ABSTRACT
Electric power transformers are static devices, made of ensembles of electric and magnetic circuits which step-up or step-down the a.c. input voltage (single or multiphase) to transmit the input power minus losses (core and winding losses), based on Faraday (electromagnetic induction) Law. Transformer transients such as inrush current, sudden short-circuit, dynamic forces and transformer behavior (model) for ultrafast voltage pulses (of commutation and of atmospheric nature) have been given special quantitative analysis with case studies. The core is earthed, in general, in one point. The magnetic core made of thin insulated lamination layers is glued together for small power and wrapped with steel straps around the limbs or epoxy-cured stacked for large powers. Holes through the lamination core are to be avoided to reduce additional losses. Clamps with curved tie bolts keep the yoke laminations tight.
