Part I Transformers and Electrical Machines – Transformers – Introduction – Transformer Equations – Basic Electromagnetic Description and Equations – Phasor Equations and Equivalent Circuit for – Sinusoidal Supply – Referred Values: Equations and Equivalent Circuit – PerUnit Description – Construction and Scaling Laws – Specific Rated Quantities – Rated PerUnit Impedances – Alternative and Simplified Equivalent Circuits – NoLoad Operation – ShortCircuit Operation – ShortCircuit Impedance – Procentual ShortCircuit Voltage – Remarks – Voltage Variation with Load – Parallel Operation of Transformers – Construction of SinglePhase and ThreePhase Transformers – SinglePhase Transformers – ThreePhase Transformers – Connection and Vector Group of a ThreePhase – Transformer – Winding and Terminal Markings – Modelling of a ThreePhase Transformer – Connections and Vector Groups – Asymmetrical Operation of Phase – Transformers – Autotransformer – PhaseNumber Transformation – Three to Six or Twelve Phases – Three to Two Phases – Voltage Regulation Transformers – Measurement Transformers – Current Transformers – Voltage Transformers – Direct Current Commutator Machines – Introduction – Construction of the DC Machine .