Investigation and optimization of magnetron discharge in a vacuum switch

Abstract

Vacuum interrupters and switches are sealed for life. In order to guarantee the vacuum integrity, an accurate and reproducible gas pressure measurement is mandatory. This is performed in production on each vacuum interrupter and switch as a routine test. This is a part of the quality processes and tests applied to those devices during the production that ensure the excellent quality and guarantee more than 30 years shelf life. The pressure measurement technique is based on the magnetron effect. The basic phenomenon is an electron trap in crossed electric and magnetic field. The electrons are trapped radially by the magnetic field and axially by the electrostatic field. In the frame of this work, we have investigated with different approaches the electron trap. It was performed with analytic approach, 2 dimensional and 3 dimensional simulations. Using those results, we have tested different designs of switches in order to compare the low pressure discharge signals. Some theoretical and experimental results are presented.