Question

Name the practical unit of power in engineering.

Answer 1

Hint: Power has different units in each discipline. In old times the power of the steam engine is quantified as the power of draft horses. Then, this unit has been used extensively to represent the power of mechanical motors.

Complete step by step answer:
Power is the rate at which work is done.
\[Power=\dfrac{Work}{time}\]
In engineering, the unit of power is collectively known as horsepower. It approximately equals 735.5 watts.

Additional information:
For a better understanding of engines, we need to learn the meaning of power and their various measurements. There are several types of horsepower which are used in different types of engineering. They are;
1. Indicated horsepower- The power generated in the cylinder and received by the piston is known as indicated horsepower. It helps to understand the factors affecting engine efficiency. It is the measure of total horsepower required for the developing process.
2. Belt horsepower- This horsepower is the actual usable power transferred to the engine crankshaft. It won’t be constant. It will change with engine speed.
3. Friction horsepower- Friction horsepower is the loss of indicated horsepower since the engine parts are rubbing together. Engine design and their usage are the main concern of this power.
4. Rated horsepower- It is the amount of power that the manufacturer declares about the engine. Generally, they will report about 80% of belt horsepower. It will make tears and problems to the engine if we load more than 80% of belt power. So, it is advised to use a more powerful engine to do heavy work.
5. Drawbar horsepower- It is the power developed at the drawbar. This horsepower is available for the pulling effort.

Note: It was a comparison of steam engines work with the output of dozens of horse’s works. So, for mechanical engines horsepower is the unit for power. Even though watts can also be used. One horsepower is similar to the 735.5 watts.