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Electrical Machines. LSEGG216A 9080V. Transformer Operation. Week 4 . Transformer Operation. CIVIL. V+. Voltage. Current. Magnetic Flux. Transformer Operation. Applied Voltage. Induced Voltage. V’ 2. V’ 1. V 1. Induced Voltage in Secondary. I M. Resultant Current. - PowerPoint PPT Presentation

### Transcript of Electrical Machines

• Electrical MachinesLSEGG216A9080V

• Transformer OperationWeek 4

• Transformer OperationV+CIVILVoltageCurrentMagnetic Flux

• Transformer OperationApplied VoltageInduced VoltageInduced Voltage in SecondaryResultant CurrentV1V1V2IM

• Induced Voltagemax =Maximum instantaneous fluxF = FrequencyN = Number of turnsBmax = Maximum permissible flux density in WbA = CSA of core in m2

• Transformer OperationV1IMIeIoIe= Iron loss currentIo = No load current

• Transformer OperationV1V1V2IoI2I1I1

• Transformer OperationV1V1V2IoI2I1I1

• Transformation RatioMagnetic flux is common coilsTherefore the voltage can be varied by changing the number of turns

• Transformation RatioV1=N1N2V2== k= Transformation Ratio

• Transformation RatioV1x I1N1N2=V2 x I2=I1I2

• Transformation RatioV1x I1VAV2 x I2kVAPower InPower Out

• Transformation RatioV1x I1V2 x I2200200V100V400K = 2

• Voltage RegulationEIVoltage Drop Due to RVoltage Drop Due to XLVResistanceInductanceCoils have both

• Voltage RegulationEIVLagging PF of 45V less than E

• Voltage RegulationEIVLeading PF of 45V More than than E

• Voltage Regulation100 x VNo Load V Full LoadVFull LoadR% =If PF = Unity100 x I x (R x cos + XL x sin)VFull LoadR% =

• Transformer Basic TestsOpen Circuit TestShort Circuit TestOil TestsElectrical InsulationPolarityContinuity

• Open Circuit TestUsed to determine Iron LossesSupply = Rated Voltage