Question

A safety clutch is mounted on the drive shaft of a mower cutter bar. The clutch disc is active on both sides and has inner and outer diameters of 6 and 14 cm respectively. The friction co-efficient of the material of the clutch has to start slipping at 10Nm torque, the pressure acting on the clutch plate (assuming uniform pressure conditions) will be _______

(a) 53.04 kPa

(b) 13.26 kPa

(c) 7.96 kPa

(d) 25.18 kPa

This question was addressed to me in an interview.

The question is from Farm Tractor in division Farm Tractor of Farm Machinery

Answer 1

Right choice is (d) 25.18 kPa

For explanation I would say: T = \(\frac{2}{3}\) nμW \(\left[\frac{r0^3-ri^3}{r0^2-ri^2}\right] \)

= \(\frac{2}{3}\)nμpπ(r0^2-ri^2) \(\left[\frac{r0^3-ri^3}{r0^2-ri^2}\right] \)

P = \(\frac{3T}{2nμπ(r0^3-ri^3)} = \frac{3*10}{2*2*0.3*π \{ 0.07^3-0.03^3 \}}\) = 25182.74 Nm^-2

P = 25.18 kPa