Polyphase Wattmeter

This wattmeter consists of 2 or 3 single-phase wattmeters mounted in the same package. The watt sensing elements can be electronic transducers or analog dynamometers. A dual element wattmeter will measure power in a 3 phase 3-wire system regardless of power factor, voltage or current variations between phases. Most common analog dynamometer forms are 2, 2-1/2, or 3 element types. In 4-wire circuits with the 4th wire carrying current, the 2-1/2 or 3 element types is used. If there is voltage unbalance, only the 3 element is suitable.