Transformer

Potential Transformers These transformers are extremely accurate-ratio step-down transformers and are used in conjunction with standard low-range voltmeters (usually 150-V) whose deflection when divided by voltage transformation ratio, gives the true voltage on the high voltage side. In general, they are of the shell-type and do not differ much from the ordinary two-winding transformers discussed … Read more

Three Phase Transformer Generally, electrical energy is generated in generating stations by 3-phase alternators. 3-phase system is used for transmission and distribution of Electric-energy. For stepping down or stepping up the voltage of these systems, 3-phase transformers are used. Advantages of 3-Phase Transformer over 1-Phase Transformer (For Same Capacity) Q. State the advantages of three … Read more

Industrial Applications of Transformer Q. Give industrial application of transformer. Transformer is such a important device used everywhere, where voltage from one value is to be changed to the other value. In generating stations to increase the voltage for transmission lines. In receiving stations, sub-stations to step down the voltage. In street light distribution. In … Read more

Primary of Transformer is connected to D.C. supply Q. What will happen if the Primary of the Transformer is connected to D.C. of the same Magnitude? A d.c. current will not produce the alternating flux and hence there will not be any self induced E.M.F. to oppose the supply voltage. Moreover the winding resistance is … Read more

Pulse Transformer For coupling square wave or a pulse from primary to secondary the conventional transformer need change of shape of signal. Pulse transformer is a transformer which is designed to couple pulses from primary to the load connected to secondary without changing the shape of the pulse. Pulse transformers are used for coupling pulses … Read more

High Frequency Transformers In this category we study (1) Audio frequency (AF) transformer (2) Intermediate frequency (IF) transformer. (1) Audio Frequency (AF) Transformer Audio frequency range is 20 Hz to 20 kHz These transformers are especially designed for connecting different telephone systems to each other keeping their respective power supplies ‘isolated’. Following are the functions … Read more

Comparison (similarity/difference) between Two Winding Transformer and Autotransformer Sr. No. Point of comparison Two winding Transformer Auto Transformer 1 Two types Step down and step up Similar types 2 Cost More Less 3 Construction Core and two winding Core and only one winding 4 Weight of copper Wc (1 – k) Wc  which is < … Read more

Core Cross Section For small core type transformers simple rectangular section limbs with rectangular coils are used. However for large capacity transformers circular coils are used instead of rectangular coils, as a circle gives reduced length of mean turn (due to minimum perimeter for a particular area) which reduces requirement of conductor material, which in … Read more

Transformer Core Q. Explain core, core cross section, yoke cross section of transformer. Core of the transformer is the main magnetic circuit and it offers low reluctance path for the flux. Special attention is given to core as it controls important operating characteristics such as no load current, losses, efficiency etc. hence high resistance and … Read more

Shell Type Transformer Q. Explain working of shell type transformer. In this type of transformer core covers the larger portion of windings. As shown in Figure windings are wound on central portion of the limb, which carries total flux while the side limbs completes the flux path and carry half. In this high voltage and … Read more