Electrical Machines
When R2 is rotor resistance, X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condition will be

  sR2 = X2.
  R2 = s2X2.
  R2 = s2X2.
  R2 = sX2.

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Electrical Machines
Due to magnetic saturation, the flux per pole in a DC machine without brush shift

 increases in both the generators and the motors with load.
 decreases in generators and increases in motor with load.
 increases in generators but decreases in motor with load.
  decreases in both generators and the motors with load.

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