Dynamometers are devices used to measure torque and power. There are two types: absorption dynamometers and transmission dynamometers. Absorption dynamometers absorb the engine's power through frictional resistance, which is transformed into heat. Transmission dynamometers transmit the engine's energy for work. Common absorption dynamometers include the Prony brake and rope brake, which measure torque by balancing frictional resistance with a weight. Transmission dynamometers include the epicyclic train dynamometer, belt dynamometer, and torsion dynamometer, which transmit power through gear trains, belts, or shaft twisting.

1. DYNAMOMETERS
(Theory of Machine – I)
Prepared By
Prof. D. S. Dabhade
Department of Mechanical Engineering
MGM’S Jawaharlal Nehru Engineering College ,Aurangabad

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Dynamometer –
It is a device to measure frictional resistance.
- Torque transmitted , Power of Engine
Types of Dynamometers
1. Absorption Dynamometers
i . Prony Brake Dynamometer
ii . Rope Brake Dynamometer
2. Transmission Dynamometers
i. Epicyclic train dynamometer
ii. Belt transmission dynamometer
iii. Torsion dynamometer
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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Absorption Dynamometers
During Process of Measurement…
 Total Power / Energy Produced is absorbed by
frictional resistance
 Transformed in to Heat
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

4. 1. Prony Brake Dynamometer
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 Load the lever end with suitable weight W
 Nuts are tightened until –
Engine shaft runs at constant speed and
Lever is in horizontal position.
 Under these condition must satisfy …
Moment due to Weight W = Moment due to Frictional Resistance
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

6. 2. Rope Brake Dynamometer
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 Engine runs at a constant speed
 Under these condition must satisfy …
Frictional torque due to rope = Torque transmitted by engine
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

8. TranTransmission Dynamometers
- During Process of Measurement…
 Energy is utilized for work done
 Energy/ Power developed by engine is transmitted through
dynamometer to other machine.
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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

9. 1. Epicyclic train dynamometer
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 Friction of pin on which pinion rotates is neglected
 Tangential effort P exerted by spur on pinion and tangential reaction of
annular gear on pinion are equal
 Total upward force on lever = 2P
Tends to rotate the lever about fulcrum
Balanced by a dead wt W at end of lever
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

11. 2. Belt transmission dynamometer
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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

13. 3. Torsion Dynamometer
When power transmitted…
 Driving end of shaft twist through small angle relative to driven
 Amount of twist depends upon factors…
i. Torque acting on shaft (T)
ii. Length of Shaft (L)
iii. Diameter of Shaft (D)
iv. Modulus of Rigidity (C)
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Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

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We Know that
Prof. D.S.DABHADE ,
Department of Mechanical Engineering ,
MGM’S J. N. E. C, Aurangabad

15. Thank You…
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