In a balanced three-phase electrical system, the phase EMFs differ in phase by how many degrees?

In a balanced three-phase electrical system, the phase EMFs differ in phase by how many degrees?

• A. 120 Degrees
• B. Square Root of 3
• C. 90 Degrees
• D. Zero Degrees

Answer: (A)

In a balanced three-phase system, the phase voltages are equal in magnitude and separated by 120 degrees in phase. This 120-degree spacing means each phase reaches its peak one-third of a cycle after the next, creating a rotating magnetic field and smooth, constant power delivery. In phasor form, the three phase voltages are 120 degrees apart, so the phase EMFs differ by 120 degrees. The other options don’t fit because 90 degrees would be a quadrature shift, zero degrees would put all phases in step, and sqrt(3) is a voltage magnitude ratio (line to phase), not an angular difference.

In a balanced three-phase system, the phase voltages are equal in magnitude and separated by 120 degrees in phase. This 120-degree spacing means each phase reaches its peak one-third of a cycle after the next, creating a rotating magnetic field and smooth, constant power delivery. In phasor form, the three phase voltages are 120 degrees apart, so the phase EMFs differ by 120 degrees. The other options don’t fit because 90 degrees would be a quadrature shift, zero degrees would put all phases in step, and sqrt(3) is a voltage magnitude ratio (line to phase), not an angular difference.