Patent GB-190815047-A (GB)
Title: Improvements relating to Alternating Electric Current Distribution Systems.
Inventor: PECK JOHN SEDGWICK
Filed: 1908-07-15
Granted: 1909-07-15
Abstract: 15,047. Peck, J. S. July 15. Distributing.-A fuse, placed in the auxiliary transformer circuit of a transformer distribution system, is arranged to short-circuit the windings of the auxiliary transformer in a series system, or to place the auxiliary transformer windings in parallel with the main transformer windings in a parallel system, when the current in the auxiliary transformer exceeds a predetermined amount, by releasing a spring or weight. A circuit containing a visible or audible signal may also be closed by the action of the fuse and spring or weight, while the circuit of the coil arranged to electromatically open the switch is opened. In the arrangement shown in Fig. 1, the windings 3, 4 of the main transformer 1 are adapted to be connected in series with the windings 5, 6 of the auxiliary transformer 2 by means of a switch 14, the coils 18, 19 of which are controlled by the action of a relay 26. The coil 29 of the relay 26 is energized from the secondary winding 30 of a transformer 31, a portion of the primary of which is short-circuited by the contact 16 of a switch 15, which also short-circuits the primary winding 5 of the transformer 2. When the load upon the system is light, the relay and switches occupy the position shown, but, when the load increases to a predetermined value, the relay 26 closes the circuit of the coil 18, thereby causing the latter to short-circuit the windings of the transformer 2. When the load falls, the spring 28 causes the relay 26 to close the circuit of the opening-coil 19. In the circuit of the auxiliary transformer 2, a fuse 41 is placed, which, when blown, causes the arm 38 of a bell-crank lever 37 to release an arm 34 operated by a weight 36, to close the switches 14, 15 and, if required, a circuit containing an indicating-lamp 23 or an audible signal. The arm 34 also breaks the circuit of the opening coil 19 at the contact 20, so that the switches 14, 15 cannot be opened until the fuse 41 has been replaced. In a parallel system of distribution, the switches 14, 15 are adapted to close the main transformer windings in parallel with the auxiliary transformer windings when the load increases, and vice versa. In the arrangement shown in Fig. 3, the auxiliary transformer connexions are arranged as described in Specification No. 8377, A.D. 1908, while the arrangements for opening and closing the switches 14, 15 and operating the arm 34 are similar to those shown in Fig. 1. A three-wire parallel transformer distribution system is shown in Fig. 4, in which the main transformer is divided into two equal portions 42, 43, the adjacent ends of which are connected to fixed terminals 12, 13 of the switch 14 having its movable contact 45 connected to the neutral wire 44. The arrangements for operating the switches 14, 15 and the arm 34 are similar to those shown in Figs. 1 and 3. According to the Provisional Specification, the current in the coil 29 of the relay 26 may be reduced by placing it in parallel with a choking- coil, the magnetic circuit of which is arranged to become saturated when the current through the coil reaches a predetermined value, while the choking-coil may be arranged to be connected in circuit when the switch 14 is closed ; or the switch 14 may be arranged to short-circuit a portion of the turns of the magnet 29.