1. Electrical Machines LSEGG216A 9080V

2. Transformer Operation Week 2

3. Introduction Basic operation AS/NZS symbols Types Step-up, Step-down, Isolation

4. Transformer Operation V+ CIVIL VoltageCurrent Magnetic Flux

5. Transformer Operation Applied Voltage Induced Voltage Induced Voltage in Secondary Resultant Current V1V1 V’ 1 V’ 2 IMIM

6. Induced Voltage Φ max =Maximum instantaneous flux F = Frequency N = Number of turns B max = Maximum permissible flux density in Wb A = CSA of core in m 2

7. Transformer Operation V1V1 IMIM IeIe IoIo I e = Iron loss current I o = No load current

8. V1V1 V’ 1 V’ 2 IoIo I’ 2 I’ 1 I1I1

9. Transformer Operation V1V1 V’ 1 V’ 2 IoIo I’ 2 I’ 1 I1I1

10. Transformation Ratio Magnetic flux is common coils Therefore the voltage can be varied by changing the number of turns

11. V1=V1=N1N1 N2N2 V2=V2= = k = Transformation Ratio

12. Transformation Ratio V 1 x I 1 N1N1 N2N2 =V 2 x I 2 = I1I1 I2I2

13. Transformation Ratio V 1 x I 1 VA V 2 x I 2 kVA Power InPower Out

14. Transformation Ratio V 1 x I 1 V 2 x I 2 200  200V100V 800  K = 2

15. Transformer Basic Tests Open Circuit Test Short Circuit Test Oil Tests Electrical Insulation Polarity Continuity

16. Open Circuit Test Used to determine Iron Losses Supply = Rated Voltage

17. Wattmeter reading V1V1 IMIM IoIo IeIe Supply Voltage Ammeter reading

18. Short Circuit Test Used to determine Copper Losses Supply Adjusted = Rated Secondary Current