GB813946A - Improvements for or relating to electromagnetic switching control devices - Google Patents

Abstract

813,946. Electromagnetic switches. BRISTOL CO. Feb. 5, 1957 [Feb: 10. 1956], No. 3942/57. Class 38 (5). A synchronous contactor similar to that of Specification 703,772, wherein a pair of contactcarrying armatures 24, 25 are energized by a magnet structure 15, 16, 19 and electromagnet 20, 21 energized by A.C. so as to oscillate between contacts of respective pairs 32, 34 and 33, 35, is provided with a closed loop 37, around one of its armatures 24 so as to delay its operation with respect to the other. The loop may alternatively comprise a winding in series with an adjustable resistance to allow variation of the amount of contact lag. With the moving contacts 26, 27 interconnected by external means and the operating coil 21 energized through a phase-shifting transformer (Fig. 9, not shown) it is possible to arrange the circuit as in Fig. 6 such that with an input voltage applied to terminals E, a measure of the peak voltage of the wave is obtained as a series of pulses at terminals C. The contacts 32, 35 may be connected to separate terminals A, B (Fig. 2) so that positive and negative output may be separated. In Fig. 7 the loop 37 delays the contact 26 so the contactor acts as a single-pole, make-before-break, change-over switch. The moving contact structure is connected to a terminal H whereby output circuits are closed alternatively between H, F and H G with a slight overlap due to the delay.