How many degrees are the poles set apart in a three-phase motor?

• A. 90 degrees
• B. 120 degrees
• C. 180 degrees
• D. 360 degrees

Answer: (B)

In a three-phase motor, the poles are set apart by 120 degrees. This configuration is essential for the effective functioning of the motor, as it allows for a continuous rotation of the magnetic field, which is necessary to produce torque and enable the motor to operate smoothly.

In a three-phase system, the three phases are evenly spaced around a circle of 360 degrees. Since there are three phases in a typical three-phase motor, the angle between each phase is obtained by dividing the total degrees in a circle by the number of phases. This calculation shows that each phase is separated by 120 degrees (360 degrees / 3 phases = 120 degrees).

This arrangement ensures that at any given time, one of the phases is always at its peak voltage, driving the rotor continuously and efficiently. This systematic spacing is what differentiates three-phase motors from single-phase motors, where the phases are not present or not equally distributed, leading to less efficient operation.