Just one wattmeter is needed, as shown in Figure 10. The machine link with the voltage and present terminals associated with wattmeter is easy. The voltage terminals associated with wattmeter are connected in parallel over the load, in addition to present is passed away through the present terminals that come in show with all the load.
Single-Phase Three-Wire Connection
In this technique, shown in Figure 11, the voltages are manufactured from 1 transformer that is center-tapped, and all sorts of voltages have been in period. This technique is typical in united states residential applications, where one 240 V and two 120 V materials can be found and could have various lots on each leg.
To gauge the power that is total other amounts, link two wattmeters as shown in Figure 11 below.
Figure 11. Solitary stage three wire wattmeter technique
Three-phase Three-Wire Connection (Two Wattmeter Method)
Where three cables can be found, two wattmeters have to measure total energy. Link the wattmeters as shown in Figure 12. The voltage terminals associated with the wattmeters are connected phase to stage.
Figure 12. Three-phase, three-wire, 2 wattmeter technique
Three-phase Connection that is three-Wire Wattmeter Technique)
Although just two wattmeters have to determine total energy in a three-wire system as shown previous, it really is often convenient to use three wattmeters.