Main Flux Path Calculations Using Magnetic Circuits

Having determined the MMF forcing function, it is now necessary to calculate the fluxes and MMF drops in the main magnetic circuit of an induction machine. This chapter serves as one of the two key elements in the design of an electrical machine, namely the determination of the magnetizing flux paths in the machine portions. The magnetizing flux, interacting with the induced rotor current, determines, in essence, the developed torque in an induction machine. The chapter then considers three key areas of the magnetic circuit: the air gap, the teeth, and the core. It further considers the calculation of the MMF drop in the air gap and rotor teeth over one tooth pitch. The total MMF drop around the magnetic circuits is obtained by summing up the individual MMF drop around the entire magnetic circuit comprised of two air gaps, two stator and rotor teeth, and the stator core and the rotor core.