This set of Farm Machinery Multiple Choice Questions on “Farm Tractor – Clutch and Fluid Coupling – 1”.
1. A single plate clutch with both sides effective, has an outer diameter of 30 cm and inner diameter of 20 cm. the maximum intensity of pressure at any point in the contact surface is not exceed 1 kg/cm2. If the co-efficient of friction is 0.3, determine the horse power transmitted by a clutch speed of 2000 rev/min.
a) 65.73 HP
b) 98.75 HP
c) 45.29 HP
d) 51.17 HP
Answer: a
Explanation: T= n*μ*W*rm
W = 2πC(r0-ri)
pmax.ri = C
Combining the above equations
T = nμ2π pmax. ri(r0-ri) rm
T = 2*0.3*2π*1*10(15-10) *12.5
T = 2355 kg cm = 23.55 kg m
P = (frac{2πNT}{4500}=frac{2π*23.55*2200}{4500}) = 65.73 HP
2. A multiple disc clutch is composed of 5 steels and 4 bronze discs. The clutch is required to transmit 16 Nm of torque. If the inner diameter is restricted to 50 mm, determine the necessary outer diameter of the discs. (Co-efficient of friction=0.1)
a) 63 mm
b) 35 mm
c) 70 mm
d) 14 mm
Answer: c
Explanation: T = nμW (frac{(r0^3-ri^3 )}{r0^2-ri^2}*frac{2}{3} )
16 = 8*0.1*350*π(r02-ri2)(left[frac{r0^3-ri^3}{r0^2-ri^2}right] )
16 = 8*0.1*350*π*[r03-(0.25)3]
r0 = 35 mm
d0 = 2*35 = 70 mm
3. A multidisc clutch, n=8, d0=15cm, di=11 cm. Determine the total load on springs, power = 8hp, N=1000 rpm, μ=0.08.
a) 163.133 N
b) 200.147 N
c) 157.142 N
d) 186.150 N
Answer: c
Explanation: rm = (frac{ri+r0}{2}=frac{0.075+0.055}{2}) = 0.065 m
P = (frac{2πNT}{4500} )
T = (frac{P*4500}{2πN}=frac{8*4500}{2π*1000})=5.72 Nm
T = neμWrm
W = (frac{(T)}{ne*μ*rm}=frac{5.72}{7*0.08*0.065} )
= 157.142 N
4. An impeller with radial vanes constituting the driving member and runner with radial vanes constituting the driven member is found in ______
a) Fluid coupling
b) Dog clutch
c) Friction clutch
d) Cone clutch
Answer: a
Explanation: Fluid coupling consists of a driving member and a driven member. An impeller with radial vanes constitute the driving member and runner with radial vanes constitute the driven member. The entire unit is housed in a suitable casing.
5. Which type of clutch has got number of thin metal plates, arranged alternately to work as driving and driven members?
a) Dog clutch
b) Fluid coupling
c) Multiple plate clutch
d) Single plate clutch
Answer: c
Explanation: Multiple plate clutch may be multiple disc clutch. It has got number of thin metal plates, arranged alternately to work as driving and driven members. One set is attached to flywheel and the other set is attached to the clutch shaft.
6. How much oil is filled in the coupler of the fluid coupling?
a) 4/5
b) 2/3
c) (frac{1}{2} )
d) (frac{3}{4} )
Answer: d
Explanation: A coupler is mounted on the engine crankshaft and is 3/4th filled with suitable oil. A spring-loaded sealing ring is provided to make the driven shaft oil tight.
7. 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
Answer: d
Explanation: T = (frac{2}{3}) nμW (left[frac{r0^3-ri^3}{r0^2-ri^2}right] )
= (frac{2}{3})nμpπ(r02-ri2) (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
8. What is the pressure in the new uniform pressure theory?
a) Pressure = w+π(r02-ri2)
b) Pressure = (frac{w}{π{r02-ri2}} )
c) Pressure = w*π(r02-ri2)
d) Pressure = w-π(r02-ri2)
Answer: b
Explanation: The uniform theory is applicable only when the friction lining is new. The pressure in the new uniform pressure theory is (frac{w}{π{r02-ri2}}. )