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 […]

Polyphase System

Polyphase System: In an ac system it is possible to connect two or more number of individual circuits to a common polyphase source. Though it is possible to have any number of sources in a polyphase system, the increase in the available power is not significant beyond the three-phase system. The power generated by the […]

Locus Diagram of Parallel RLC Circuit

Locus Diagram of Parallel RLC Circuit: (a) Variable XL – Locus plots are drawn for parallel branches containing RLC elements in a similar way as for series circuits. Here we have more than one current locus. Consider the Locus Diagram of Parallel RLC Circuit shown in Fig. 8.25(a). The quantities that may be varied are […]

Locus Diagram of RL Series Circuit

Locus Diagram of RL Series Circuit: To discuss the basis of representing a Locus Diagram of RL Series Circuit by means of a circle diagram consider the circuit shown in Fig. 8.19(a). The analytical procedure is greatly simplified by assuming that inductance elements have no resistance and that capacitors have no leakage current. The circuit […]