over a distance (L) per unit time (T) or in other words (FL/T). One HORSEpower is specifically 550 lbs force moved 1 foot in 1 second.
TORQUE is a force (F) times a length (L) or in other words (FL). A Newton is a force and a Meter is a length.

To fix the equation it should be (horse)power = Newton*Meter/sec or FL/T = FL/T

The technique I have shown is called units analysis. The units of measure must be the same on both side of an equation for it to be valid. For this analysis, details of meter vs inch are not important, only that they are both units of length (L)

So...Lets restart. What is it you are trying to ask?? Horsepower conversion to grain*furlong/fortnight perhaps?

See RJs post below for more details.

 

[Grumpy Gator]

Good that's what I'm looking for expand on that
**G**

 

[RJSakowski]

Horsepower is the rate of doing work. Historically, 1 horespower was equivalent to a horse lifting 550 lbs. in 1 sec. and considered the amount of work a horse was capable of on a continuous basis. Work and energy have the same units, i.e. force x distance / time. In the metric system the unit is the joule = 1 newton-meter. In the Imperial system it is the ft.-lb. One joule/sec = 1 watt and 746 watts = 1 hp.

Rotational motion has an equivalent to the linear motion. Torque is a force exerted against a lever arm; force x distance. However even though the units are the same as work, there is a difference which is why you commonly see torque expressed as lb.-ft. in the Imperial system now. The difference is work and power do not have a direction whereas torque does.

A common relationship is made between torque and hp. Torque (in lb. ft.) = hp x 5252 /rpm. The 5252 is an accounting factor arising from the conversion on minutes to seconds and that rotation as expressed as rev./min need to be converted to angular displacement measured in radians with 1 rev. = 2 pi radians.

So.... 1 hp = 550 ft lbs./sec = 746 watts and lb. ft. torque = hp x 5252/rpm. These relationships will fairly well get you through hp and torque

disclaimer: force, distance, and torque all have direction associated with them. It is actually the component along the direction of motion that is effective in doing workso there is a cosine factor as well.

There is an excellent source for learning about things like this called Khan Academy. https://www.khanacademy.org/
Wikipedea also does fairly well as do some of the engineering sites.

 

[rzbill]

OK Grumpy,
Is this a thread about famous Scots??? (Noticed your avatar data)

I worked in the UK for a Scot (funniest man I knew) and travelled to Scotland many times to install milk bottle blowmolding machines in Bellshill for Wiseman Dairies.

 

[Grumpy Gator]

OK I edited my first post.
The challenge still stands. Who's horse? And what does that have to do with power?
I am a wrench and a gearhead. I learned to machine because I wanted better parts built to closer tolerances to go faster.
Every Friday I go to Choir Practice {Car Club} and hear "Horsepower" in every other conversation. ..My answer to that is "Let's go to the track and when the light turns green if you get to the other end before me you win".
Now did you win because of more HP or NM or torque or Watts or joules?
**G**

 

[RJSakowski]

Mr. Watt had come to the realization that there was a need to define power as a means of doing useful work, whether it was pulling up miners and ore in an elevator or turning the grist mill. The horse was the accepted method for portable power. Not being privy to Mr. Watt's experiments, I have no idea as to whether he used a single horse or the average of a number of horses to base his standard.
As to whether torque or horsepower is more important, torque is responsible for acceleration. Zero to sixty requires a lot of torque if you want to keep times down to a few seconds. Horsepower is responsible for maintaining speed in the face of energy losses from friction and air resistance. I have heard it said that a typical car requires around 25 hp. to maintain a 60 mph speed. At racing speeds, air resistance is a major consumer of energy. Torque gets you going and hp keeps you going.
Again, hp, newton-meters, and watts are just different ways of measuring the same thing. Like inches and millimeters and furlongs. A joule is a measure of energy and equals a watt-sec. 3,600,000 of them are a kwh which is equivalent to about $.12 which won't even get you an ounce of beer.