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For a single cylinder reciprocating engine speed is 500 rpm, stroke is 150 mm, mass. of reciprocating parts is 21 kg; mass of revolving parts is 15 kg at crank radius. If twothirds of reciprocating masses and all the revolving masses are balanced, the mass at a radius of 150 mm will be (a) 7.5 kg (b) 10.5 kg (c) 12.5 kg (d) 14.5 kg |
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Answer» Correct option is (d) 14.5 kg N = 500 rpm ω = \(\cfrac{2\pi\times 500}{60}\) = 52.3598 rad/s r = \(\cfrac{150}2\) mm = 75 mm = 0.075 meter mreci = 21 kg mrot = 15 kg b = 150 mm = 0.150 meter B = ? Mass to be balanced = 2/3 Rotating+ Reciprocating = \(\left({15+\cfrac23\times21}\right)\) = 15 + 14 = 29 kg Total mass to be balanced m = 29 kg mrω2 = B·b·ω2 29 × 0.075 = B × 0.150 B = \(\cfrac{29\times0.075}{0.150}\) Kg B = 14.5 kg |
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