Methods of increasing the surface flashover potential in vacuum

Author

Hatfield, L.L. ; Boerwinkle, E.R. ; Leiker, G.R. ; Krompholz, H. ; Korzekwa, R. ; Lehr, M. ; Kristiansen, M.

Author_Institution

Dept. of Phys., Texas Tech. Univ., Lubbock, TX, USA

Volume

24

Issue

6

fYear

1989

fDate

12/1/1989 12:00:00 AM

Firstpage

985

Lastpage

990

Abstract

The effects of surface coating and magnetic fields on dielectric surface breakdown in vacuum are described. Coatings of metals and meta oxides increase the pulsed surface hold-off voltage by factors of up to three, depending on the material. Measurements of the secondary emission coefficient show substantial differences between coated and uncoated samples at high energies. The influence of magnetic fields on dielectric surface breakdown for uncoated samples is investigated in the pressure range of 10^-5 to 1 Pa, for both DC and pulsed electric and magnetic fields. Insulation effects (increase in breakdown voltage of up to 2× at magnetic field amplitudes of 0.5 T) are observed when the magnetic field is parallel to the surface of the dielectric and perpendicular to the applied electric field. Magnetic insulation shows a strong material dependence and decreases with increasing pressure and surface roughness

Keywords

flashover; magnetic fields; surface discharges; 1E-5 to 1.0 Pa; DC; applied electric field; coated samples; dielectric surface breakdown; magnetic fields; magnetic insulation; pulsed; pulsed surface hold-off voltage; secondary emission coefficient; surface coating; surface flashover potential; surface roughness; uncoated samples; vacuum; Coatings; Dielectric breakdown; Dielectric materials; Dielectrics and electrical insulation; Flashover; Magnetic field measurement; Magnetic materials; Rough surfaces; Surface roughness; Vacuum breakdown;

fLanguage

English

Journal_Title

Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

0018-9367

Type

jour

DOI

10.1109/14.46324

Filename

46324