where does the power go?

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Will
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Re: where does the power go?

Post by Will » Mon Sep 19, 2005 3:17 pm

Torque is the factor from which all HP is derived- wihtout torque there is no HP equation to derive any work from !-
The product of a force and distance is torque !
746 Watts of potential is the "same as " or "equal to " 550 pounds feet of potential (Stored) energy) ! -
What absolute bloody nonsense ! There is absolutely no point in trying to make anyone, who would publish such utterly ridiculous BS, in the errors of their ways.
For the rest/some of who may be confused as to the meaning of it all. British mechanical engineers (Who probably know little about mechanical engineering but invented the Watts steam engine, the railway locomotive and the steam turbine) use ft.lbf to distinguish energy or work and lbf.ft to indicate torque. For instance 3.0 lbf.ft means a 3.0 lbf force applied at a radius of 1.0 ft - or - a force of 1.5 lbf applied at a radius of 2.0 ft - or - what ever you like as long as the product of the two is 3.0 lbf.ft
Horsepower is defined as force*distance per minute/33,000 = FD/(33,000*t) OR 2.pi.T.N/33,000
where T is the torque in lbf.ft and N = rpm. (Not RPMs) so torque is F*R (Force*radius) so that if we were looking at a belt travelling over a pulley of radius R then the belt distance travelled in one minute would be 2.pi.R.N the force at the periphery of the pulley would be that in the belt so that 2.pi.T.N = 2.pi.F.R.N = F.2.pi.R.N = FD i.e both equations equate. It is a fact that out of three features of horsepower i.e. HP, Torque and rpm. If any two of them are defined for an application then the third is irrevocably fixed.
A blonde was sitting in a railway carriage reading a newspaper and came across an article which stated that ' 12 Brazilian soldiers had been killed in an action ' So she nudged the guy next to her and asked " Excuse me - how many is a Brazilian ?"
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Will
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Re: where does the power go?

Post by Will » Mon Sep 19, 2005 3:33 pm

Typos again ! For " in the errors of their ways " read ' see the errors of their ways "
Forgotten point - furlong.stones per fortnight is OK with me - One furlong.stone per fortnight is, in fact, exactly equivalent to 1/720,000 horsepower i.e. one one seven hundred and twenty thousandth part of a horse power. One furlong (long furrow) - (Originally an acre was the area of land which could be ploughed (plowed ?) in one day by a team (pair?) of oxen. and, in that analogy, the plot of land measured one furlong (220 yards) long by one chain (22 yards)
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Chris Smith
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Re: where does the power go?

Post by Chris Smith » Mon Sep 19, 2005 5:27 pm

Will, I can see why you don’t have your degree in mechanical engineering. Your still trying to argue with history, and win. My teacher who was a Scott, made it a imperative that we learn the difference between the ignorant wanna bee engineer, and what his fellow Scot distinguished as the Torque and HP factors. <p>Hey, you don’t have a degree so you not really obliged to get it right, and your one for one there.<p> Keep arguing with the history book and physics books, perhaps their silence has you thinking your wining? <p>Its still Pounds feet where foot pound has no “standard” for measuring its total but torque and HP Do. <p>And a potential, is still just a potential, and not actual work done. <p>Your post shows why we have standards, but no one said you have to follow them, and you obviously dont.

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Re: where does the power go?

Post by josmith » Mon Sep 19, 2005 7:35 pm

My professor was unable to speak the day we learned about touque.He was a little horse. When I asked him a question his brow went into a long furrow and he answered in foot pounds.
Now that's horsepower
Sorry just pulling your chain!

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Chris Smith
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Re: where does the power go?

Post by Chris Smith » Mon Sep 19, 2005 8:20 pm

Furlongs do make up Rods and chains, so I guess they can also make up a long lever? <p>But then the rod and chain, were a surveyors tools.<p>It could be said, we "Perched" on a "Pole" to gain 5-1/2 yards of leverage?<p>[ September 19, 2005: Message edited by: Chris Smith ]</p>

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Re: where does the power go?

Post by rshayes » Tue Sep 20, 2005 4:54 am

"Will, I can see why you don?t have your degree in mechanical engineering. Your still trying to argue with history, and win. My teacher who was a Scott, made it a imperative that we learn the difference between the ignorant wanna bee engineer, and what his fellow Scot distinguished as the Torque and HP factors. <p>Hey, you don?t have a degree so you not really obliged to get it right, and your one for one there."<p>This is a typical Chris Smith post. As you can see, everyone else is ignorant of Physics and History and Chris is the Keeper of the Sacred Flame.<p>He has no knowledge of Will's educational background and yet he is stating as an absolute fact that Will does not have a degree. This is unjustified and unprofessional.<p>Will happens to be correct. Chris has shown by his posts that he does not understand the physical concepts of work and energy at this time. He could have learned them 35 years ago and have forgotton them in the interim. It is certainly a possibility, since I have known electrical engineers that have forgotten how to use Ohm's Law over a similar period of time.

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Re: where does the power go?

Post by terri » Tue Sep 20, 2005 6:41 am

I knew somebody would figure out the HP equivalent of stone-furlong per fortnight for me! Thanks, Will!<p>So far, it seems to me that <p>3 x 6 .NE. 6 x 3, according to one faction.<p>and,<p>3 x 6 = 6 x 3, according to the other faction.<p>Doesn't this involve the Law of Commutation in arithmetic?<p>Well, at least we agree on the denominator....<p>[ September 20, 2005: Message edited by: terri ]</p>
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philba
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Re: where does the power go?

Post by philba » Tue Sep 20, 2005 10:47 am

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by stephen:

...
This is a typical Chris Smith post. As you can see, everyone else is ignorant of Physics and History and Chris is the Keeper of the Sacred Flame.
...
<hr></blockquote><p>While, in general, I don't think we should personalize posts like this, I have to say that in this case it is justified. Chris makes it his business to let people know how stupid and ignorant he thinks they are. <p>It seems like when ever there is a thread that he makes several posts to, it degenerates into a long winded, pedantic and philosophical discussion which serves mainly to give Chris a soap-box forum to denigrate the credentials of others? He makes many inflammatory posts that seem designed to troll up arguments. He generally "wins" the argument by outtyping and outlasting the others. Repetio-ad-nauseum. <p>I am personally against moderation but it is threads like this that make me reconsider.<p>Well, have a nice day!
Phil<p>[ September 20, 2005: Message edited by: philba ]</p>

terri
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Re: where does the power go?

Post by terri » Tue Sep 20, 2005 11:44 am

"They...use ft.lbf to distinguish energy or work and lbf.ft to indicate torque."<p>Okay, now I got it. It's merely a convention to distinguish between the two --and the "pound-feet" torque is static, meaning a turning or twisting force which is not applied through a distance.<p>I can torque the head bolts on my engine to 75 pound-feet, and maintain that torque without any further motion of the bolt heads for any given time without expending any power since there's no further motion. <p>In this instance, there's no motion, only a torque.<p>So that we call "pound-feet."<p>But if I have a motor that delivers that much torque through a (rotary) distance, then we can measure the power output by dividing this torque through a distance by the time involved.<p>In this case, there's motion involved, so it's not just a torque, it's a torque through a distance.<p>And this we can now call "foot-pounds."<p>And the measure of power for linear distances is the same, foot-pounds per time interval.<p>Ahhhh, now I get it. Thanks, guys.<p>[ September 20, 2005: Message edited by: terri ]</p>
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Chris Smith
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Re: where does the power go?

Post by Chris Smith » Tue Sep 20, 2005 12:22 pm

Lets have a show of hands. <p>Who has their mechanical engineering degrees, and who is just playing with them self? <p>Google doesn’t pass out degrees, so no false showings there please. <p>I laugh, as I did my exams, passed my tests with these exact answers, and got a higher score than those like you who wanna bee revisionists and pseudo engineers. <p>Good luck, your still wrong. <p>And how do you tell an engineer from a wanna bee? <p>Just read those answers above, it tells the story of who sat for the exams, and who didn’t. <p>Sorry, but your google bluff is worthless and incomplete.

rshayes
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Re: where does the power go?

Post by rshayes » Tue Sep 20, 2005 1:54 pm

Energy is represented by the application of force over a distance.<p>In the case of rotation, the force is called torque, and, using the convention described by Mr. Nailen on page 2 of this thread, the English unit would be the "pound-foot". The unit of distance would be the "radian".<p>For linear motion:<p>1 horsepower = 550 foot-pounds per second<p>For rotation:<p>1 horsepower = 550 pound-foot-radians per second<p>The purpose of this convention appears to be to provide a method of distinguishing the type of motion from the units used. This convention is also consistent with the unit conversion tables in the reference books that I have.

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Re: where does the power go?

Post by Will » Tue Sep 20, 2005 1:57 pm

...passed his tests . . . What language can the tests have been in if they didn't require some proficiency in use of the English language ?.
. . furlongs do make up rods and chains . . . Nonsense 4 rods (5.5 yards) = one chain (22yards) = one furlong (220 yards) Do not rods and chains make up furlongs ?
Graham - You are of course right - he is unprofessional - that's understandable - he isn't a professional. <p>Phil - I agree with you Don't be too hard on him - he may quit and then I won't be able to enjoy his contributions.

Terri - no problems - just to verify it - One furlong = 660 feet, one stone = 14 lbf, one fortnight = 14 days = 336 hours = 20,160 minutes - One furlong.stone/fortnight = 660*14/(20,160*33000) = 1/72000 horse power. Also . . .You summed up the ft.lbf/lbf.ft (energy/torque) conundrum adequately and succintly. Well done<p>[This (my) last word on ft.lbf] The Columbia Encyclopedia 6th Ed June 2005
. . . "pound.foot . . . . See foot.pound"
The Columbia Encyclopedia . .
" foot.pound . . customary unit of work or energy in the English Gravitational system of units."
Websters New World Dictionary January 1988 " foot.pound.sec . . . British, Canadian and US system of units ."<p> Hands up! I don't have a degree in mechanical engineering - and I'm a real engineer.
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Re: where does the power go?

Post by terri » Tue Sep 20, 2005 2:04 pm

"1 horsepower = 550 pound-foot-radians per second"<p>I'm at work on a long-overdue and well-deserved break, so maybe I'm not thinking straight, but shouldn't there be a (2 x pi) in there somewhere?<p>Coffee! Me need coffee! Gimme coffee! NOW!<p>(Thanks for the acknowledgement, Will!)<p>[ September 20, 2005: Message edited by: terri ]</p>
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josmith
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Re: where does the power go?

Post by josmith » Tue Sep 20, 2005 3:16 pm

The two pi is already in there. If you have a one foot radius the circumference is 2pi feet. A circle has 2 pi radians so one radian would equal one foot of circumference. It's exactly the same as the linear version. 550 pounds of force at one foot per second.

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Re: where does the power go?

Post by rshayes » Tue Sep 20, 2005 3:25 pm

The radian has the factor of 2 pi in it.<p>1 revolution is 2 pi radians.<p>Using radians as a measurement for angle can simplify the algebra considerably in some cases, especially differentiating and integrating sines and cosines.<p>It also makes the equations for rotational problems similar to those for translational problems.

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