Fleming's rules

Fleming's rules

Fleming's rules are aids for remembering the relationships between the directions of the current, field, and motion in electric motors and generators.


In the left-hand rule (for motors), the forefinger represents field, the second finger current, and the thumb, motion; when the digits are extended at right-angles to each other, the appropriate directions are indicated. The right-hand rule applies the same principles for generators.


The rules were devised by the English electrical engineer John Fleming (1849–1945).