WHAT IS DYNAMOMETER | DYNAMOMETER |TYPES | MECHANICAL

"DYNAMOMETER:-

                           A dynamometers are also a brake but in addition It has a device to measure the frictional resistance , knowing the frictional resistance.

We may find the torque transmitted and hence the power of the engine.

Types of dynamometer : -

    Mainly there are the two types of

dynamometers used for measuring the

 power of an engine

1.) Absorption dynamometers.

2.) Transmission dynamometers.

1. Absorption dynamometers :-

                                                   Here In the absorption type dynamometer the entire energy produced by the engine and it is observed by the frictional resistance of the brake .it is transmitted into heat , during the process of measurement.

Classification of absorption type dynamometer :-

a) Prony brake dynamometer

b) Rope brake dynamometor.

a ) Prony brake dynamometer :- 

                                                 It is the simplest form of an absorption type dynamometer is a prony brake dynamometer. It consists of 2 wooden blocks placed around a pulley fixed to the shaft of an engine whose power is required to be measured. These blocks are clamped by means of 2 bolts and nuts, a helical spring is given between the nut and the upper block to adjust pressure on the pulley to control its speed. The upper block has a long lever attached to it and car a weight W at its outer end. A counter weight is placed at the other end of the lever which balances brake when unloaded. 



PRONY BRAKE DYNAMOMETER

When the brake is in the operation, the long end of the lever is loaded with suitable

weights and the nuts are fixed tightened until the engine shaft runs at a constant speed and the lever is in

horizontal position. In these conditions, the moment due to the weight must balance the moment of the frictional resistance between these blocks and the pulley.

Dynamometers measure the power of the engines.

Here we let., 

W = it is the Weight at the outer end of the lever in newtons,

L = it is the Horizontal distance of the weight W

from the centre of the pulley in metres,

F = it is the Frictional resistance between the blocks

and the pulley in newtons,

R = it is the Radius of the pulley in metres, and

N = it is the Speed of the shaft in r.p.m.

We know that the moment of the frictional re-

sistance or torque on the shaft,

 T = W.L = F.R N-m

Work done in one revolution

 = Torque × Angle turned in radians

 = T × π2 N-m

 ∴ Work done per minute

 = T N × π2 N-m



b) ROPE BRAKE DYNAMOMETER:-

It is another form of absorption dynamometer which is most commonly used for measuring the brake power of the engine. It consists of 1,2 or more ropes wound around the flywheel or

rim of a pulley fixed tightly to the shaft of an engine. 

ROPE BRAKE DYNAMOMETER

The upper end of the ropes is attached to a spring balance while the lower end of the ropes is kept in position by applying a dead weight .In order to prevent the slipping of the rope over the flywheel, wooden blocks are placed at intervals around the circumference of the flywheel.

In the operation of the brake, the engine is made to run at a constant speed. 



Here we Let 

W = Dead load in newtons,

S = Spring balance reading in newtons,

D = Diameter of the wheel in metres,

d = diameter of rope in metres, and

N = it is the Speed of the engine shaft in r.p.m.

∴ Net load on the brake

 = (W – S) N

We know that distance moved in one revolution

 = π + ( D+d)m



2. TRANSMISSION DYNAMOMETER:-

In this dynamometer, after the indication of power on some type of any scale. It is transmitted by the load couples by the engine. It is also called torque meter.