# Polyphase Circuits

## 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 …