Patent GB-190617786-A (GB)
Title: Improvements in connection with Elecricity Supply Systems.
Inventor: WILKINSON GEORGE
Filed: 1906-08-08
Granted: 1907-08-08
Abstract: 17,786. Wilkinson, G. Aug. 8. Distributing ; switches.-Relates to switching- apparatus for putting transformers into and out of action in an electric distribution system according to the variations of the load. Switches putting the main transformers into full action close by gravity when the load increases sufficiently, and open by the pull of an electro-magnet when the load decreases. For this purpose, use is made of an ammeter and a controlling electro-magnet which is energized by the ammeter and in turn energizes the main magnet. The controlling electro-magnet also operates a latching-lever for holding the switches in their open position. Reference is made to Specifications Nos. 2096, 11,363, and 19,749, A.D. 1904. In the arrangement shown in Fig. 3, a supplementary transformer 7, 8, in series with the main transformer 5, 6, is normally held out of action by means of switches k<3>, k<4>, which shortcircuit its secondary and primary windings respectively. An ammeter or relay 11<a> in the secondary circuit 1 allows a weighted switch lever 9 to make a circuit at 13 when the load decreases sufficiently. A small current is thus sent through a solenoid a, Figs. 1 and 3, which draws down its hollow core f and makes contact at a mercury cup g, completing a shunt circuit through the coils of a magnet e by which the switches are directly operated. Both the contact rod c and the mercury cup g are susceptible of independent adjustment relative to their mountings. The upward movement of the armature e<1> of the main magnet e opens, by means of rollers n and slotted links p<1>, a double-pole switch k', k<5> in the primary circuit, and, by lifting a bridging- contact k<3>, opens the secondary circuit also. When the armature e<1> reaches the top of its stroke, a rigidly-attached shaft m, which may carry a weight as shown in dotted lines, acts by means of a tailpiece q to open a switch h<2> in circuit with its own actuating-coils e. Just before the current is cut off, a latch r falls automatically into place below the end of the rod m, and is prevented from being forced aside under the weight of the released armature by the entry of a hook s into a notch r<3> of the latch. The hook s is moved by the downward stroke of the core of the solenoid a. At the close of these operations, the parts assume the positions shown in Fig. 3. If the current through the ammeter 11<a> subsequently increases sufficiently, the circuit of the solenoid a is broken, the hook s removed from its notch r<3> by the action of a spring t, the latch r freed, and the armature e<1> thus allowed to drop. The switch h' closes immediately, but the circuit of the magnet e is kept open by the separation of the contacts c, g. The fall of the armature e<1> recloses the switches k<3>, k<4>, k<5>, putting the transformer 7, 8 out of action. The switching- means may be utilized in other ways for controlling transformers in supply systems of the type described in the above-mentioned Specifications, as by switching transformers completely into and out of circuit. A three-wire distribution circuit may be controlled by the arrangement of switches shown in Fig. 3. With reference to Specification No. 2096, A.D. 1904, the blowing of a fuse in the circuit of the primary of the supplementary transformer may be made to open the circuit of the solenoid a and cause the windings to be shortcircuited.