engineering recuitment UPCL AE (E&M) 2021 Mock Test Design of Machine Elements Power Screws Efficiency of Screws
The maximum efficiency of screw jack is (when ϕ - angle of friction):
1
\(\eta = \frac{{1 - sin\phi }}{{1 + sin\phi }} \)
2
\(\eta = \frac{{1 + sin\phi }}{{1 - sin\phi }} \)
3
\(\eta = \frac{{1 - tan\phi }}{{1 + tan\phi }} \)
4
\(\eta = \frac{{1 + tan\phi }}{{1 - tan\phi }} \)