Induction Motor
Speed of Stator magnetic field = Ns
Speed of rotor = Nr
Slip, S = (Ns-Nr) / Nr
As the stator magnetic field rotates at Ns and the rotor rotates at Nr in the same direction the relative speed of magnetic field with respect to conductor is Ns-Nr
In case of Induction motor the stator and rotor frequency are unequal so if s<1 rotor frequency is generally smaller as compare to stator frequency.
•Step 1:- 3-phase supply on stator rotating magnetic rotates at Ns w.r.t stator (ground)
•Step 2:- rotor rotates at Nr
•Step 3:- frequency of V,I induced on rotor = sf
•Step 4:- Speed of rotor magnetic field w.r.t rotor
rotor = 120*s*f/p = sNs
•Step 5:- Speed of rotor magnetic field w.r.t stator or ground
sNs+Nr = Ns-Nr+Nr = Ns
