Interlocking Unauthorized Actuation of High-Speed Circuit Breakers in Adjacent Feeding Lines of a DC Traction Network
Abstract
The importance of testing electronic devices for the influence of a constant magnetic field is substantiated. The magnetic field induced by Helmholtz coils having a finite rectangular cross-section is investigated. An analytical expression for the magnetic field at the axis of a finitely thick solenoid and for the magnetic field at the axis of Helmholtz coils with a rectangular cross-section is derived. In the particular case of using Helmholtz coils with a square cross-section, the condition under which the magnetic field second derivative along the system symmetry axis at the system center becomes zero is numerically analyzed, based on which the distance between the coils with a square cross-section at which the field in the system center is the most uniform is found. It is shown that consideration of coil cross-section finite dimensions results in obtaining a somewhat different optimal distance between the coils. A table of optimal distances for Helmholtz coils with a square cross-section having different thickness values has been drawn.
References
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