Phasemeter
Is an electrical measuring device designed to measure phase angles between two periodically changing electrical oscillations, for example, to measure the phase shift between current and voltage in an industrial frequency alternating current circuit, also in a three-phase power supply system.
Generally, used in electrical installations to determine the active power factor cos φ (hence its slang name, "cosine meter," often due to ignorance of electrical installation personnel of the correct name of the instrument). Phase meters are used in developing, adjusting, and operating electronic and electrical apparatus and devices [Academic].
A phase meter is a diagnostic tool used to detect electrical waves transmitted through a power source and measures the overall delivery of electricity. These devices run continuously, measuring voltage and the ensuing current supplied to any electrical circuit to provide an accurate reading of overall power consumption. On standard models, an aluminum dial is connected to a readout screen to display the amount of power used at any given time by monitoring the number of revolutions the disk makes per hour. The resulting numbers on a phase energy meter are displayed in kilowatt-hours (kWh) or megajoules (MJ) to determine the total usage for that structure. Properties equipped with a phase meter are billed at specific intervals for the total usage of kWh or MJ, depending on their geographical location. A history of the average usage is recorded by the electricity provider [About Mechanics].
A device for measuring the difference in phase of two alternating currents of electromotive forces [TheFreeDictionary].
Фазометр. Academic. Retrieved from: https://dic.academic.ru/dic.nsf/ruwiki/694613
Phase Meter. About Mechanics. Retrieved from: https://www.aboutmechanics.com/what-is-a-phase-meter.htm
Phase meter. TheFreeDictionary. Retrieved from: https://www.thefreedictionary.com/Phase+meter