Red Seal Industrial Electrician Practice Exam

Phase sequence in three-phase systems specifically refers to the order in which the three voltage waveforms reach their peak values. This sequence is critical because it determines the direction of rotation in motors and affects the performance and stability of the electrical system.

In a three-phase system, each phase voltage can be thought of as a sinusoidal wave that oscillates over time. The sequence (commonly referred to as ABC or ACB) identifies which phase reaches its maximum voltage first, second, and last. This is significant in ensuring that motors are connected properly, as an incorrect phase sequence can result in reverse rotation, potentially damaging the motor or affecting the operation of connected equipment.

The other options do not accurately define phase sequence. The method of synchronizing phases relates more to aligning voltage levels between different systems rather than the order of voltages. The configuration of circuit breakers describes how they are arranged, which is not related to phase sequence. Lastly, the number of phases in a system is a separate concept; a three-phase system inherently consists of three phases regardless of the specific phase sequence.