If load (or torque) angle of a 4-pole synchronous motor is 6° electrical, its value in mechanical degrees is

The correct answer is $\boxed{\text{B) 3}}$.

The load angle is the angle between the rotor and stator magnetic fields. In a 4-pole synchronous motor, the rotor and stator magnetic fields are aligned when the motor is at standstill. As the motor accelerates, the rotor magnetic field lags behind the stator magnetic field. The load angle is the angle between the two fields at any given time.

The load angle is measured in electrical degrees. One electrical degree is equal to one-sixtieth of a mechanical degree. Therefore, a load angle of 6 electrical degrees is equal to 3 mechanical degrees.

The following is a brief explanation of each option:

• Option A: 2 mechanical degrees. This is incorrect because 2 mechanical degrees is equal to 12 electrical degrees.
• Option B: 3 mechanical degrees. This is the correct answer because 3 mechanical degrees is equal to 6 electrical degrees.
• Option C: 4 mechanical degrees. This is incorrect because 4 mechanical degrees is equal to 8 electrical degrees.
• Option D: 6 mechanical degrees. This is incorrect because 6 mechanical degrees is equal to 12 electrical degrees.