## Three Wattmeter and Two Wattmeter Method

Three Wattmeter and Two Wattmeter Method: In this method, the three wattmeter are connected in the three lines as shown in Fig. 9.45, i.e. the current coils of the three wattmeter are introduced in the three lines, and one terminal of each potential coil is connected to one terminal of the corresponding current coil, the […]

## Power in Three Phase Circuits

Power in Three Phase Circuits: Measurement of power by a wattmeter in a single phase circuit can be extended to measure Power in Three Phase Circuits. From earlier Section, it is clear that we require three wattmeters, one in each phase to measure the power consumed in a three-phase system. Obviously, the total power is […]

## Power Measurement in Single Phase Circuit by Wattmeter

Power Measurement in Single Phase Circuit by Wattmeter: Wattmeters are generally used to measure power in the circuits. A wattmeter principally consists of two coils, one coil is called the current coil, and the other the pressure or voltage coil. A diagrammatic representation of a wattmeter connected to measure power in a single phase circuit […]

## Unbalanced Three Phase Circuit Analysis

Unbalanced Three Phase Circuit Analysis: Types of Unbalanced Loads – An unbalance exists in a circuit when the impedances in one or more phases differ from the impedances of the other phases. In such a case, line or phase currents are different and are displaced from one another by unequal angles. So far, we have […]

## Three Phase Balanced Circuit

Three Phase Balanced Circuit: The analysis of Three Phase Balanced Circuit is presented in this section. It is no way different from the analysis of AC systems in general. The relation between voltages, currents and power in delta-connected and star-connected systems has already been discussed in earlier section. Balanced Three-Phase System-Delta Load: Figure 9.31(a) shows […]

## 3 Phase Delta Connection

3 Phase Delta Connection: Delta Connected System – Figure 9.26 shows a balanced three-phase, three-wire, delta-connected system. This arrangement is referred to as mesh connection because it forms a closed circuit. It is also known as 3 Phase Delta Connection because the three branches in the circuit can also be arranged in the shape of […]

## 3 Phase Star Connection

Voltage, Current and Power in 3 Phase Star Connection: 3 Phase Star Connection – Figure 9.21 shows a balanced three-phase, Y-connected system. The voltage induced in each winding is called the phase voltage (Vph). Likewise VRN, VYN and VBN represent the rms values of the induced voltages in each phase. The voltage available between any pair of […]

## Star Delta Transformation Formula

Star Delta Transformation Formula: While dealing with currents and voltages in loads, it is often necessary to convert a Star Delta Transformation Formula, and vice-versa. It has already been seen that delta (Δ) connection of resistances can be replaced by an equivalent star (Y) connection and vice-versa. Similar methods can be applied in the case […]

## Inter Connection of Three Phase Source and Loads

Inter Connection of Three Phase Source and Loads: Inter Connection of Three Phase Source and Loads consists of for Parts, Namely Inter Connection of Three Phase Source Wye or Star-Connection Delta or Mesh-connection Interconnection of Loads (a) Inter Connection of Three Phase Source: In a three-phase alternator, there are three independent phase windings or coils. […]

## Generation of Three Phase Voltage

Generation of Three Phase Voltage: Three Phase Voltage can be generated in a stationary armature with a rotating field structure, or in a rotating armature with a stationary field as shown in Fig. 9.2 (a and b). Single phase voltages and currents are generated by single phase generators as shown in Fig. 9.2(a). The armature […]