The different sources of farm power for various agricultural operations are classified as- 1. Human power 2. Animal power 3. Mechanical power (Tractors, Power tillers, and Oil engines) 4. Electrical power 5. Renewable energy (Biogas, Solar energy, and Wind energy) Human power is the main source for operating small implements and tools at the farm. Stationary work like chaff cutting, lifting, water,. Animals are still widely used as a major power source in many countries. Land preparation, weed management, crop threshing, and transport are executed using animal power. Electrical power is used mostly in the form of electrical motors on the farms. The motor is a very useful machine for farmers. It is clean, quest and smooth running. Its maintenance and operation need less attention and care. The operating cost remains almost. Broadly speaking, mechanical power includes stationary oil engines, tractors, power tillers, and self-propelled combines. The internal combustion engine is a good device for converting liquid fuel into useful work (mechanical work). These engines are two types- 1.