GB402729A - Improvements in quick-acting switches for heavy current - Google Patents

Abstract

402,729. Automatic circuit-breakers. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.- (Assignees of Allgemeine Elektricitats-Ges.; 2, Friedrich Karl-Ufer, Berlin.) Feb. 29, 1932, No. 6108. Void [Abridged as open to inspection under Sect. 91 of the Acts, Feb. 28, 1932]. [Class 38 (v).] In a D.C. circuit-breaker of the type in which a conductor carrying the main current is adapted on overload to cause a diversion of flux from the armature to such an extent that the armature is released to interrupt the circuit, the coils of the holding electromagnet are disposed in groups between which is disposed the main current winding. As shown in Fig. 1, the magnetic circuit consists of an armature 1, intermediate members b and a yoke h separated from the members b by air gaps i. The energizing coils carried by the members b are divided into two groups f, g between which is disposed a transverse core k carrying a conductor l in parallel with a magnetic shunt m in the main circuit, excessive current in conductor l weakening the holding flux in armature a which is raised by its spring d to open the circuitbreaker c. The circuit-breaker may also be opened on a prolonged overload of insufficient value to release armature a by the operation of a time-lag relay o which opens the supply circuit of coils f, g. The circuits of coils f, g may be arranged as shown in Fig. 2 in which a resistance r is inserted in the coil circuits for maintaining the auxiliary armature in its attracted position by contacts h, q operated by the circuit breaker. Reclosure is effected by a switch o<1>. The sets of coils f, g may be disposed on the members b so that the main conductor l can be introduced between, thus permitting a narrow construction of circuitbreaker to be made. To equalise the current in the two groups of coils calibration resistances may be connected in parallel.