What is the name of the tester used to verify phase sequence?

• A. Wattmeter
• B. Phase angle meter
• C. Phase sequence tester
• D. Phase rotation meter

Answer: (D)

Verifying phase sequence requires a tester that reveals the order in which the three-phase voltages reach their peaks. A phase rotation meter, also called a phase sequence tester, is designed for this purpose. It connects to the three lines and uses indicators (lights or a small rotating display) to show whether the sequence is, for example, L1-L2-L3 or the opposite. This lets you confirm and correct motor wiring so the rotation direction is as intended. A wattmeter measures power, and a phase angle meter measures the angle between two signals, neither of which directly tells you the phase order. The device shown in this context is the phase rotation meter.