A phase rotation indicator is an electrical device used to determine the correct phase sequence (rotation) in a three-phase electrical supply system. It is used primarily to ensure that a motor or other equipment will rotate correctly and will not be damaged before connecting it to a three-phase power system. If the phase rotation is misconnected, the motor may rotate backwards, which can cause equipment damage or accidents.
This indicator is usually lightweight and easy to use, and it accurately indicates the phase sequence—L1, L2, L3. It is an important tool for electricians, engineers, and technicians, especially in industrial or commercial installations. Some phase rotation indicators also have audio or visual signals, which help to indicate the correct or incorrect phase sequence. By determining the correct phase rotation, it ensures the safety of the equipment and reduces operational risks.