What does a phase rotation indicator primarily measure?

A phase rotation indicator is primarily used to assess the sequence of phases in three-phase systems. This is crucial in many applications, as the correct phase sequence ensures that motors and other equipment operate correctly and efficiently. If the phase sequence is incorrect, it can lead to malfunctioning or even damage to equipment. The measurement is typically made by applying the indicator to the three-phase supply and observing the rotation direction, which reveals the order of the phases.

Understanding phase rotation is essential for technicians, as many three-phase devices are designed to operate with specific phase sequences. If the sequence is changed—for example, reversing two of the phases—it can cause motors to run in the wrong direction, leading to operational failures or safety issues.

The other choices do not pertain to what a phase rotation indicator specifically measures. The total current flowing in the system relates to current measurement tools, voltage levels across phases are monitored with voltmeters, and frequency is measured with frequency analyzers. Each of these tools serves different functions and does not provide information about phase rotation, reinforcing the significance of using a phase rotation indicator for its intended purpose.