Phase sequence is defined as which of the following?

Phase sequence is defined as which of the following?

• A. The sequence of switching in the control circuit
• B. The color codes of the wires
• C. The pattern the conductors must connect in the same way throughout the system for proper rotation
• D. The phase angle between line voltages

Answer: (C)

Phase sequence determines the direction of rotation in a three-phase system by the order in which the three phase voltages reach their peaks. To keep motors and equipment turning in the intended direction, the conductors feeding all machines must be connected in the same order throughout the system. If the sequence is not consistent, or if the order is altered somewhere, the rotating magnetic field can reverse and the motor may spin the wrong way. Why the other ideas don’t fit: the switching order in a control circuit describes how devices operate over time, not the inherent order of the three voltages themselves; wire color codes identify phases but don’t enforce the sequence; and the phase angle between line voltages (about 120 degrees) describes the geometry of the voltages, not the sequence that dictates rotation.

Phase sequence determines the direction of rotation in a three-phase system by the order in which the three phase voltages reach their peaks. To keep motors and equipment turning in the intended direction, the conductors feeding all machines must be connected in the same order throughout the system. If the sequence is not consistent, or if the order is altered somewhere, the rotating magnetic field can reverse and the motor may spin the wrong way.

Why the other ideas don’t fit: the switching order in a control circuit describes how devices operate over time, not the inherent order of the three voltages themselves; wire color codes identify phases but don’t enforce the sequence; and the phase angle between line voltages (about 120 degrees) describes the geometry of the voltages, not the sequence that dictates rotation.