Patent GB-605163-A (GB)
Title: Improvements in or relating to gas-blast electric circuit-breakers
IPC: H01H33/56
Filed: 1945-12-17
Abstract: 605,163. Gas-blast switches. REYROLLE & CO., Ltd., A., ALLAN, A., and BLANCH, N. R. Dec. 17, 1945. No. 34098. [Class 38 (v)] The contacts of a pneumaticallyactuated, gas - blast circuit - breaker are enclosed in a reentrant cell which extends into the air reservoir, communication between the reservoir and cell being controlled by the blast valve. In Fig. 2 a conducting- ring C connected to one pole of the breaker is mounted in an insulating cylindrical-cell B located in a reservoir A, the cell being closed at its lower end by an endcap unit D incorporating the fixed arcing-contact D<2>, blast-valve D<1> and fixed isolator-contact Fl. Two pistons F3, F<4> are mounted in a cylinder F<2> which is arranged in the reservoir A and provided with three pilot - valves (not shown), so arranged at its ends and centre, respectively, that both sides of the pistons F3, F<4> are normally under pressure. The breaker is opened when a trip-coil operates one of the pilot-valves so as to exhaust the R.H. side of the piston F<3>, and thereby operate a spring-loaded valve F<5> controlling the blast-valve D<1>. Compressedair thereupon flows in to the cell B and moves an arc-initiating contact B<5> away from the arcing-contact D<2>, the arc being blown through a nozzle B<3> attached to an insulating-cylinder B<2>, on to an arcing-electrode B<7>, and exhausted through a baffle B<6> and non-return valve A<2>. The isolator F is opened when an auxiliaryswitch (not shown) actuated by the valve F <5>, energizes a coil controlling the second pilotvalve, and exhausts the L.H. side of the piston F<4>. A second auxiliary-switch actuated simultaneously with the isolator, de-energizes the trip-coils, whereupon the valves F<5>, D<1> close and the contact B<5> is returned by its spring. The isolator is re-closed by energizing a coil controlling the third pilot-valve and exhausting the space between the pistons F<3>, F<4>. A resistance B<8> is wound on the cylinder B<2> and is connected to the contact D<2> via a contact B<9> on the cylinder B<2>, and a contact B<10> on the cell B. The contact D<2> is detachably mounted on the end-cap unit D, so that the cylinder B<2>, together with the contacts, nozzle and resistance may be withdrawn through the end of the cell B by detaching the valve A<2>. In Fig. 7 (not shown), two series-connected breaking-gaps are arranged in separate cells in a common reservoir, and the two blast-valves are controlled simultaneously by a common pilot-valve, the fixed contacts being inter-connected by a rotary-bar isolator, which engages an earthing contact in the open position. A resistance may be connected across one or both gaps. In Figs. 8, 10, two series-connected gaps are arranged in a single cell, fixed arcing-contacts L\ L<2> cooperating with nozzles K<1>, K<2> and an arcing- electrode M. S-shaped contact blades P engage the contacts L\ L<2> and are mounted on a vane P<1>, one side P<2> of which is exposed to the airpressure within the cell, whilst the other side P<3> is exhausted through a tube P<4>, which encloses a contact-closing torsion-rod p to which the vane P<1> is attached. An isolator F<8> is arranged in the reservoir A<6>