ELE 2103 Dept . of E & E, MIT Manipal Transformers ELE 2103 Dept . of E & E, MIT Manipal Transformers AC (Single Phase, Three Phase)

ELE 2103 Dept of E & E, MIT Manipal Single phase Transformer Introduction to Transformers Classifications Representation Principle of Operation Constructional Features Emf Equation & Exercise Ideal Transformer Practical Transformer Summary ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Introduction Applications Electric power systems Power transmission, Distribution Networks Electronic Circuits Electric Traction Special Applications ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Classifications No. of Phases Single Phase, Three Phase Construction Core Type, Shell Type Functional Step up, Step down Power level Power, Distribution Transformers No. of Windings One winding, Two winding, Three winding Special Transformers Instrument, Isolation, Pulse, Constant Voltage High Frequency, Phase Changing ELE 2103 Dept of E & E, MIT Manipal

N1 = Number of turns on primary N2 = Number of turns on secondary Representation Primary Side Secondary Side Core V1 Supply side V2 Load side N1 N1 = Number of turns on primary N2 N2 = Number of turns on secondary Static Device working on principle of electromagnetic induction Energy transfer from one circuit to another without change in frequency Electric Circuits linked by common magnetic core ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Operation I1 I2 Ø V1 LOAD E1 E2 V2 Magnetic Core : Flux path Flux Linkages : Primary & Secondary Induced Emf : Primary – Self Induced Emf & Secondary – Mutually Induced Emf ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Construction – Core Type LV winding Insulation HV winding Limbs Yoke Laminations Core Winding crossover Primary & Secondary windings ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Construction - Shell Type Yoke LV winding Central Limb Insulation HV winding Side Limbs Laminations Yoke Core Insulation Secondary Winding Terminals ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal emf equation ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Transformer Ratios (Transformation Ratio) N2 < N1 : Step Up type N1 N2 V1 V2 E2 < E1 V2 < V1, I1 < I2 V1 V2 N2 = N1 : 1:1 type E2 = E1 V2 = V1, I1 = I2 N2 < N1 : Step down type V1 V2 E2 < E1 V2 < V1, I1 < I2 ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Exercise [1] A 250 kVA, 11000 / 415 V, 50 Hz, single phase transformer has 80 turns on the secondary. Determine (a) rated primary and secondary currents (b) primary turns (c) maximum flux (d) emf induced per turn Ans: (a) 22.73 A, 602.41 A (b) 2120 turns (c) 23.37 mWb (d) 5.1886 Volts / turn ELE 2103 Dept of E & E, MIT Manipal

ELE 2103 Dept of E & E, MIT Manipal Summary Transformers : Importance, Applications, Classifications Two winding representation Principle of Operation Constructional Features : Core type, Shell type Emf Equation, Transformation Ratios Ideal Transformer Practical Transformer ELE 2103 Dept of E & E, MIT Manipal