B7500 Horsepower rating??? The decal on the motor says its 23.5
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DmansPadge
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Maybe the 23.5 number is gross HP... so things like the alternator, fan, etc. aren't deducted for HP loss.
herringchoker
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I noticed the same thing on my B7800 - sticker on engine says output is 26.5 kw, which works out to over 35 HP (if my metric conversion is correct), while Kubota advertises 30 engine hp and 22 at the PTO. I was thinking the gross / net thing too, but over 5 HP to run the fan and dynamo seems a bit high to me. Maybe Kubota's advertised HP's are a bit conservative? 
One thing I do know - the little tractor is a real powerhouse!
One thing I do know - the little tractor is a real powerhouse! 
RoyJackson
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There are three common methods to rate horse power (not including Gross, Net, PTO and drawbar).
In the US, we use SAE methods, in Europe, mostly DIN (German) and Japan has it's ratings which I think is JIS. They're all a bit different, so the same engine tested under the same conditions using the different methods would result in different ratings. I don't recall how much different though, but if I recall correctly, SAE ratings are higher then DIN. BTW, there's also a metric rating, but I don't think that's used often (relying on kW ratings instead).
So, your engines may have been tested using a method other then what you're used to seeing in the US.
Also, no manufacturer tests all their engines (well, some do....I think Deere tests all their large equipment engines). The HP ratings we see with our machines may be an average of several production engines (your engines may have been one of the tested engines), or calculated (based upon all specs being at nominal...this isn't reliable, IMHO).
The advertised HP may be the average or calculated rating. Production engines may produce a little more, or less, then the advertised rating.
In the US, we use SAE methods, in Europe, mostly DIN (German) and Japan has it's ratings which I think is JIS. They're all a bit different, so the same engine tested under the same conditions using the different methods would result in different ratings. I don't recall how much different though, but if I recall correctly, SAE ratings are higher then DIN. BTW, there's also a metric rating, but I don't think that's used often (relying on kW ratings instead).
So, your engines may have been tested using a method other then what you're used to seeing in the US.
Also, no manufacturer tests all their engines (well, some do....I think Deere tests all their large equipment engines). The HP ratings we see with our machines may be an average of several production engines (your engines may have been one of the tested engines), or calculated (based upon all specs being at nominal...this isn't reliable, IMHO).
The advertised HP may be the average or calculated rating. Production engines may produce a little more, or less, then the advertised rating.
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I do not have any wisdom about the different rating on the engines but I believe that 1hp in the US is the same HP in Germany, Japan or in China for that fact. If I remember correctly my former physics teacher said. The power output that equals to one horse power is to lift a 75KG weight to a height of 1 meter in one second. That is the definition I have heard. So. Saying that 1HP in Germany is different from that in Indiana is to say that the earth rotated faster at one place or another, because that is what it would take to change power required to accomplish the above mentioned task. Even if my numbers are off there is a mathematical definition of 1HP that should be the same any place.
crbr
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That is true.easygo said:
Hence, that mathematical definition is expressed in different manners, according to the standard in which it was calculated.
RoyJ is telling you correct.
Or the sticker may be in a miscombobulation status.
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RoyJackson
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easygo said:
Should be...yes...but it's not. Metrology (the science of measurement) is like anything else. Politics, economics and nationalism sometimes intrude on what should be an impartial, disciplined methodology.
After all, we in the U.S. should be using the metric system, shouldn't we?
RoyJackson
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easygo said:
Well, there is in a way...most tractors (other motorized equipment too, I suppose) have kW ratings too.
We're just not used to looking at kW ratings yet.
Roy,
I thought the Kw rating is just a converted measurement of the engine output that was derived from the HP rating with some math. How do they establish the Kw output vs the Hp output and why is it a more consistent way to describe the "strength" of an engine? I know that even some car manufacturers give Kw rating as well but I just never payed any attention to that.
I thought the Kw rating is just a converted measurement of the engine output that was derived from the HP rating with some math. How do they establish the Kw output vs the Hp output and why is it a more consistent way to describe the "strength" of an engine? I know that even some car manufacturers give Kw rating as well but I just never payed any attention to that.