Horse Power

[Jeffro]

I understand horsepower i. e. 500 horses pulling.

What I don`t understand is Brake horsepower. Can someone please explain it in simple language please?

[snapdarlich]

http://en.wikipedia.org/wiki/Brake_horsepower#Brake_horsepower_.28bhp.29 Hope this helps

[JudgeJ]

To save you wading through the Wikipedia stuff, Jeffro, Brake Horsepower (bhp) is calculated by subjecting the machine being assessed (eg the petrol engine or electric motor or whatever) to a test on something called a dynamometer. This effectively measures the output of the engine by applying a brake to it to establish how much force is needed to stop it rotating. Hence the term brake horsepower.

Incidentally, although it was originally based on the power of the average horse, "Horsepower" is a precise measurement. It is the power needed to raise 550 pounds one foot in one second.

[Loosehead]

Further to the judge, in the early days of motoring "Horsepower" was determined using an equation based on the volume and number of cylinders. In the modern era of course, engine size bears very little relation to power output so the "brake" horsepower is used an accurate measure of actual power.