What principle does a phase sequence indicator rely on?

A phase sequence indicator is a tool designed specifically for identifying the phase sequence in a three-phase electrical system. The phase sequence refers to the order in which the phases reach their peak voltage, which is crucial for the correct operation of three-phase motors and other equipment. An incorrect phase sequence can lead to motors running in reverse or other operational issues, making it essential for technicians to ensure the correct sequence is established before connecting or troubleshooting equipment.

The operation of a phase sequence indicator involves measuring the voltage relationships among the three phases and determining the sequence in which they occur. This is why the principle that it relies on is the ability to determine the order of phases in a three-phase system.

In contrast, measuring total circuit resistance, assessing current, or calculating load do not pertain to the primary function of a phase sequence indicator. These functions are relevant to other types of electrical measurement tools but do not address the specific need for identifying the order of phases.