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Unformatted text preview: axis of A and D. If the wheels B and D have 25 teeth and 40 teeth respectively, find the
number of teeth on C and the speed and sense of rotation of C.
[Ans. 30 ; 600 r.p.m. clockwise] Fig. 13.35
7. l Fig. 13.36 Fig. 13.36, shows an epicyclic gear train with the following details :
A has 40 teeth external (fixed gear) ; B has 80 teeth internal ; C - D is a compound wheel having 20 and
50 teeth (external) respectively, E-F is a compound wheel having 20 and 40 teeth (external) respectively, and G has 90 teeth (external).
The arm runs at 100 r.p.m. in clockwise direction. Determine the speeds for gears C, E, and B .
[Ans. 300 r.p.m. clockwise ; 400 r.p.m. anticlockwise ; 150 r.p.m. clockwise] 8. An epicyclic gear train, as shown in Fig. 13.37, has a sun wheel S of 30 teeth and two planet wheels
P-P of 50 teeth. The planet wheels mesh with the internal teeth of a fixed annulus A . The driving shaft
carrying the sunwheel, transmits 4 kW at 300 r.p.m. The driven shaft is connected to an arm which
carries the planet wheels. Determine the speed of the driven shaft and the torque transmitted, if the
overall efficiency is 95%.
[Ans. 56.3 r.p.m. ; 644.5 N-m] Fig. 13.37
9. Fig. 13.38 An epicyclic reduction gear, as shown in Fig. 13.38, has a shaft A fixed to arm B . The arm B has a pin
fixed to its outer end and two gears C and E which are rigidly fixed, revolve on this pin. Gear C
meshes with annular wheel D and gear E with pinion F. G is the driver pulley and D is kept stationary.
The number of teeth are : D = 80 ; C = 10 ; E = 24 and F = 18.
If the pulley G runs at 200 r.p.m. ; find the speed of shaft A .
[Ans. 17.14 r.p.m. in the same direction as that of G] 476
10. l Theory of Machines A reverted epicyclic gear train for a hoist block is shown in
Fig. 13.39. The arm E is keyed to the same shaft as the load
drum and the wheel A is keyed to a second shaft which carries a chain wheel, the chain being operated by hand. The
two shafts have common axis but can rotate independently....
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- Fall '08