Skip to main content

Posts

Three Phase Transformer , Autotransformer

Three Phase Transformer Three phase transformers are used throughout industry to change values of three-phase voltage and current. Since three-phase power is the most common way in which power is produced, transmitted, and used, an understanding of how three phase transformer connections are made is essential. A three phase transformer is constructed by winding three single phase transformers on a single core. These transformers are put into an enclosure which is then filled with dielectric materials such as air, plastic or oil. The dielectric material performs several functions. Since it is a dielectric, a non-conductor of electricity, it provides electrical insulation between the windings and the case.  It is also used to help provide cooling and to prevent the formation of moisture, which can deteriorate the winding insulation. Three-Phase Transformer Connections Three-phase transformers can consist of either three separate single-phase transformers, or three winding
Recent posts

Single Phase Transformer

In this article,you will find the study notes on  Single Phase Transformer   which will cover the topics such as  Ideal Transformer,Equivalent Circuit of Ideal Transformer,Referred Parameter,Transformer Losses, Efficiency of Transformer,Open Circuit Test & Short Circuit Test,Voltage Regulation of Transformer. A basic transformer consists of two separate windings of insulated wires wound around a common iron core. The power source or supply is hooked to the primary winding, the load to be served is hooked to the secondary winding. Primary windings, connected to the alternating voltage source, and Secondary windings, connected to the load. Iron core used to link the flux in both windings. When the primary winding is energized an electromagnetic field builds up and then collapses in the iron core, this field cuts through the secondary coil winding inducing power to the load hooked to the secondary. This power buildup and collapse is called magnetic flux and occurs at a freque

DC MACHINES

INTRODUCTION DC machine is a highly versatile and flexible machine. It can satisfy the demands of load requiring high starting, accelerating and retarding torques. If the conversion is from mechanical to electrical energy, the machine is called as Generator. If the conversion is from electrical to mechanical energy, the machine is called as Motor. Types of DC Machines: The types of DC machine depends upon the excitation of DC machine. The production of magnetic flux in the machine by circulating current in the field winding is called excitation. DC Machines can be classified according to the electrical connections of the armature winding and the field windings. There are two methods of excitation namely, separate excitation and self-excitation. In separate excitation, the field coils are energised by a separate DC source. The terminals of the winding can be connected across the input voltage terminals or fed from a separate voltage source. In self-excitation, the cur