ELECTRIC STRENGTH OF VACUUM-SYSTEMS WITH CO-MO ALLOY COATED CU ELECTRODES

The paper presents the results of investigations of the electric stren gth at 50 He ac voltage of vacuum insulation systems that were not sub jected to conditioning. The experiments have shown that a Co-Mo alloy coating electrolytically deposited on the surface of copper electrodes causes, at the pressure 2 mPa, > 25% increase of electric strength of unconditioned vacuum insulation systems. This breakdown strength decr eases with increasing gap spacing between the electrodes, and amounts similar to 17 kV/mm for systems with Cu electrodes at the electrode ga p of 1 mm, and similar to 9 kV/mm at a gap of 6 mm. Plane electrodes w ith rounded-off edges of Rogowski's profile were used in the investiga tions. The electrodes with 50 mm diameter, were made of OFHC Cu. The p aper shows the influence of the value of pressure from similar to 1 mP a to 1 Pa and at constant pressure of similar to 1 mPa, the length of vacuum gap, and the presence of a Co-Mo alloy layer coating the electr odes.