Answer to Question 1
The advantages that three phase motors have over single phase motors are:
They are easily reversible. The direction of rotation can be changed by interchanging any two supply voltage lines.
There is less running torque pulsation because at least one phase is always producing an induced rotational effect on the rotor.
They have higher starting torque because each winding is out of phase with the other windings and produces rotational torque.
They have higher efficiency.
Answer to Question 2
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