JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II FARM MACHINERY AND EQUIPMENTS-I Previous Question Paper (July/August - 2021 - R13)

Given: Swath width (w) = 1.9 m, Speed (s) = 2.5 kmph, Field efficiency (η) = 70% or 0.70.

Theoretical field capacity (TFC) = (w × s) / 10 = (1.9 × 2.5) / 10 = 0.475 ha/h.

Effective field capacity (EFC) = TFC × η = 0.475 × 0.70 = 0.3325 ha/h.

Mould board ploughs are classified based on the shape of the mould board and the type of share used.

Types of Mould boards:

• General Purpose: Has a medium length with a gradual twist. It is used for average soil conditions and provides good pulverization.
• Stubble: Short and abrupt with a sharp curvature. Designed for turning heavy stubble and sod quickly, resulting in less pulverization.
• Sod (Breaker): Long with a very gradual twist. It is designed to turn over thick, tough sod without breaking it significantly, ensuring the vegetation is completely buried.
• High Speed: Designed with a flatter curvature to allow soil to move across the surface at higher tractor speeds without excessive scattering.

Types of Shares:

• Share point: A separate piece attached to the front of the share to improve penetration in hard soils.
• Slip nose share: Features a detachable point that can be replaced when worn, making it economical.
• Chisel point share: Similar to a slip nose but with a longer, more aggressive point for deep penetration in compact soils.
• Solid share: The share and point are forged as a single unit, commonly used in general-purpose ploughs.

Line diagrams would typically depict the curvature profiles for the mould boards (varying from abrupt to gradual) and the cutting edge geometry for the different share types.