Farm Power and Machinery:
· Manual power – 0.1 HP; Animal power – 1.0 HP.
· The average force (or) draft animal can exert is nearly 1/10th of its body weight.
· If the wind velocity is more than 32 km/hr. wind mills can be used for lifting water.
· The unit power available for crop production in India is 1.54 hP/ha.
· “Heat engine” is an equipment which generates thermal energy and transforms it into mechanical energy.
· “External combustion engine” Eg: Steam engine.
· Internal combustion engine. Eg: Diesel & Petrol engine.
· IC engines classified as otto cycle, diesel cycle, Semi diesel cycle based on the type of working cycle.
· Tractors are mostly equipped with high speed engines running at about “1500RPM”.
· A pin called “Gudgeon pin (or) wrist pin” is provided for connecting the piston and the connecting rod. The end of the connecting rod which fits over the crankpin is called “Big end of the connecting rod”.
· A fly wheel is provided at the end of the crank shaft for smoothening the uneven torque produced by the engine.
· When the cycle is completed in two revolutions it is called four stroke, in one revolution – two stroke cycle engine.
· The movement of piston from BDC to TDC (or) TDC to BDC is called “Stroke”.
1. Suction stroke: Piston – moves downward; Inlet value – Opened. Exhaust value- Closed.
2. Compression stroke: Piston – moves upward; Inlet value – closed, exhaust – closed.
3. Power stroke: Piston – moves down; Inlet and Outlet – Closed.
4. Exhaust stroke: Piston – moves up; Inlet – closed; outlet – open.
· In two stroke engine three holes are provided known as Inlet port, transfer port and exhaust port. This piston is usually of the type is known as “Deflector piston”.
· “Scavenging” – The process of removal of burnt (or) exhaust gases from the engine cylinder.
· Thermal efficiency of diesel engine 32-38%. Petrol – 25-32%.
· Compression ratio of diesel engine 14:1 to 22:1; Petrol – 5:1 to 8:1.
· Compression pressure of diesel engine 35-45kg/cm2, Petrol 6-10kg/cm2.
· Compression temperature of diesel engine – 5000C; Petrol – 2600C.
· The most common type of valve is called “Poppet valve”.
· The sequence in which the power stroke in these cylinder of an engine occurs is called “firing orders” for four cylinder, four stroke engine the most commonly used firing order is 1-3-4-2, 1-2-4-3.
· The top of the piston is known as “Crown”. Sealing part is known as “Head”. The lower portion (guiding part) is called “Skirt” skirt diameter > Head diameter.
· Compression rings are usually plain, single piece oil rings are grooved.
· “Crank shaft” is the back bone of the engine.
· The space that supports the crankshaft in the cylinder block is called. “Main journal” where as the part to which connecting rod is attached is known as “Crank journal”.
· The crankpin along with two crank arms form “throw”.
· The portion which joins big end pin and main journal is called “web”.
· Cam shaft gear is bigger in size than that of the crankshaft gear and it has twice as many teeth as that of the crankshaft gear.
· The lower portion of the crank case is commonly called “Oil pan”. Two types of crank
case are
1. Split block type
2. Mono block type
· Cylinder is made up by high grade cast iron (fly wheel, crankcase also).
· Piston pin, connecting rod, crankshaft, cam shaft, forged steel.
· Gaskets – Cork (or) Copper is asbestos.
· Bore – It is the diameter of the engine cylinder.
· For tractor engines the stroke bore ratio is 1:25.
· Swept volume – piston displacement volume.
· Clearance volume – It is the space which holds the charge at TDC.
Total cylinder volume Swept vol. + Clearance Vol.
· Compression ratio =___________________ =________________
Clearance volume Clearance volume
· 1 metric HP = 75 kg.m/sec.
· Indicated horse power (1 HP). It is the power generated by all cylinders and receive by the piston. It is measured by a device called “Indicator”.
PLAn x PLAn
IHP =___ X __(4 – Stroke);______X x (2 – Stroke).
4500 2 4500
Where x = number of cylinders
· Break horse power (BHP) : It is the horse power delivered by the engine at the end of the pull loads crankshaft.
· Drawbar horse power (DBHP): It is the power which is used to pull loads.
· Frictional horse power (FHP) : It is the power required to run the engine at a given speed without producing any useful work.
FHP = IHP – BHP.
BHP
· Mechanical efficiency μ = _______X 100
IHP
· Power is measured by “Dynamometer”. DBHP is measured by “Hydraulic dynamometer”.
· Fuel supply system of diesel engine.
1. Gravity feed system: Diesel tank is placed above the level of fuel injection pump.
2. Forced feed system: Fuel is fed to the injection pump by a “lift pump (or) transfer pump”.
· Primary filters removes water and coarse particles of dirt form the fuel. Secondary filters removes “fine sediments”.
· Air cleaner is two types : 1. Dry type 2. Oil bath type
· Pre cleaner functions on the centrifugal principle.
· “Fuel lift pump” is a single acting (or) double acting plunger type pump. It is driven by a
camshaft of the engine.
· Fuel injection pump” should pump equal quantity of fuel to all cylinders.
· It creates pressure varying from 120-300 kg/cm2.
· In fuel injection pump “Delivery valve” prevents the reverse flow of fuel.
“Governer” maintain constant speed of the engine under different load conditions. It protect the engine and the attached equipment against high speeds when the load is reduced (or) removed.
· There are two systems of governers in IC engine
1. Hit and Miss system – Power stroke of the engine are regulated.
2. Throttle system – Suction stroke will be regulated.
· Distributor is made of bakellite (or) similar non conducting material.
· “Spark plug” is used for igniting highly compressed change in the combustion chamber.
· Electrolyte – 35% H2SO4 + 65% distilled water with a specific gravity of 1.28 in fully charged condition 1.15 (or) less when fully discharged condition. The specific gravity is measured by “Hydrometer”.
· Capacity of the battery is measured in “Ampere hour”.
· Mineral lubricant – Grease, SAE 40.
Fluid lubricant – oils, semi fluid lubricant – Grease, solid – Graphite, mica.
· High temperature lower the “Volumetric efficiency of the engine”.
· Too much removal of heat lower “thermal efficiency of the engine”.
· In “forced circulation method” centrifugal pump to circulate the water through out the water jocket.
· Radiators of two types 1. Tubular type 2. Cellular (Honey comb) type.
· Thermostat valves are of two types. 1. Bellow type 2. Bimetallic type
· Clutch: It is a device used to connect and disconnect the tractor engine from the transmission gears. It transmits power by means of friction between driving members and driven members.
· Clutches are 3 types
1. Friction clutch – used in 4 wheel tractors.
2. Dog clutch – In power tillers.
3. Fluid coupling clutch – 4 wheel tractor.
· Complete path from engine to wheel – power train.
2ΠNT
HP =_______
4500
T = torque in kg.m.
· Gears are usually made of alloy steel. SAE 90 oil is generally recommended for gear box.
· Gears are of two types
1. Selective sliding type
2. Constant mesh type
· Each “half shaft” terminates in a small gear which meshes with a large gear called “Bull gear”.
· The device for final speed reduction suitable for tractor rear wheel is known as “final drive mechanism”.
· Depreciation – loss of value of machine
D = (C-S) / LH
(C+S) i
Interest =_____ X_____
2 H
· Crawler tractor (track type (or) chain type) – Power tiller – walking type.
· “Row crop tractor” have more ground clearance.
· Central region farm machinery training and testing institute – Budni (MP).
Northern region – Hissar, Southern – Garladinne.
· At 200-250 engine working hours drain oil from oil sump.
· At every 480 – 500 working hours interchange tyres.
· Tillage is a mechanical manipulation of soil to provide favorable conditions for growing crops.
· Tractor drawn tillage implements.
1. Trailed implement: attached by a pin joint. The main body is supported on the ground but its weight is not supported by the tractor. The implement is pulled and guided from “Single hitch point”.
2. Semi mounted implement: It has rear wheel to support part of its weight.
· Mounted implement: It is attached to the tractor as an integral part.
· The combined unit of share, mould board, land side and frog is called “Plough bottom”.
· The forward end of the cutting edge – Share point.
· The front edge of the share which makes horizontal weight cutting edge of the share.
· The outer edge of the cutting edge of the share – wing of the share.
· The vertical face of the share which slides along the furrow wall is called “Gunnel”.
· Joint between mould board and share – Cleavage edge of the share.
· Share mostly used by the farmers “Slip share”.
· “Mould board” is that part of plough which receives the furrow slice from the share.
· Stubble type mould board” is adopted for ploughing on old ground “Sod (or) Breaker” type is used in sticky soils.
· “Frog” is that part of the plough bottom to which share, mould board and landside are attached rigidly.
· “Jointer” is a small irregular piece of metal having a shape similar to an ordinary plough bottom. It looks like a miniature plough.
· “Coulter” is a device used to cut the furrow slice vertically.
· Vertical suction (vertical clearance) : It is the maximum clearance under the land side and the horizontal surface when the plough is resting on a horizontal surface. It helps to the plough to penetrate into the soil to a proper depth.
· Horizontal suction: It is the maximum clearance between landside and a horizontal plane toching point of a share. It helps the plough to cut the proper width of a furrow slice.
· Throat clearance: it is perpendicular distance between point of share and the lever portion of the beam of a plough.
· Centre of resistance: It is a point where all the horizontal and vertical forces meet. It lies at a distance equal to 3/4th size of the plough from share wing.
· Line of pull: It is the line passing through the centre of pull, point of hitch and the centre of resistance.
· ‘Two – way (or) Reversible plough’ is suitable for terraced land of hilly tracts.
· Disc angle: It is the angle at which the plane of cutting edge of the disc is inclined to the direction of travel. It is usually between 420 – 450.
· Tilt angle: It is the angle at which the plane of cutting edge of the disc is inclined to a vertical line. It is usually varies from 150-250.
· For 60 cm diameter disc – 8 cm concavity.
95 cm diameter disc – 16 cm concavity.
· Scrapper: It is the device to remove soil that tend to stick to the working surface of a disc.
It prevents the discs from “Clogging”.
Plough bottom consists of Share, M.B, landside, frog Only circular concave steel disc
action of plough bottom Sliding type Rolling type
penetration of plough Due to suction Due to weight
· Depending upon the arrangement of disc. Disc harrows are divided into three classes
1. Single action: Consists of two gans of discs.
2. Double action: 4 gan of disc.
3. Offset : It is used in near tress in orchard. The line of pull is not in the middle.
· Gang: Each set of discs which are mounted on a common shaft is called gang.
· To prevent the lateral movement of the disc on the shaft is called “Spacer (or) Spool”. It is a device for keeping the discs at equal spacing on the gang bolt. It is generally made of cast iron.
· “Spike tooth harrow” – comes under “drag type”.
· Unbroken strip of soil left in between two gang of harrow distributed by “Middle type breaker”.
· In a sickle, forged end of the blade fitted into the handle is called “Tang”.
· Ledger plate: It is a hard end metal inserted in a guard (finger) over which knife sections move to give to a scissor like cutting action.
· Wearing plate: It is a hardened steel plate attached to the finger bar to form a bearing surface at the back of the knife.
· “Pitman” transmits reciprocating motion to a knife head.
· Alignment of a mover – cutter bar is set at about 880 to the direction at motion i.e. inward lead of 20.
· In krapsack sprayer the tank is filled 3/4th full.
· In hand compression sprayer the tank is filled 2/3 of its capacity.
Bits:-
· Device used to engage and disengage the tractor engine from the rest of the transmission is clutch.
· A gear reduction unit is the power train between the differential and drive wheel is called final drive (Increasing torque).
· Vertical disc plough is used for shallow ploughing.
· The procedure of testing the seed drill for correct seed rate is called calibration of seed drill.
· In dusters the hopper should be filled with dust about of its capacity 1/2 to 2/3.
· The opening and closing of the inlet and exhaust valves are controlled by the cam shaft.
· Gauge wheel helps to maintain uniformity in respect of depth of ploughing in different soil conditions.
· APAU drill – cup and cone mechanism.
· A mower knife is said to be in proper registration when the knife section stops in the centre of its guard on every stroke.
· The blade angle of the APAU puddler is 100.
· Concavity is the depth measured at the centre of the disc by placing its concave side on a flat surface.
· “Vertical disc plough” is also called as “Harrow plough”.
· The disc plough is less in draft than M.B.
· In splash lubrication system a dipper is provided at the lower end of the connecting rod”.
· Gradual application of the load of the vehicle on the engine when the vehicle starts from the rest is achieved by Clutch.
· The rear bottom of the land side is known as “Heel of land side”.
· The side pressure on the mould board is transmitted to the furrow wall by the “Land side”.
· Spacing between the row to row and plant to plant is same in “Check row method”.
· The parts of the seed drill which receive seed in longitudinal grooves and pass on to the seed tubes “Fluted roller”.
· The principle that “hot water being lighter rises up and the cold water being heavier goes down is used in “Thermosiphon” type of cooling system
· With hand sprayer, spray pressure can reach about 1-7 kg/cm2.
· To obtain complete inversion of soil the mould board used is sod (or) beaker type.
· In APAU puddler the axle is made of “Galvanised iron” (G.I) pipe.
· The detachable portion of an engine which covers the cylinder and includes combustion chamber, spark plug and values is known as “Cylinder head”.
