Tom QP 2 Final PDF

Q.11. Classify Cam and Followers Classifica on of Follower 1. According to the surface in contact (a) Knife edge follower. (b) Roller follower (c) Flat faced or mushroom follower. (d) Spherical faced follower 2. According to the mo on of the follower. (a)...

Q.11. Classify Cam and Followers Classifica on of Follower 1. According to the surface in contact (a) Knife edge follower. (b) Roller follower (c) Flat faced or mushroom follower. (d) Spherical faced follower 2. According to the mo on of the follower. (a) Reciproca ng or transla ng follower. (b) Oscilla ng or rota ng follower 3. According to the path of mo on of the follower (a) Radial follower (b) Off-set follower. Classifica on of Cams 1. Radial or disc cam 2. Cylindrical cam Q.12. Write short note on the following a) Explain the working of internal expanding shoe brake. b) Classify brakes Types of Brakes The brakes, according to the means used for transforming the energy by the braking elements, are classified as 1. Hydraulic brakes e.g. pumps or hydrodynamic brake and fluid agitator, 2. Electric brakes e.g. generators and eddy current brakes, 3. Mechanical brakes The mechanical brakes, according to the direc on of ac ng force, may be divided into the following two groups : (I) Radial brakes (II) Axial brakes c) State the advantages of double shoe brake over single shoe brake. d) State the advantages and disadvantages of belt drives. e) Classify belt drives f) Define base circle, prime circle, pitch point, pitch curve in cam drive Base circle. It is the smallest circle that can be drawn to the cam profile. Prime circle. It is the smallest circle that can be drawn from the centre of the cam and tangent to the pitch curve. For a knife edge and a flat face follower, the prime circle and the base circle are iden cal. For a roller follower, the prime circle is larger than the base circle by the radius of the roller. Pitch point. It is a point on the pitch curve having the maximum pressure angle. Pitch curve. It is the curve generated by the trace point as the follower moves rela ve to the cam. For a knife edge follower, the pitch curve and the cam profile are same whereas for a roller follower, they are separated by the radius of the roller. g) difference between Governor and Flywheel Q. 13. Answer the following a) Explain slip and creep in belt drive. b) Explain the construc on and working of differen al gear box c) What is ini al tension in belt drive? d) State the factors that affects power transmission in belt drive. e) State the func ons of Governor and Flywheel The func on of a governor is to regulate the mean speed of an engine, when there are varia ons in the load e.g. when the load on an engine increases, its speed decreases, therefore it becomes necessary to increase the supply of working fluid. On the other hand, when the load on the engine decreases, its speed increases and thus less working fluid is required. The governor automa cally controls the supply of working fluid to the engine with the varying load condi ons and keeps the mean speed within certain limits.