A $$230V,$$ $$50Hz,$$ $$4$$ pole, single phase induction motor is rotating in the clockwise (forward) direction at a speed of $$1425$$ $$rpm.$$ If the rotor resistance at standstill is $$7.8\,\,\Omega ,$$ then the effective rotor resistance in the backward branch of the equivalent circuit will be

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of $$5\% $$

If an auto-transformer is used for reduced voltage starting to provide $$1.5$$ per unit starting torque, the auto-transformer ratio $$\left( \% \right)$$ should be

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of $$5\% $$

If a starting torque of $$0.5$$ per unit is required then the per unit starting current should be

A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of $$5\% $$

If a star-delta starter is used to start this induction motor, the per unit staring torque will be