Total flux produced by the rotor currents does not link with the stator winding. The part of rotor flux that links the rotor conductors but not with the stator winding is called leakages flux and hence develops leakage inductance (L2). The leakage flux and hence the inductance is very small, if the rotor conductors are placed at the outermost periphery of the rotor as shown in Figure 12.11. Depending upon the rotor current frequency, rotor reactance will be developed.
Fig. 12.11 Leakage flux
X2 = 2 × π × fr × L2 = 2 × π × S × f × L2 = S ×(2 × π × f × L2)
When the rotor is standstill, that is, at the start, when slip, S = 1
The value of rotor reactance = X2s= 2 × π × f × L2
Therefore, under normal running, rotor reactance, X2 = S × X2s
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