This document discusses methods for measuring power in three-phase electrical circuits. It describes the three wattmeter method, where a wattmeter is placed in each phase to measure the power individually, and the readings are summed to obtain the total power. The current coils of the three wattmeters are connected to the respective phases, while the pressure coils are all connected to the neutral point. Each wattmeter will display the power of that individual phase as the product of phase current and line voltage. Adding the three readings gives the total power of the three-phase circuit.