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An engine is mounted on four rubber pads such that the static deflection is 5mm. if the mass of the engine and coupling is 300kg at what speed motor run for 95% isolation?

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An engine is mounted on four rubber pads such that the static deflection is 5mm. if the mass of the engine and coupling is 300kg at what speed motor run for 95% isolation?

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written 5.0 years ago by |

Number of pads = 4

Static deflection = $\delta st$ = 5mm = 0.005m

M = 300 kg

$\eta_{iso} = 95%$

N = ?

$\xi \ = \ 0$

$\eta \ iso \ = \ 1 - T_r$

0.95 = 1 – $T_r$

$T_r$ = 0.05

$Tr = \frac{\sqrt{1 + (2 \xi r)^2}}{\sqrt{ (r^2 – 1)^2 + (2 \xi r)^2}}$

$0.05 = \frac{1}{r^2 – 1}$

$r^2 – 1 = 20$

$r^2 = 19$

r = 4.358

$w_n = \sqrt{ \frac{9}{\delta_{st}}} = \sqrt{\frac{9.81}{0.005}} = 44.29 $ rad/sec

$r = \frac{w}{w_n}$

$4.358 \times 44.29 = w$

w = 202.86 rad/sec

$w = \frac{2 \pi N}{60}$

N = 85857.86 rpm.

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