Calculation of Rotor’s Current and MMF in a Squirrel Cage Induction Machine

This paper presents a method for calculation of bar’s currents and its magneto motive force (MMF) in a squirrel cage induction machine. For this propose, at first multiple coupled circuit modeling of cage induction motor is introduced. Then with the aim of dynamic equations, an analytic expression for bar’s currents will be derived. This equation can introduce the instantaneous values of currents in all bars. At next section, this equation is simplified for the steady state operation of machine. At the end, the equation of MMF produced by rotors will be derived based on analytic bar’s equation and winding function theory.