# Farm Machinery Questions and Answers – Farm Tractor – Clutch and Fluid Coupling – 2

This set of Basic Farm Machinery Questions and Answers focuses on “Farm Tractor – Clutch and Fluid Coupling – 2”.

1. Multi plate clutch, when coolant is required, is also known as ______
a) Dry Clutch
b) Wet Clutch
c) Field Clutch
d) Dog Clutch

Explanation: During relative motion due to engagement power loss occurs causing heat generation so coolant is required so multi plate clutch is also known as wet clutch.

2. A multi disc clutch has 4 steel discs and 3 bronze disc. The outside and inside diameter of contact surfaces are 250 mm and 180 mm respectively. The coefficient of friction is 0.3 and axial force is 400 N assuming uniform wear. The power in kw that clutch can transmit at 1000 rpm is ______
a) 4.05 KW
b) 16.20 KW
c) 8.10 KW
d) 32.40 KW

Explanation: n=n1+n2-1 = 6
T = 154.8/2 = 77.4 Nm
P = $$\frac{2πNT}{60} = \frac{2*3.14*1000*77.4}{60}$$ = 8.10 KW

3. Determine the maximum pressure in a plate when axial force is 4 KN. The radius of contact surface is 50 mm outside radius is 100 mm.
a) 0.255 N/mm
b) 0.319 N/mm
c) 0.248 N/mm
d) 0.303 N/mm

Explanation: Pmax = $$\frac{W}{2πr[r0-ri]} = \frac{4000}{2*3.14*0.05[0.05]}$$ = 0.255 N/mm

4. A multiple disc clutch, steel on bronze is to transmit 6 HP at 750 rpm. The inner radius of contact is 4cm and outer radius of contact is 7 cm. Coefficient of friction is 0.1 and the average allowable pressure is 3.5 kgf/cm2. Find the actual axial force required.
a) 2335.09 N
b) 2590.90 N
c) 1999.76 N
d) 2143.65 N

Explanation:Explanation: P = $$\frac{2πNT}{60}$$
T = $$\frac{6*746*60}{6.28*750}$$=57 Nm
T = ημWReff
ηW = 2*5181.81
3.5 * 9.8*10^4 = $$\frac{W}{π[49-16]*10^{-4}}$$
W = 3554.16
N = 2.91
Actual axial force
T = ημWactReff
Wact = $$\frac{57*2}{4*0.1*0.1}$$ = 2590.90 N

5. Which displacement can be achieved by toothed type clutch?
a) Positive displacement
b) Negative displacement
c) Neutral displacement
d) Divisional displacement

Explanation: Positive displacement can be achieved by toothed type gear because when it is engaged there will be no sliding occurring between the contact surface.
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6. What is the uniform pressure theory for new clutch plated?
a) T = η+μ+ W+Reff
b) T = η – μ – W – Reff
c) T = ημWReff
d) T = 1 – (ημWReff)

Explanation: W = P * π (r02-ri2)
T = $$∫_{ri}^{r0}$$dT = $$∫_{ri}^{r0}$$μP2πr2dr
T = $$\frac{2}{3}$$ μW$$[\frac{r0^3-ri^3}{r0^2-ri^2}]$$
T = ημWReff

7. In single plate clutch there is no need of coolant, hence it is also known as ______
a) Wet clutch
b) Damp clutch
c) Dog clutch
d) Dry clutch

Explanation: In short plate clutch, there is no need of coolant so it is also known as dry clutch. Coolant is not used because it reduces the coefficient of friction and as a result torque transmission is decreased.

8. Determine the minimum and average pressure in a plate when axial force is 4 KN. The radius of contact surface is 50 mm outside radius is 100 mm.
a) 0.127 N/mm; 0.17 N/mm
b) 0.186 N/mm; 0.10 N/mm
c) 0.183 N/mm; 0.18 N/mm
d) 0.120 N/mm; 0.72 N/mm

Explanation:
Explanation: Pmin = $$\frac{W}{2πr[r0-ri]} = \frac{4000}{2*3.14*0.1[0.05]}$$ = 0.127 N/mm
Average pressure, P = $$\frac{W}{\pi[r0^2-ri^2]} = \frac{4000}{π[0.1^2-0.05^2]}$$ = 0.17 N/mm

Sanfoundry Global Education & Learning Series – Farm Machinery.