Does HP matter?

[nomad]

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.)

 

[EE_Bota]

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.

 

[nomad]

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.

 

[EE_Bota]

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.

 

[nomad]

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.

 

[mjncad]

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.

 

[SPYDERLK]

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

 

[RaydaKub]

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.

 

[LD1]

Yea, or go to the lumber yard and ask for a 2.5m 5x10........(8' 2x4):laughing:

 

[nomad]

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.

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!)