Subtopic: Functional requirements, principles of working, construction and operation of manual, animal, tractor and renewable energy operated equipment for tillage, sowing, planting, fertilizer application, inter-cultivation, spraying, mowing, chaff cutting, harvesting and threshing
Question Statement:
Which of the following conditions lead to increased grain damage (cracking) during mechanical threshing in a spike-tooth or rasp-bar cylinder?
Options:
(A) Excessively high peripheral drum speed
(B) Extremely low concave clearance
(C) Low grain moisture content below $12\%$
(D) Very high feed rate exceeding cylinder capacity
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
- Excessively high peripheral speed increases impact kinetic energy, causing grain cracking.
- Too small concave clearance causes excessive mechanical pinching and crushing.
- Low grain moisture (< 12%) makes the grain brittle and highly susceptible to mechanical shatter.
- Overfeeding typically leads to unthreshed heads and cylinder clogging (threshing loss), rather than increased grain cracking.