An epicyclic gear train is shown in the figure below. The

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An epicyclic gear train is shown in the figure below. The number of teeth on the gears A, B and D are 20, 30 and 20 respectively. Gear C has 80 teeth on the inner surface and 100 teeth on the outer surface. If the carrier arm AB is fixed and the sun gear A rotates at 300 rpm in the clockwise direction, then the rpm of D in the clockwise direction is

1. 240
2. –240
3. 375
4. –375

Correct Option: C

T_A = 20,
T_B = 30,
T_D = 20,
T_C = 80 (Inner)
T_D = 100 (outer)
Arm is fixed, no epicyclic nature.
Taking clockwise direction as positive.
N_A = +300

(A, B)N_B =	-300 × 20	= -200
	30

(C, C)N_C = -200 ×	30	= -75
	80

(C, D)N_D = +75 ×	100	= +375
	20