induction motorrotorstator
Here is an equivalent circuit of a rotor on an Induction motor:
Can someone explain How do we arrive at this circuit?
The rotor seems to be only a disc(made of a metal) with conductors embedded near the circumference like here: http://www.ece.umn.edu/users/riaz/animations/imwound.html
Now, how can i further simplify the equivalent circuit of the three phase motor
Try this one: -
Taken from here
The slip at locked rotor is 1, so the rotor resistance and reactance are connected directly to neutral for the per phase model.
Diagram from Fizgarald Kingsley Umans "Electric Machinery" 4th ed
Best Answer
There's a pretty good website here. Here's the first picture of the equivalent circuit of the whole motor: -
The section in the OP's question is the secondary side of the picture i.e. the rotor. Resistor \$R_R\$ represents the real mechanical output power of the motor and \$jX_R\$ represents the impedance of the rotor winding.
The transformer is there because the rotor is coupled to the stator by transformer action. This diagram is only one-third of the full picture of a 3-phase induction motor.
The website goes through the relatively simple theory of converting the circuit to its more usable form: -
Here, the term "s" is used on the rotor output (represented by \$R_2\$ now) to properly relate output power to the slip of the rotor compared to synchronous machines that do not slip.