High Voltage

Electrostatic Generator  Q. How does an electrostatic generator work?  Q. What is a large electrostatic generator called?  Q. Electrostatic generator working principle The drawbacks of Van de Graaff generators are that these are essentially high voltage but low power devices, and their power rating seldom exceeds few tens of kilowatts. Therefore, electrostatic generators which effectively … Read more

Van de Graaff Generator Q. With a neat sketch, explain the working of a Van-De-graff generator. What are the factors that limit the maximum output voltage obtained ? A Van de Graaff generator is a device that creates high electric potential. The Van de Graff generator was invented by Robert J. Van de Graaff, and … Read more

Electrostatic Machines Two kinds of electric energy : Static electricity and Current electricity. When an electrostatic force acts between charged particles , assign an electric potential energy, U. The difference in U of the system in two different states, initial i and final f, is ∆U = Uf  – Ui Reference point : Choose U = … Read more

Cockroft Walton Voltage Multiplier Circuit Q. Why is Cockcroft-Walton circuit preferred for voltage multiplier circuits? Explain its working with a schematic diagram. Q. Derive an expression for ripple voltage of a Multistage Cock Croft-Walton circuit. It is possible to generate very high DC voltages from single supply transformers by extending the voltage doubler circuit. This … Read more

Voltage Doubler Circuit or Cascaded Voltage Multiplier Circuit Figure A Both full wave and half wave rectifier circuits produce a dc voltage less than the ac maximum voltage. When higher de voltages are needed, a voltage doubler or cascaded rectifier doubler circuits are used. Working of Cascaded Voltage Multiplier Circuit : Suppose B is more positive with … Read more

Disadvantages of Single Phase Half wave rectifier The size of circuit is very large if high and pure dc output voltages are desired. The H.T. transformer magnitude gets saturated if amplitude of dc is comparable with the nominal a.c. of the transformer. All the above circuits are able to supply relatively low currents and therefore … Read more

Half Wave Rectifier Circuit Q. What is a half wave rectifier circuit? Q. How does a half wave rectifier circuit work? Q. What is use of half wave rectifier? Q. How is a diode used as a half wave rectifier? The simplest circuit for generation of high direct voltage is the half wave rectifier shown in figure A. … Read more

Generation of High DC Voltages Application of HVDC : Testing of cables : HVDC is used for testing HVAC cables of long lengths as these have very large capacitance and would require very large values of currents if tested on alternating voltages. In industries it is being used for. Electro-static precipitation of ashing in thermal … Read more

Ageing and Breakdown Due to Accumulative of Charges on Insulation Surface During discharges of solid or liquid or solid gas or solid-vacuum interfaces certain quantity and charge (electron) gets deposited on the solid insulator surface. Charge deposited can stay there for long durations (days and weeks) and presence of two charges increases the surface of … Read more

Solid Dielectric Used in Practice These dielectric materials are discussed in brief. 1. Organic materials Paper The dielectric constant is between 3.3 to 3.5. It is generally used for insulation purpose. The paper absorbs water, moisture rapidly i.e. it is hygroscopic, hence it is impregnated with mineral oil. The dielectric breakdown strength of paper is … Read more