Does HP matter?

   / Does HP matter? #141  
As someone who puts his nose into pure mathematics for a while, I can say that pure mathematicans live in another world. You can call that they belittle pure physicans and even applied mathematicans. Pure mathematicans are really in another worlds. just to give an example. For physicans, there is only one infinity. For a pure mathematican, there are infitine number of infinities. But, they do somethings real even though they themselves are not aware of what they do really and they communicate with physicans and applied mathematicans about what they are doing really, their means in the real life, etc. Sometimes, especially in last decades, big inventions (such as Einstein's general relativity, black holes, etc which are not proved physically yet) were made in pure mathematics first. Anyway, pure mathematicans are in another worlds and the gap between them and common people has increased a lot. But, this is a reason for a pure mathematican to be proud. Common should actually thank a little to physic and applied mathematicans who try to make common understand things in science and mathematics more. That's why we see different expressions of power, force, etc etc. due to their efforts of physic and applied math people, not pure mathematicans at all who live in a world they have built for themselves.

Anyway, maybe, a new math teaching way is really necessary, maybe, should be started at the beginning. Till 2-3 decades ago, there were philosophy courses at high school, now, which are omitted. For example, without understanding what the force is, we are memorizing it and errors in our understanding are getting bigger in later stages like snowballs. For example, we often said here that force is a static thing. What an average Joe understands from this when it is called static? He'll probably understand that there is no motion. Right, engineers too understand same. But, no motion ideally means timeless, infinitely same state in time. Again, ok. But, then, we should not see "time" in its unit of force then if it is same in "all time". Now, lets look at the unit of force (in si unit system.) It is N, that's, Newton. Now, we don't see time here. See how we are forced to forget its background, hidden time in this unit.. Lets rewrite it explicitly. N = Kg x m / s / s. (here, m/s/s or m/s^2 as you know is unit of change of velocity, or, acceleration.) So, we use time even for a force on a body which always sits on the ground. We say this force is constant, and we call it weight. This is so because of our one assumption we make in our early schools, that's, gravitational acceleration is constant, which is not actually, changes a little depending on its coordinates in the world vertically and horizontally. This is another story, but, I am trying to come to a point.

If you looked into our talks here, what thing an average Joe noticed? He probably noticed that whenever we divide a quantity by time, we called it power. So, in my words above about the force, now, he noticed that another quantity too is divided by time and he probably thought that force too is power. Technically and mathematically, correct according to grouping math method. Actually, now, saying force is power isn't a strange expression for his logic of any Joe who hasn't seen any school in his life. Now, let me give another example to tell him what we technicans call a power rather than telling him what the power really is.. When you see a man keeping a big rock in his hands above his shoulders and stays so, what do we say? What a powerful man! Well, this was in very old days, centuries ago, in pre-engineering life. Today, correct expression is "strong man", not powerful man. To call him hercule or powerful man, we technics look at "how fast" he lifted the rock up above his shoulders, which means there is "time" in ranking. This is why today we divide quantities by time to call the output as power. So, power in old days was like a static concept while today it requires a dynamic to have a power. But, even at Newton's times, 5 century ago, we forget there is a hidden "time" even in static force like gravitational force, weight. People at Newton's time were understandable as they didn't know gravitational acceleration isn't constant actually. But, although we learn it in early school days, we forget our early assumptions, neglecting things like change in gravitational accelerations which is indeed small. But, forgetting this assumption make us lose our base, and errors in technique accumulate in further stages of educations and communication language gap between average Joe and engineers gets bigger and miscommunications happen a lot. But, engineers should be respected more, even more than pure mathematicans who try to pull engineers toward themselves and they open the gap more. Engineers are like middle-men, who are blamed or critisized more than others, so, because they are close to average Joe. Average Joe critisizes engineers not by telling things to him clearly. On the other end side, pure mathematican critisizes engineer for his low level of science, and them pure mathematicans even belittle them engineers, even physicans and applied mathematicans. Average Joe living in a "very real" life and pure mathematican Joe living in totally another world out of totally real life should have a meeting and lets see what these two lazies can do about what engineers couldn't.
:thumbsup: ! :confused2: ... Well, it occurs to me that you might be able to explain the term G^2/Hz used in random vibration. Can you do it real? It would be useful to my mind.
larry
 
   / Does HP matter? #142  
You guys are insufferable :D I know this. It takes all kinds for what we do on this earth from those crazy ladies who run day care to the men who control our debris. I appreciate everyone and their varied brain builds. For anyone to look down anyone's nose whether it be a mathematician, a quantum scientist or a chimney sweep either doing so to each other or otherwise aren't taking full advantage and benefit of the world around them. Thank you for your input. Its been a combination of pleasure and teeth pulling.
 
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   / Does HP matter? #143  
More is always better than never enough go for something around 10 HP more than what you think you will need in the long run you will be glad you did !!!!
 
   / Does HP matter? #144  
:thumbsup: ! :confused2: ... Well, it occurs to me that you might be able to explain the term G^2/Hz used in random vibration. Can you do it real? It would be useful to my mind.
larry

Larry, you are pulling my legs into the mud I been in before (my thesis was about chaos though not statistically or stochastically, but, from deterministic and analytic point of view.)

Let me guess, you are an engineer and in electronics, who you have worked or been working in electronic filters too. Averaging experimental or real data and to try to simplify works of filters by trying to find some simpler analitical formulas to reduce freedom dimension in chaotic signals. Raw data is mathematically in discrete group. I was in other side, searching chaotic behaviours in deterministic, analytical, continuous groups which is more strange to even high experts of physicans and applied mathematicans. Anyway, I wasn't in stochastic deeply, but, will try to interpreate G^2/Hz (but, in a language with average Joes can understand without their running their minds which are not reserved for such things.)

G^2: Lets not talk about this much as this is a stochastic quantity which won't be easy for anyone who is totally foreigner to stochastic quantities. Lets call it Root Mean Square of a quantity which physicans called it acceleration. (mathematicans call quantities without physical meanings while physicans try to name quantities by connecting them to some real, known, things. It is not acceleration (change in velocity) actually that common know. But, physicans prefer to use acceleration for any "change of change of a quantity" even if quantity isn't length, ft.. Square root of square of a quantity is for averaging reason as wave goes up (positive) and down (negative) sides of an axis, so to find absolute values. By averaging, and hence, grouping, actually, symmetries are searched in random vibrations so to simplify/reduce the freedom dimension of chaos or seem-to-be random motions. Pressumptions there such as lapping simple periodic waves over each others many times. Finding such simple symmetries or periodic waves in random waves will reduce dimensions of freedom and degree of randomness will reduce, so that with less effort (computation or measurement), data can be analysed. Anyway, lets stay with name "a stochastic quantity" about G. (I guess, the intention here is not questioning what G is, but, its dividing by frequency, Hz.)

Frequency, that's, Hz. that's, "cycle per second." It is a quantity in the same group with RPM as both are 1/time.

G, a stochastic quantity, per "cycle per time" is called somethings like "power" in stochastic field and you are asking this because it is confusing people as it is not "per time", but, "per cycle/time." As I said, it is due to Physicans who like to use "known" physical quantity names for somethings new quantites per somethings. In wave field, people prefer to use things per cycles such as energy per cycle, etc or even "per cycle per time" which is frequency so to simplify/reduce their dependent variables, so, to play with less number of equations.

Ok, this is becoming an advanced topic for average Joes who are probably asking even what the wave is. (not belittleing anyone here, but, this question is like doing an advanced math) Who can explain what the wave is to a man who has lived in a cave or a small village for his whole life, without attending even elementary school? This seem-to-be easy question is actually a hard question even for high educated people. Since this is public, what I was trying to do in my posts above is to try to tell things in such a language that everybody in public can understand. (I'd like to explain what the wave, periodic wave, random wave, etc by using a simple wheel on a road, but, anyway, not here now as we are really going off-topic.)
 
   / Does HP matter? #145  
Larry, you are pulling my legs into the mud I been in before (my thesis was about chaos though not statistically or stochastically, but, from deterministic and analytic point of view.)

Let me guess, you are an engineer and in electronics, who you have worked or been working in electronic filters too. Averaging experimental or real data and to try to simplify works of filters by trying to find some simpler analitical formulas to reduce freedom dimension in chaotic signals. Raw data is mathematically in discrete group. I was in other side, searching chaotic behaviours in deterministic, analytical, continuous groups which is more strange to even high experts of physicans and applied mathematicans. Anyway, I wasn't in stochastic deeply, but, will try to interpreate G^2/Hz (but, in a language with average Joes can understand without their running their minds which are not reserved for such things.)

G^2: Lets not talk about this much as this is a stochastic quantity which won't be easy for anyone who is totally foreigner to stochastic quantities. Lets call it Root Mean Square of a quantity which physicans called it acceleration. (mathematicans call quantities without physical meanings while physicans try to name quantities by connecting them to some real, known, things. It is not acceleration (change in velocity) actually that common know. But, physicans prefer to use acceleration for any "change of change of a quantity" even if quantity isn't length, ft.. Square root of square of a quantity is for averaging reason as wave goes up (positive) and down (negative) sides of an axis, so to find absolute values. By averaging, and hence, grouping, actually, symmetries are searched in random vibrations so to simplify/reduce the freedom dimension of chaos or seem-to-be random motions. Pressumptions there such as lapping simple periodic waves over each others many times. Finding such simple symmetries or periodic waves in random waves will reduce dimensions of freedom and degree of randomness will reduce, so that with less effort (computation or measurement), data can be analysed. Anyway, lets stay with name "a stochastic quantity" about G. (I guess, the intention here is not questioning what G is, but, its dividing by frequency, Hz.)

Frequency, that's, Hz. that's, "cycle per second." It is a quantity in the same group with RPM as both are 1/time.


G, a stochastic quantity, per "cycle per time" is called somethings like "power" in stochastic field and you are asking this because it is confusing people as it is not "per time", but, "per cycle/time." As I said, it is due to Physicans who like to use "known" physical quantity names for somethings new quantites per somethings. In wave field, people prefer to use things per cycles such as energy per cycle, etc or even "per cycle per time" which is frequency so to simplify/reduce their dependent variables, so, to play with less number of equations.

Ok, this is becoming an advanced topic for average Joes who are probably asking even what the wave is. (not belittleing anyone here, but, this question is like doing an advanced math) Who can explain what the wave is to a man who has lived in a cave or a small village for his whole life, without attending even elementary school? This seem-to-be easy question is actually a hard question even for high educated people. Since this is public, what I was trying to do in my posts above is to try to tell things in such a language that everybody in public can understand. (I'd like to explain what the wave, periodic wave, random wave, etc by using a simple wheel on a road, but, anyway, not here now as we are really going off-topic.)



Power spectral density (PSD) analyzers generallly express the ordinate as Energy/hz with frequency as the absissa, as i recalll (but my recollection is to good! grin).
 
   / Does HP matter? #146  
Returning back to original topic "does hp matters really",

HP you are given (in specs section of catalogue) usually is about the engine, not the pto.
Whether it is car or tractor or whatever, there is the gear chain system (gearbox) between engine and work-maker end (tyres or pto.). Gearbox decides how much of HP will be converted to Torque and how much to Speed. In cars, most of HP is converted to Speed while mostly to Torque in work-maker vehicles like tractors. (remember HP is a multiplication of Torque and Speed. So, HP is constant for an engine while its torque and speed can be changed by gear systems.) If Torques of 2 vehicles with different HPs are SAME, then, bigger HP vehicle will do the same work faster, but, won't be able to do heavier work, that's it.
 
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   / Does HP matter? #147  
If Torques of 2 vehicles with different HPs are SAME, then, bigger HP vehicle will do the same work faster, but, won't be able to do heavier work, that's it.

That is exactally what I have been preaching all along.:thumbsup:
 
   / Does HP matter? #148  
That is exactally what I have been preaching all along.:thumbsup:

If we are talking about torque and HP available at the wheel, I agree. If we are talking at the engine, I must know the gearing available. If the gearing is identical, I agree so long as "won't be able to do heavier work" means "won't be able to do heavier work than the other vehicle."
 
   / Does HP matter? #149  
I got an email asking this (I believe there are some other people too who are asking same things.)

Someone wrote:
".... If Torques of 2 vehicles with different HPs are SAME, then, bigger HP vehicle will do the same work faster, but, won't be able to do heavier work, that's it.

Torques are same in given portion. HPs are different in given portion. The Bigger HP vehicle doing the work faster is implied by the HP being larger with same torque. But how is it known this vehicle cannot do heavier work? It was given equal torque and higher power..."

---------

Maybe, because of my English (my 2nd language) - maybe, because of technical issues (2nd language of people foreigner to technical terms) - people might be confused about my sentence above and may say "how comes! bigger power must do heavier work! and Nomad, you are wrong.."

Let me make it clear.

HP is power of engine. You divide it to portions: Torque work and Speed work. Remember again Power = Torque x Speed...

Torque does the work at pto, that's, a portion of engine power is used at pto as torque is to make the work there at pto. So, through gears in gearbox, lets say 90% of engine power is used at pto, 5% is used to carry the weight of tractor and 5% is reserved for Speed of tractor. (figures i say here are just arbitrary.)

Lets say we have 2 tractors: one has 100 hp engine and the other has 110 hp engine.. But, with SAME torques at their pto's.. (this was the question in original post.) Lets say 90 hp of each of these tractors are reserved for their pto torques. Then, tractor with 100 hp engine will use 10 hp for speed while tractor with 110 hp can use 20 hp for speed - and this means, 110 hp tractor can run faster while doing the same MAXIMUM amount of work at its pto.. Pto torque is given as rated or maximum pto torque. So, since their torques, peak / rated / maximum torques, are same, even higher HP engine tractor won't make heavier work - but, tractor movement will be faster. However, if you change gearbox of higher hp tractor, then, of course, you can have bigger torque at bigger hp tractor, but, then its faster speed will reduce.

This is most important formula for the relation between power and torque:

Power (HP) = Torque (lf.ft) x Speed (Rpm) x Some Constant

(forget about this "some constant", not so important, changes depending on the units (second, hour, etc) you use..) Play with this formula, by keeping torque as constant or speed as constant, etc. my words in paragraph above will be clear then.
 
   / Does HP matter? #150  
If we are talking about torque and HP available at the wheel, I agree. If we are talking at the engine, I must know the gearing available. If the gearing is identical, I agree so long as "won't be able to do heavier work" means "won't be able to do heavier work than the other vehicle."

Powers, HPs, in question are engine powers. Torques (same) mentioned here in first post is PTO torques. Therefore, gearing is NOT identical, gear ratios are different, hence, torques of different HPs are same at ptos. So, output power hp at pto is same since both pto have same rpm, 540, and torques are same, though their engine hps are different.
 
   / Does HP matter? #151  
After 15 pages, I think, confusions are clear now. Some people are talking about engine HP while some others are taking it as PTO power.. When talking only about PTO Power, Bota and some other people taking HP as PTO HP are correct. Of course, Same torque at pto and same speed (540 rpm) will give Same HP at PTO (using equation above.)
 
   / Does HP matter? #152  
Powers, HPs, in question are engine powers. Torques (same) mentioned here in first post is PTO torques. Therefore, gearing is NOT identical, gear ratios are different, hence, torques of different HPs are same at ptos. So, output power hp at pto is same since both pto have same rpm, 540, and torques are same, though their engine hps are different.

I had no idea that the torque mentioned was at the PTO while the HP mentioned was at the engine. I am used to seeing PTO HP mentioned and engine HP and Torque mentioned, but never the PTO torque. Live and learn, I reckon.
 
   / Does HP matter? #153  
I had no idea that the torque mentioned was at the PTO while the HP mentioned was at the engine. I am used to seeing PTO HP mentioned and engine HP and Torque mentioned, but never the PTO torque. Live and learn, I reckon.

At the first post, this wasn't clear. Torque in first post was engine torque? I believe farmers usually use pto torque rather than engine torque which is looked at by car owners.. In general, everybody (car, tractor, etc owners) takes HP as engine HP and this is normal as it is rated power that engine machine can give from combustion in cylinders in which pistons follow linear motion. We mention torque only about rotating parts from crankshaft to gears to transmission shaft to pto (for tractors) at end side. So, when engine torque is mentioned, it is the torque at the crankshaft actually, measured torque after energy or power losses in combustion and at bearings of crankshaft. When there is no pto, like in cars, it is usual to talk about engine torque which is actually crankshaft torque. At any rotating part, we can mention hp too as it is torque and speed multiplication. Since hp, usually engine hp, is constant for an engine, in general, engine hp is meant when hp is mentioned.. In cars, usually torque is not mentioned, but its max speed (unless it is off-road car.) So, depending of application of engine/vehicle, torque at different points become important and in farm field, it is pto torque is important if attachment is driven by pto.. So, I got the torque in first post as torque at pto. If not, if it was engine torques which are equal while hps are different, then, it is another story, related to engine itself, more about crankshaft, flywheel speed and tyre wheels. In this case, bigger hp vehicle will run faster or vehicle itself is made heavier to spend extra hp to carry its extra weight. Anyway, I believe farmers usually use pto torque rather than engine or crankshaft or flywheel torque which is more important for, say, off-road cars.

PS: Farmers here in Turkey usually use only power, HP when talking about tractors. I have seen here on this forum mostly US farmers participate that the torque is frequently in discussions. While including torque in talks causes confusions, it is a reason for progressing in learning and clarifications.
 
   / Does HP matter? #154  
At the first post, this wasn't clear. Torque in first post was engine torque? I believe farmers usually use pto torque rather than engine torque which is looked at by car owners.. In general, everybody (car, tractor, etc owners) takes HP as engine HP and this is normal as it is rated power that engine machine can give from combustion in cylinders in which pistons follow linear motion. We mention torque only about rotating parts from crankshaft to gears to transmission shaft to pto (for tractors) at end side. So, when engine torque is mentioned, it is the torque at the crankshaft actually, measured torque after energy or power losses in combustion and at bearings of crankshaft. When there is no pto, like in cars, it is usual to talk about engine torque which is actually crankshaft torque. At any rotating part, we can mention hp too as it is torque and speed multiplication. Since hp, usually engine hp, is constant for an engine, in general, engine hp is meant when hp is mentioned.. In cars, usually torque is not mentioned, but its max speed (unless it is off-road car.) So, depending of application of engine/vehicle, torque at different points become important and in farm field, it is pto torque is important if attachment is driven by pto.. So, I got the torque in first post as torque at pto. If not, if it was engine torques which are equal while hps are different, then, it is another story, related to engine itself, more about crankshaft, flywheel speed and tyre wheels. In this case, bigger hp vehicle will run faster or vehicle itself is made heavier to spend extra hp to carry its extra weight. Anyway, I believe farmers usually use pto torque rather than engine or crankshaft or flywheel torque which is more important for, say, off-road cars.

PS: Farmers here in Turkey usually use only power, HP when talking about tractors. I have seen here on this forum mostly US farmers participate that the torque is frequently in discussions. While including torque in talks causes confusions, it is a reason for progressing in learning and clarifications.

I tend to be more like the farmers in Turkey. I mostly consider engine HP, and PTO HP, and then hydraulic flow and pressure.

Thanks for the reply. Your English is quite good. I would be thrilled to speak a second language as fluently as you. I studied French, but I never was very fluent.
 
   / Does HP matter? #155  
Thanks for the reply. Your English is quite good. I would be thrilled to speak a second language as fluently as you. I studied French, but I never was very fluent.

Well, people here in general can't speak any second language, especially farmers not at all. I am a university graduate, furthermore, had worked in an international research center in Europe for a year. But, my English is rather technical as you might see rather than dailylife, county-life English. However, when hanging around farm forums for conversation with farmers, I gained some more than technical English which is not well spoken of course even by people whose native language is English. In that sense, I am beyond educated engineers too. But, this is not different in Turkey or anywhere else, farmers in turkey are not so familiar to technical Turkish too. By the way, I had learnt a some French too and German, quite easy after English as these languages are similar to each others, in the same language family, Indo-Euro language family. Turkish is Altaic language which can be very difficult to learn for an English, French, German and so on while it is much more easier for a Japan as it too is in Altaic language family. Anyway, this is going OT. These things we talk here particularly in this thread is a Technical language rather than the languages we speak in daily life. Btw, you Americans need to use SI (metric) more than British unit system which is causing a lot of confusions in international communications. No, I am used to lb-ft system too well, but, ordinary people of the world are having troubles.
 
   / Does HP matter? #156  
Btw, you Americans need to use SI (metric) more than British unit system which is causing a lot of confusions in international communications.

Oh how I wish America would go completely SI (a.k.a. metric). I grew up using our crazy imperial system, and I'm used to it; but that doesn't mean I like it.
 
   / Does HP matter? #157  
Returning back to original topic "does hp matters really",

HP you are given (in specs section of catalogue) usually is about the engine, not the pto.
Whether it is car or tractor or whatever, there is the gear chain system (gearbox) between engine and work-maker end (tyres or pto.). Gearbox decides how much of HP will be converted to Torque and how much to Speed. In cars, most of HP is converted to Speed while mostly to Torque in work-maker vehicles like tractors. (remember HP is a multiplication of Torque and Speed. So, HP is constant for an engine while its torque and speed can be changed by gear systems.) If Torques of 2 vehicles with different HPs are SAME, then, bigger HP vehicle will do the same work faster, but, won't be able to do heavier work, that's it.
Wow. Theres some inexact reference to parameters. Mechanical HP transmitted by rotation includes torque. Torque is amplified via mechanical advantage. Inherent in that is a loss of speed. There is no conversion.
larry
 
   / Does HP matter? #158  
Oh how I wish America would go completely SI (a.k.a. metric). I grew up using our crazy imperial system, and I'm used to it; but that doesn't mean I like it.

I know that the metric system makes a lot more sense. But there are times when it is totally inadequate. 4th down and centimeters just doesn't cut it for me. :D
 
   / Does HP matter? #159  
Yea, or go to the lumber yard and ask for a 2.5m 5x10........(8' 2x4):laughing:
 
   / Does HP matter? #160  
Wow. Theres some inexact reference to parameters. Mechanical HP transmitted by rotation includes torque. Torque is amplified via mechanical advantage. Inherent in that is a loss of speed. There is no conversion.
larry

True, it is not really a conversion. I tried to explain "Power = Torque x Speed" literally and conversion isn't correct word. From the equation, as seen, for a constant power, the more torque the less speed and the vice versa. This was what I meant.

I know that the metric system makes a lot more sense. But there are times when it is totally inadequate. 4th down and centimeters just doesn't cut it for me. :D

Here, this expression is totally foreign to me, "4th down and centimeters just doesn't cut it.." ?

Brits have been resisting against SI metric system which is much more easier in learning and use, because of their long archy rival-ism against France. But, although SI was born in France, it was just a location, not brought to the world by French scholars, but, by international scholars.

Anyway, I am used to British unit system too, but, am an educated person. I rarely have problems as I can convert units to SI quickly in my mind. Sometimes, I use conversion tables, now, available also on the net. One of them which are often used is pressure or stress unit; psi, lb-ft/inch^2. Also, fractions, decimals after commas are causing problems in tolerance things. Which is easier to work? 100 centimeter plus minus 1 centimeter or 3' 3" 1/2" plus minus 2/5"? (uff!:()
 

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