Vacuum Breakdown: In the Townsend type of discharge in a gas described earlier, electrons get multiplied due to various ionization processes and an electron avalanche is formed. In a high Vacuum Breakdown, even if the…
Vacuum Insulation: The idea of using Vacuum Insulation purposes is very old. According to the Townsend theory, the growth of current in a gap depends on the drift of the charged particles. In the absence…
Gases and Gas Mixtures for Insulation Purposes: Over the years, considerable amount of work has been done to adopt a specific gas for practical use. Before adopting a particular gas or gas mixtures for a…
Post Breakdown Phenomena in Gases: This is the Post Breakdown Phenomena in Gases which occurs after the actual breakdown has taken place and is of technical importance. Glow and arc discharges are the Post Breakdown…
Breakdown in Non Uniform Fields: In Breakdown in Non Uniform Fields, such as coaxial cylinders, point-plane and sphere-plane gaps, the applied field varies across the gap. Similarly, Townsend's first ionization coefficient (α) also varies with…
Corona Discharges: If the electric field is uniform, a gradual increase in voltage across a gap produces a breakdown of the gap in the form of a spark without any preliminary discharges. On the other…
Paschen Breakdown | Paschen's Law | Paschen curve It has been shown earlier (refer Sec. 2.6) that the Paschen Breakdown criterion in gases is given as where the coefficients α and γ are functions of E/p, i.e…
Streamer Theory of Breakdown in Gases: Townsend mechanism when applied to breakdown at atmospheric pressure was found to have certain drawbacks. Firstly, according to the Townsend theory, current growth occurs as a result of ionization…
Formative Time Lag: Formative Time Lag - In the previous section, the mechanism of spark breakdown is considered as a function of ionization processes under uniform field conditions. But in practical engineering designs, the breakdown…
Experimental Arrangement to Measure Ionization Coefficients α and γ: The Experimental Arrangement to Measure Ionization Coefficients is shown in Fig. 2.2. The electrode system consists of two uniform field electrodes. The high voltage electrode is connected…
