# design of shafts....

**Question description**

A hoisting drum 0.5 m in diameter is keyed to a shaft which is supported in two

bearings and driven through a 12 : 1 reduction ratio by an electric motor. Determine the power of the

driving motor, if the maximum load of 8 kN is hoisted at a speed of 50 m/min and the efficiency of the

drive is 80%. Also determine the torque on the drum shaft and the speed of the motor in r.p.m.

Determine also the diameter of the shaft made of machinery steel, the working stresses of which are

115 MPa in tension and 50 MPa in shear. The drive gear whose diameter is 450 mm is mounted at the

end of the shaft such that it overhangs the nearest bearing by 150 mm. The combined shock and

fatigue factors for bending and torsion may be taken as 2 and 1.5 respectively.

## Tutor Answer

Brown University

1271 Tutors

California Institute of Technology

2131 Tutors

Carnegie Mellon University

982 Tutors

Columbia University

1256 Tutors

Dartmouth University

2113 Tutors

Emory University

2279 Tutors

Harvard University

599 Tutors

Massachusetts Institute of Technology

2319 Tutors

New York University

1645 Tutors

Notre Dam University

1911 Tutors

Oklahoma University

2122 Tutors

Pennsylvania State University

932 Tutors

Princeton University

1211 Tutors

Stanford University

983 Tutors

University of California

1282 Tutors

Oxford University

123 Tutors

Yale University

2325 Tutors