How many degrees apart is each phase winding in a three-phase alternator?

How many degrees apart is each phase winding in a three-phase alternator?

• A. 120 degrees
• B. 90 degrees
• C. 60 degrees
• D. 180 degrees

Answer: (A)

Three-phase operation relies on three sinusoidal voltages that are spaced 120 electrical degrees apart. To achieve this, the phase windings are positioned around the stator so that each winding’s induced EMF reaches its peak sequentially by 120 electrical degrees. The electrical angle is tied to the mechanical angle by the number of pole pairs, so this physical spacing translates into equal phase shifts among the three voltages. That equal 120-degree separation is what gives a rotating magnetic field and smooth, balanced power output. If the windings were spaced differently, the phase relationships wouldn’t be correct for a true three-phase system, producing less smooth or unbalanced power.

Three-phase operation relies on three sinusoidal voltages that are spaced 120 electrical degrees apart. To achieve this, the phase windings are positioned around the stator so that each winding’s induced EMF reaches its peak sequentially by 120 electrical degrees. The electrical angle is tied to the mechanical angle by the number of pole pairs, so this physical spacing translates into equal phase shifts among the three voltages. That equal 120-degree separation is what gives a rotating magnetic field and smooth, balanced power output. If the windings were spaced differently, the phase relationships wouldn’t be correct for a true three-phase system, producing less smooth or unbalanced power.