# Elektrodynamika aparatów elektrycznych

## Data

2007

## Autorzy

## Tytuł czasopisma

## ISSN czasopisma

## Tytuł tomu

## Wydawca

Wydawnictwo Politechniki Łódzkiej

Lodz University of Technology. Press

Lodz University of Technology. Press

## Abstrakt

Technical electrodynamics is concemed with the interaction between
magnetic and electric fields on electrical devices, and with the analysis of
electrodynamic forces in particular. This monograph presents the electrodynamics
of selected electrical devices and apparatus - switching devices, driving
electromagnets of apparatus, current limiting devices. Calculations of electrodynamic
forces are important as a current flowing through a switching device
during a short circuit may be hundreds times higher than its rated current, so
electrodynamic forces can be tens of thousands higher than those under rated
operational conditions. It may result, among others, in electrodynamic contact
repulsion, and contact sticking making the further operation of a switching
device impossible. Moreover, calculations of electrodynamic forces are necessary to
determine the cross section of current conductors, span length, and to select the
way of fastening current paths, and also to determine the number and the
strength of supporting structures and fastening elements. The second and partly
the third chapters cover the survey of formulas and methods for calculating
electrodynamic forces on contacts and current paths of switching devices. For
this case, the analysis of electrodynamic forces applies mostly to the pass
current duty of switching devices. The knowledge of magnetic fields and
electrodynamic forces is,Atecessary to analyze the phenomenon of arc e
xtinguishing resulting. from arc motion on the contact-extinguishing system of
a switching device during its commutating duty. The arc motion speed, which is
dependent, among others, on the electrodynamic force effecting this motion,
influences the course of arc voltage, arcing time, and energy released in arc, so
influences also the electrical endurance and reliability of a switching device.
The analysis of arc motion speed makes it possible to evaluate contact materials,
arc runners, and extinguishing chambers, and also approximately the switching
capacity of an extinguishing system. Therefore, the great part of Chapter 3, and
Chapter 4 of this monograph describe electrodynamic forces acting on the root
and the column of an arc that bums between contacts and on arc runners. The
given examples for calculation of electrodynamic forces and for simulation of
arc motion agree with the results of experimental investigations carried out with
use of an ultra-high-speed film camera. Chapter 5 presents the broad theoretical
description of electrodynamic forces acting on an arc root on ferromagnetic
plate of extinguishing chamber being different in shape, without and with a
cut-out. The calculations of arc motion trajectory made by the mirror reflection
method, and measurement results verifying these calculations, taken as
examples from the literature, have been collated by the author with the results of
his own calculations based on the finite-element and boundary-element
methods. The author's research has shown that such arc stop finał places can
exist that are different from those given in the literature. Chapter 6 illustrates the
possibilities of practical application of theoretical considerations gi ven in the
foregoing chapters. Chapter 7 covers the analysis of forces developed by DC
and AC electromagnet drives broadly used on electrical apparatus. Considering
methods for calculating electromagnets described in the literature, the example
analyses are given carried out with the author's computer programs and the
commercial ones. The results of computer simulating the operation of a selected
AC electromagnet in relation to an angle, at which a coil supply voltage is
switched on, are compared with mcasurement results derived with use of an
automated computerized test system. The finał chapter of this monograph
presents new, high-class constructional solutions of electrical apparatus
developed by scientists and designers competently employing the existence of
electrodynamic forces. Designing such apparatus becomes easier with use of the
descriptions of electrodynamic forces which were earlier elaborated and
afterwards suitably developed.

## Opis

Seria Wydawnicza - Postępy techniki wysokich napięć t. 27

## Słowa kluczowe

elektrodynamika, urządzenia elektryczne, łuk elektryczny - modele matematyczne, aparaty elektryczne, electrodynamics, electrical devices, electric arc - mathematical models, electrical appliances

## Cytowanie

Tarczyński W., Elektrodynamika aparatów elektrycznych., Wydawnictwo Politechniki Łódzkiej, Łódź 2007, ISBN 978-83-7283-239-9.