Published online by Cambridge University Press: 24 October 2008
In an alternating current motor (of simplest type) the internal E.M.F. e, the terminal tension e, the useful electrical power transformed p and the rotor phase angle φ are connected by the known formula
in which
where r is the resistance and l the self-inductance of the armature and ω the angular velocity of the rotor.
† Alternating Currents, Cambridge, 1906, Vol. 2, p. 143. It may be noted that Russell's formula holds in form when armature reaction is taken into account, but that then the position of the rotor is not accurately given by φ.