Dynamometer

Dynamometer

A dynamometer is a device used for measuring the torque and brake power required to operate a driven machine.
Dynamometers can be broadly classified into two types. They are:

 <!--[endif]-->Power Absorption Dynamometers: Power Absorption dynamometers measure and absorb the power output of the engine to which they are coupled. The power absorbed is usually dissipated as heat by some means.
Examples of power absorption dynamometers are Prony brake dynamometer, Rope brake dynamometer, Eddy current dynamometer, Hydraulic dynamometer, etc.

Power Transmission Dynamometers: In power transmission dynamometers the power is transmitted to the load coupled to the engine after it is indicated on some scale. These are also called torque meters.

Some of the different types of dynamometers are discussed below in brief.

Prony Brake Dynamometer:

Pony Brake is one of the simplest dynamometers for measuring power output (brake power). It is to attempt to stop the engine using a brake on the flywheel and measure the weight which an arm attached to the brake will support, as it tries to rotate with the flywheel.

he Prony brake shown in the above consists of a wooden block, frame, rope, brake shoes and flywheel. It works on the principle of converting power into heat by dry friction. Spring-loaded bolts are provided to increase the friction by tightening the wooden block.
The whole of the power absorbed is converted into heat and hence this type of dynamometer must the cooled.
The brake power is given by the formula

Brake Power (bp) = 2π NT

Where T = Weight applied (W) × distance (l)