Induction Motor as a transformer:
Â· As we know for a transformer two windings must be magnetically coupled.
Â· When primary winding is connected to an AC supply emf gets enduced into the secondary as per the principle of induction.
Â· Induction motor also operates on the principle of induction as when stator winding is connected to an AC supply then an AC voltage will be generated in the rotor winding hence we are calling it as an rotating transformer.
Â· Transformation Ration is given as:
K=E2/E1=N2/N1 at N=0 or S=1
E1=Stator emf per phase
E2=Rotor emf per phase
N2=Number of rotor turns
N1=number of stator turns
v Torque Equation of Induction motor:
Â· We can Produce torque in the induction motor with the help of below parameters;
i) The rotor power factor
ii) The rotor Current
iii) Part of rotating magnetic field which induces emf in the rotor winding.
Combinely we can write it as:-
T α Î¦T2rCosÎ¦2r
Î¦=Flux induced in induction motor
cosÎ¦2r=Rotor power factor