What Does Horsepower Really Mean

   / What Does Horsepower Really Mean #1  

Williy

Elite Member
Joined
Apr 26, 2020
Messages
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Location
Texas
Tractor
Yanmar YT 235C Yannar YRC 60 rotary cutter, Yanmar RT72 rotary tiller B75 Backhoe & bucket & thumb, LS land grader

I get this information from Yanmar because I have a Yanmar Tractor
On their website you can get information like:

Resources

I only have 118 hours on my tractor so far no problems and enjoy using my Yanmar also have the 10 year drive train warranty​

Yanmar tractors might cost more than some other tractors but you get more.

willy
 
   / What Does Horsepower Really Mean #2  
Their explanation of what 1 horsepower is makes me wonder if

A horse wouldn’t really notice that it’s lifting 33lbs. It would only realize it has to run 1000’ in 60 seconds. The efficiency between a trot, run and a gallop would be a bigger factor than the 33 lb bucket it’s pulling out of the well.

A horse pulling 330 lbs out of a hundred foot well in a minute seems more relatable.

…but know a 1/10th horsepower motor can pull the 330lbs up too if you have 10 minutes to spare.
 
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   / What Does Horsepower Really Mean #3  
It's really quite simple.

Disclaimer: I'm a retired nuclear reactor operator and dealt with thermodynamics and power conversion for 38 years.

You need to have a delineation between the theoretical word and the real word. What I mean by that is, in the link I provided below, there is reference to moving a load over a certain distance over a certain time. This negates any friction or other resistance. In the energy conversion process, you end up with the same energy that you started with before you even started to move the load. It's just spread out with generally 30% of the energy moving the object and the rest to the environment. Google "Conservation of energy".

Ok, maybe it's not so simple. So simply more horsepower, the faster you can move the load.

(don't get turned off that link comes from an auto manufacturer)

What is Horsepower and Why Does it Matter?
 
   / What Does Horsepower Really Mean #4  
I am a big proponent of looking at a tractors drawbar HP.

When I started running a really heavy square baler, I was worried about being able to afford a tractor with enough HP to run it. What I really needed was the drawbar HP to pull it. When I did my homework, I found the older Case-IH Magnums had excellent drawbar HP. Theres a lot of older affordable Magnums out there, so it wasn’t such a big deal.

It’s a real eye opener to see how some tractors clobber other competitive tractors in drawbar HP, even though the engines may have the same or similar HP.
More people should pay attention to this.

“Drawbar horsepower is a measurement of a tractor’s ability to pull an implement determined by pulling a weighted load that is fitted with a strain gauge to determine pull. Maximum ground speed is also measured. In many ways, drawbar horsepower is a true measure of the power the tractor can use to pull the implement. It is not only a function of engine power and drivetrain loss, but also the machine’s ability to transfer the load to the tire”
 
   / What Does Horsepower Really Mean #5  
Another similar (maybe better) question is "What is work"...horsepower can be described as the rate at which "work" is done...!
 
   / What Does Horsepower Really Mean #6  
Their explanation of what 1 horsepower is makes me wonder if

A horse would really notice that it’s lifting 33lbs. It would only realize it has to run 1000’ in 60 seconds. The efficiency between a trot, run and a gallop would be a bigger factor than the 33 lb bucket it’s pulling out of the well.

A horse pulling 330 lbs out of a hundred foot well in a minute seems more relatable.

…but know a 1/10th horsepower motor can pull the 330lbs up too if you have 10 minutes to spare.

An actual horse is significantly stronger than 1hp for some length of time. I assume that the rating was reduced to a level that the horse could sustain all day.
 
   / What Does Horsepower Really Mean #7  
HP as a measurement is somewhat meaningless. If you take 400 horses and put them in a rope pull contest, with anything that says it has 400 HP, it will lose. Some one should do this in a you tubes. My 1220 tractor has a rating of 14 HP. 14 horses I wound need th
It's really quite simple.

Disclaimer: I'm a retired nuclear reactor operator and dealt with thermodynamics and power conversion for 38 years.

You need to have a delineation between the theoretical word and the real word. What I mean by that is, in the link I provided below, there is reference to moving a load over a certain distance over a certain time. This negates any friction or other resistance. In the energy conversion process, you end up with the same energy that you started with before you even started to move the load. It's just spread out with generally 30% of the energy moving the object and the rest to the environment. Google "Conservation of energy".

Ok, maybe it's not so simple. So simply more horsepower, the faster you can move the load.

(don't get turned off that link comes from an auto manufacturer)

What is Horsepower and Why Does it Matter?

And the tasks. And this number is meaningless, cause my garden CUB Cadet tractor has a rating of 25 HP. These can't be the same. I don't lift entire cars out of a ditch with the lawn tractor that has so much power. with HP
 
   / What Does Horsepower Really Mean #8  
Brake Hp, PTO Hp, drawbar Hp, horsey Hp, all the same. It's the transmission package that changes.
 
   / What Does Horsepower Really Mean #9  
HP as a measurement is somewhat meaningless. If you take 400 horses and put them in a rope pull contest, with anything that says it has 400 HP, it will lose. Some one should do this in a you tubes. My 1220 tractor has a rating of 14 HP. 14 horses I wound need th


And the tasks. And this number is meaningless, cause my garden CUB Cadet tractor has a rating of 25 HP. These can't be the same. I don't lift entire cars out of a ditch with the lawn tractor that has so much power. with HP
They ARE the same but less meaningful unless you put in rpm. Your cub cadet is probably rated 25hp@ 4000rpm or so meaning much less torque available to the wheels at low speed than 25hp @2000rpm. And it also depends on how you are further geared from the engine to the wheels - transmission, differential, and wheel size.

My kioti can’t really pull itself up the hill in high, but in low I can pull anything I want until the wheels spin…..same thing. Same tractor, same 35hp rating, one transmission ratio is useless for anything other than flat land travel (but it does that at a relatively high speed)
 
   / What Does Horsepower Really Mean #10  
I understand hp is derived from torque, and remember Horsepower = Torque x RPM / 5,252
If you see a hp/torque graph for an engine, from 1 to 10,000 hp the two curves cross at 5,252. At that rpm hp=torque.
You have to be older to remember the great Smokey Yunick (we met him years ago at his shop in Daytona. He said if you look at two motor graphs, I'll take the one with a flatter curve. Motorcycles for example may rev to the moon but hp is "peaky".
I pulled our farrier's Dodge Ram 3500 diesel out of a ditch last winter in the snow with my 140hp F-150 six cyl.4x4 pickup 4 speed farm truck. It's geared low and has a granny 4x4 low 1st gear. Just above idle...probably 4mph.
If you connected my 14hp 1cyl. Economy tractor to my two Cub 24hp 2cyl mowers it would drag them wherever you wanted.
Watch this...probably 100:1 ratio of horsepower difference and 100+ years apart!
 
 
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