The rotor of a d.c. motor is fixed on the midspan of a 10 mm diameter, 300 mm long steel shaft rotating at 600 r.p.m. and supported on spherical bearings. The mass of the rotor is 10 kg.
- Determine the maximum dynamic stress on the shaft for a speed of 0.8 times the critical speed.
- What will happen when the shaft is rotated at 0.95 times the critical speed?
Assume for steel:
E = 2.2 x 105 N/mm2; Yield strength = 220 MPa
Ultimate strength = 20 MPa