Introduction Classified by running gear: (1)Crawler tractor (2)Wheeled tractor (3)Hand tractor (4)Ship type tractor Classified by the watt level: Greater than 100 horsepower-Large sized tractor; Between 20 and 100 horsepower-Medium sized tractor; Less than 20 horsepower-Small tractors. 械电子工程学酸 Automobile and Tractor Northwest A&F University Automobile and Tractor Northwest A&F University Introduction Classified by running gear: (1) Crawler tractor (2) Wheeled tractor (3) Hand tractor (4) Ship type tractor Classified by the watt level: Greater than 100 horsepower — Large sized tractor; Between 20 and 100 horsepower — Medium sized tractor; Less than 20 horsepower — Small tractors