CHAPTER 8 INTRODUCTION TO THREE PHASE CIRCUIT DMT
- Slides: 36
CHAPTER 8: INTRODUCTION TO THREE PHASE CIRCUIT DMT 122 CIRCUIT THEORY 2 SEMESTER 2 2018/2019 1
SINGLE PHASE SYSTEM Two wire type Three wire type 2
SINGLE PHASE SYSTEM § A generator connected through a pair of wire to a load – Single Phase Two Wire. § Vp is the magnitude of the source voltage, and is the phase. § Use at normal household 3
2 -PHASE SYSTEM § A generator consists of two coils placed perpendicular to each other § The voltage generated by one lags the other by 90. 4
3 -PHASE SYSTEM § A generator consists of three coils placed 120 apart. § Consist of 3 sources § The voltage generated are equal in magnitude but, out of phase by 120. 5
IMPORTANCE OF 3 - PHASE SYSTEM § All electric power is generated and distributed in three phase. § Uniform power transmission (instantaneous power is constant) and less vibration of three phase machines. § Three phase system is more economical than the single phase. 6
BALANCED 3 -PHASE VOLTAGES § Produced with a 3 -phase ac generator. § Generator consist of rotating magnet (rotor) & stationary winding (stator) § 3 separate windings (coils) with terminal a-a’, b-b’ and cc’ placed 120° apart around the stator § When rotor rotates, magnetic field induced a voltage with same magnitude but of phase 120°. Balanced 3 -phase voltages : equal in magnitude & out of phase by 120° 7
BALANCED 3 VOLTAGES § Balanced three phase voltages: § same magnitude (VM ) § 120 phase shift +ve sequence -ve sequence 8
BALANCED 3 CURRENTS § Balanced three phase currents: § same magnitude (IM ) § 120 phase shift 9
POSITIVE PHASE SEQUENCE § POSITIVE SEQUENCE (abc)10
NEGATIVE PHASE SEQUENCE § NEGATIVE SEQUENCE (acb) 11
DETERMINE THE SEQUENCE USING PHASOR DIAGRAM 12
EXAMPLE 1 § EXAMPLE 2 13
3 -PHASE QUANTITIES QUANTITY SYMBOL Phase current I Phase voltage V Line current IL Line voltage VL 14
PHASE VOLTAGES and PHASE CURRENTS § Phase voltage (V ) : measured between the neutral and any line voltage. § Phase current (I ) : the current in each phase of the source or load. 15
PROPERTIES OF PHASE VOLTAGE § 16
PROPERTIES OF PHASE CURRENT § All phase currents have the same magnitude, § Out of phase with each other by 120 17
LINE VOLTAGES and LINE CURRENTS § Line voltage (VL) : measured between any two of the three lines. § Line current (IL) : the current in each line of the source or load. 18
PROPERTIES OF LINE VOLTAGE § 19
PROPERTIES OF LINE CURRENT § All line currents have the same magnitude, § Out of phase with each other by 120 20
BALANCED VOLTAGE AND LOAD § Balanced Phase Voltage: All phase voltages are equal in magnitude and are out of phase with each other by 120. § Balanced Load: The phase impedances magnitude and in phase. are equal in 21
SOURCE-LOAD CONNECTION SOURCE LOAD Wye (Y) Delta (∆) CONNECTION 22
SOURCE LOAD Delta (∆) Wye (Y) CONNECTION 23
BALANCED Y-Y CONNECTION § 24
BALANCED Y-Y CONNECTION § Total impedance per phase, ZY 25
BALANCED Y-Y CONNECTION § 26
BALANCED Y-Y CONNECTION § 27
BALANCED Y-Y CONNECTION § 28
EXAMPLE 3 § Calculate : (assume negative sequence) i. The line voltages ii. The line currents 29
EXAMPLE 4 Calculate : (assume positive sequence) i. The line voltages ii. The line currents 30
BALANCED ∆ - ∆ CONNECTION § 31
BALANCED ∆ - ∆ CONNECTION § 32
BALANCED ∆ - ∆ CONNECTION § 33
BALANCED ∆ - ∆ CONNECTION § 34
EXAMPLE 5 A balanced delta connected load having an impedance 20 -j 15 is connected to a delta connected, positive sequence generator having Vab = 330 0 V. Calculate : i. the phase currents ii. the line currents. 35
EXAMPLE 6 § 36
- Polyphase ac
- Introduction to semiconductor physics
- Dmt 234
- Dmt 234
- Dmt
- Physic
- The pythagorean theorem
- Dmt
- Dmt fabrication
- Layout dmt
- Dmt monitor
- Population decline
- A balanced delta connected load having an impedance 20-j15
- Motor equivalent circuit
- Normal phase vs reverse phase chromatography
- M tswett pronunciation
- Mobile phase and stationary phase
- Mobile phase vs stationary phase
- Normal phase vs reverse phase chromatography
- Line current and phase current
- Hplc detector types
- In a ∆-connected source feeding a y-connected load
- Broad phase vs narrow phase
- 3 phase short circuit
- Series vs parallel
- Types of circuit
- Circuit construction kit
- Capacitor series parallel
- What is a incomplete circuit
- Short circuit example
- Series and parallel circuits similarities
- Pulmonary circuit and systemic circuit
- Series parallel circuit current
- Three phase model of operant conditioning
- Power formula three phase
- Single phase uncontrolled half wave rectifier
- Three component system phase diagram