Computation of the self-induced magnetic field in circuit-breaker arcs

1997 ◽  
Vol 25 (5) ◽  
pp. 974-981 ◽  
Author(s):  
H. Pellegrin ◽  
J.-Y. Trepanier ◽  
R. Camarero ◽  
Xu Dong Zhang
Keyword(s):  
Magnetic Field ◽  
Circuit Breaker ◽  
The Self ◽  
Induced Magnetic Field

The influence of the self-induced magnetic field in circuit breaker arcs

1996 ◽  
Author(s):  
H. Pellegrin ◽  
J.-Y. Trepanier ◽  
R. Camarero ◽  
X. Zhang
Keyword(s):  
Magnetic Field ◽  
Circuit Breaker ◽  
The Self ◽  
Induced Magnetic Field

Paper 33: Heat Transfer Effects Arising from arc Rotation in Plasma Arc Heaters of the Self-Induced Magnetic Field Type

1965 ◽  
Vol 180 (10) ◽  
pp. 1-15
Author(s):  
E. A. Bunt ◽  
H. L. Olsen
Keyword(s):  
Magnetic Field ◽  
Aerodynamic Drag ◽  
Input Power ◽  
Turbulent Pipe Flow ◽  
Supersonic Combustion ◽  
The Self ◽  
Fourth Power ◽  
Stagnation Temperature ◽  
Induced Magnetic Field ◽  
Electrode Gap

This paper is concerned with an analysis of the thermal behaviour of high input power (∼ 15 megawatt) arc heaters operating at values of total (bulk) enthalpy up to 2500 Btu/lb. Such heaters are currently in use to supply air for aerodynamic testing purposes, including subsonic turbulent pipe flow, the operation of propulsion tunnels with ‘full’ temperature simulation, and supersonic combustion ducts. The electrode system is essentially a ‘rail accelerator’ adapted for continuous operation by making it re-entrant, the self-induced magnetic field bringing about rapid movement of the arc roots to prevent destruction of the electrodes. The rate of rotation of the arc column (which is subject to aerodynamic drag) is shown to be a function of apparent electrode gap, current, and the stagnation temperature and pressure in the arc chamber. A distinction can also be drawn between ‘long’ and ‘short’ arcs, depending on whether the inter-electrode gap is large or small. The value of the arc rotation rate ω (which ranges between approximately 50 and 1000 per sec) has a considerable bearing on the thermal efficiency of short-gap arcs, on account of the dependence on it of the convective losses. Since the chamber gases radiate much more strongly than air uncontaminated by electrode material, convective and radiative losses are distinguished by solving for first-power and fourth-power dependence on temperature difference with the walls; the convective losses are examined in conjunction with a vortex model of the gas behaviour.

scholarly journals Magnetic Properties of Structural Steels for Simulation of Crack Monitoring by Finite Element Method

2019 ◽  
Vol 39 (1) ◽  
Author(s):  
Menno Patrick van der Horst ◽  
Miroslaw Lech Kaminski
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Relative Permeability ◽  
The Self ◽  
Magnetic Flux Leakage ◽  
The Finite Element Method ◽  
Induced Magnetic Field ◽  
Flux Leakage ◽  
Element Method

AbstractThe metal magnetic memory method is a novel technique for monitoring fatigue cracks in steel structures, which can reduce operational expenses and increase safety by minimizing inspections. The crack geometry can be identified by measuring the self magnetic flux leakage, which is induced by the Earth’s magnetic field and the permanent magnetization. The finite element method can be used to simulate the induced magnetic field around cracks to help interpret the self magnetic flux leakage measurements, but it is unclear what material properties to use. This study aims to determine the magnetic permeability of structural steel for accurate simulation of the induced magnetic field around cracks by the finite element method. The induced magnetic field was extracted from measurements above two square steel plates, one without defect and one with a straight slit, and compared with finite element results in function of the relative permeability. For both plates, a uniform relative permeability could be found for which experimental and numerical results were in good agreement. For the plate without defect and a relative permeability of 350, errors were within 20% and were concentrated around the plate’s edges. For the plate with the slit and a relative permeability of 225, errors were within 5%.

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