POLY PHASE A C CIRCUITS CHAPTER 7 CONTENTS

POLY PHASE A. C. CIRCUITS CHAPTER 7

CONTENTS 1. Generation of Poly phase Voltages, Phase Sequence 2. Star or Wave (Y) connection - Values of Phase currents, Voltages in star and delta connection

Polyphase System • Phase means branch, circuit or winding while poly means many. • So such applications need a supply having many a. c voltages present in it simultaneously. • Such a system is called polyphase system.

Generation of Single phase voltage system

Generation of Three phase voltage system

Three Phase Alternator

Generation of Three phase voltage system

Generation of Three phase voltage system

Phase Sequence The sequence in which the voltages in three phases reach their maximum positive values is called Phase Sequence. Generally the phase sequence is R-Y-B.

Line Voltage & Line Current The potential difference between any two lines of supply is called LINE VOLTAGE and current passing through any line is called LINE CURRENT.

Line Voltage & Line Current In Star connection

Line Voltage & Line Current In Delta connection

Phase Voltage & Phase Current The potential difference between any line and neutral of supply is called PHASE VOLTAGE and current passing through any phase is called PHASE CURRENT.

Phase Voltage & Phase Current

Phase Voltage & Phase Current

END