CORONA ONSET VOLTAGE OF INSULATED AND BARE ELECTRODES IN RAREFIED AIR AND OTHER GASES
Abstract
Electrical discharges caused by corona, glow discharges, and voltage breakdown were measured under conditions encountered in the X-20A (Dyna-Soar) aerospace vehicle when operating within the 70,000-to 250,000-ft altitude zone. Most measurements were made at the electric-power-system frequency (400 hertz) in gases used to pressurize X-20A compartments. These gases were nitrogen, oxygen, notrogen-oxygen mixtures, and normal sea level air at reduced pressure. Test results show that: (1) the corona onset voltage (that voltage at which the electrical discharge is initiated) can be increased by insulating the electrical terminals and by twisting or cabling the insulated wires; (2 the corona onset voltage between insulated wires is increased as the insulation is made thicker and insulation dielectric constant is made lower, and is decreased to that of bare wires as the wire diameter and wire spacing are increased; and (3) the corona onset voltage of components depends on the type of component, its wire connections, its installation, and the gaseous environment. The corona onset voltage of round, bare, nichrome wires is less at temperatures over 500 C than at temperatures between -60 C and 150 C. The corona onset voltage drops to nearly zero when contaminants such as molybdenum-trioxide vapor permeate the air space between wires at temperatures above 500 C and pressures above 1.0 torr.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1966
- Accession Number
- AD0483820
Entities
People
- William G. Dunbar
Organizations
- Boeing