Question

A 40 kW engine has a mechanical efficiency of 80%. If the frictional power is assumed to be constant with load, what is the approximate value of the mechanical efficiency at 50% of the rated load?​

Answer 1

Answer:

75

Explanation:

40/80 used the formula find the ans

Answer 2

Answer:

66.6%

Explanation:

Given : A 40 kW engine has a mechanical efficiency of 80%. If the frictional power is assumed to be constant with load

To find: what is the approximate value of the mechanical efficiency at 50% of the rated load

Solution:

Find I P

=0 . 8 = B P / I P

get F P

using formula

F P = I P - B P

Find I P at  5 0 % load where

B P = 2 0 K W

and F P = 1 0 K W

Again,

2 0 / 3 0 * 1 0 0 = 6 6 . 6 %

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