A question of kW

[Stef]

I looked at my B3030 engine and read the tag on it. It's written that the output is 26.5 kW. When you translate it to HP it gives (factor 1.34102209) 35.54hp. That's odd. When I look at Kubota's specs it says 22.4 kW engine gross horsepower (30hp). Kubota use the same translation factor as my calculator (written above).

The first thing that came to my mind is: Ho... 35.54hp is the gross horsepower, but I looked at Kubota's specs and 30hp is the gross hp.

So, what do you think guys?

Here's a pic showing the tag on my engine.

 

[Stef]

Volfandt, found the same contradiction on his BX23:

Kubota's specs: 16.4 kW (22hp)
The tag on his engine: 18.5 kW (24.81hp)

Here's the link

 

[RoyJackson]

Due to manufacturing tolerances, the same design engine can produce more or less then the advertised horsepower. The advertised horsepower can be (so I have read) the average of a sample of engines actually dynoed HP, or more commonly, a number calculated by the designer based upon every component being at nominal.

Another variable to consider is how the Japanese calculate horsepower (or Kw) based upon their JIS (Japanese Industrial Standards) specifications versus how US manufacturers calculate their HP ratings based upon SAE specs.

Also, tractors have three possible HP ratings: Gross Engine HP (most auxiliaries are removed); PTO horsepower (we're all familiar with that); and draw bar HP (more for larger tractor..a rating of what they can pull).

In the cases described in the posts in this thread, I suggest these "discrepancies" are due to manufacturing tolerances vs. advertised HP.

 

[johnday]

Stef; Rocket Scientist I'm not, But I believe there is 748 watts per each HP. When my calculator multiples 30 HP times 748, it comes up with 22,440 watts. Pretty close to 22.4 kW.

Where did you get that calculator? /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[RoyJackson]

1 horsepower = 745.699872 watts

 

[johnday]

Now Roy, you didn't specify if those are Japanese, US, or Euro, kW. /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif What am I to think!! /forums/images/graemlins/confused.gif /forums/images/graemlins/grin.gif

 

[RoyJackson]

BTW, 22.4kW divided by 0.7457 equals 30.04 HP.

I think you may have used the wrong conversion.

 

[Stef]

I thought about that... American, Japenese

But on Kubota.com, the specs for a B3030 is:

<font color="red"> Engine gross horsepower HP (kW): B3030 30.0 (22.4)</font>

If my conversion is wrong then theirs is too.

1 HP = 745.699871 watt = 0.745699871 kW
1 kW = 1.34102209 HP

Kubota uses on his website the exact conversion as I have here.

 

[Junkman]

Kubota is a company that can't even get the quarts of oil correct for the engine, so what makes anyone think that they can do complex equations that will yield the total horsepower of the engine? /forums/images/graemlins/confused.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/crazy.gif

 

[ccsial]

Just a guess but maybe the 26.5KW is the max. output while the 22.4KW is the continuous duty rating.