GB1057070A - Electrical resistance devices - Google Patents

Abstract

1,057,070. Conducting - liquid switches. ETABLISSEMENTS MERLIN & GERIN, SOC. ANON. Dec. 3, 1963 [Dec. 12, 1962], No. 47607/63. Heading H2B. [Also in Division H1] A liquid resistance intended for connection with an isolating switch in parallel with a circuit breaker such that when the breaker opens the resistance presents a low value, the subsequent current surge causing the formation of an insulating film on the resistance electrodes due to the gas bubbles generated whereby the resistance presents a high value enabling the shunt circuit to be opened by the isolating switch, comprises a stack of insulating receptacles 14 forming spaces therebetween containing conducting liquid L, each receptacle having an electrode 15. To prevent arcing between the electrodes baffles 16, 17 may be provided. The liquid L may be sulphuric acid and in order to enhance the gas formation so that the electrodes 15 are insulated by the bubbles for a longer period of time, material may be introduced into the liquid which liberates gases under the action of heat, e.g. colloidal carbon or ammonium sulphate. The stack may be mounted in a gasfilled insulating tube (not shown). In a modification (Fig. 4, not shown) the receptacles 20 are metallic and themselves serve as electrodes at positions opposite openings 23, 24 in lower and upper insulating layers 22, 21. The material of the layers 22, 21 may evolve gas under the action of heat at the openings 23, 24. In another modification (Fig. 5, not shown) the electrodes 15 are in line and the insulating receptacles 14 are separated from one another by porous partitions 25 which are permeable to the conducting liquid L but impermeable to the gas bubbles.