Patent GB-190726834-A (GB)
Title: Improvements in Apparatus for Producing High Frequency Electric Discharges.
Inventor: HADDAN HERBERT JOHN
Filed: 1907-12-04
Granted: 1908-04-16
Abstract: 26,834. Haddan, H. J., [Synchronous Static Co.]. Dec. 4. High -frequency oscillatory discharges, producing; induction coils; switches.-In a method of producing high-frequency electric discharges by the use of either alternating or direct current, the two windings of an induction coil are connected in series with the supply-circuit when direct current is used, or one winding is connected to the supply-circuit and the other to the circuit charging the condenser when alternating current is used. In the arrangement shown in Fig. 1, the discharge-circuit of the condenser 4 includes the primary 3 of the high-tension transformer 2, and an interrupter 5, which comprises a tensioned-ribbon carrying the armature 9 of the magnet 10, having a core of laminated soft iron polarized by a permanent magnet consisting of two members 13 interlocking with the core 12. The induction coil 14 has a closed iron core 17 with two windings 15, 16, each comprising a pair of coils wound on the two legs of the core. The ends of these coils are connected to the contacts of a change-over switch 18 ; and the connexions are such that, when the switch 18 is in the position shown for use with an alternating supply, both windings 15, 16 produce a magnetic flux in the same direction in a closed magnetic circuit, but, when the switch 18 is reversed for a direct-current supply, the coils 15, 16 act oppositely on the core, the upper part being polarized in the opposite direction to the lower half, so that the core thus acts as an open magnetic circuit, giving a sharp discharge on breaking the energizing circuit. When alternating current is used, the switch 18 is placed in the position shown in Fig. 1, so that current flows from the lead 45 through wires 47, 69, and windings 15 in series, to the return lead 44. The current induced in the secondaries 16 flows from the upper coil 16 through the interrupter magnet 10, interrupter 5, contact 7 or 8, contact 25, switch 42, impedance 39, lower coil 16, and through the switch contacts back to the upper coil. When the contact 7 or 8 is broken by the magnet 10, the condenser 4 is charged and then discharged through the primary 3 of the transformer 2. A charge and discharge of the condenser occurs when the interrupter leaves both the front and back contacts 7, 8. When direct current is used, the contact 8 is put out of action and the switch 18 moved to engage contacts 28, 31, 34, 37. Current then passes from the wire 45 through the wire 47, contact 7, interrupter 5, magnet 10, coils 16, wire 55, impedance 39, coils 15, and wire 48 back to the wire 44. At each operation of the interrupter, the condenser 4 is charged and discharged as before. In the modification shown in Fig. 3, the induction device 60 is wound so that the coils 67, 68 act in similar directions both with alternating and direct currents, and the open magnetic circuit, which is desirable for obtaining the proper discharge with direct current, is obtained by forming the core 61 with a bridge 62 adapted to be moved to make an open or closed magnetic circuit. A switch 63, operated by the movement of the bridge 62, completes a circuit through the coils 67 when alternating current is used, and also a charging circuit through the coils 68, impedance 39, interrupter 5, and magnet 10 as before. When the contact 63 is open for direct - current working, a circuit is completed through the interrupter and coils 10, 68, 39, 67 in series. The core 61 and bridge 62 are laminated and interlocked by grooves, as shown in Fig. 4, to decrease the reluctance. In a further modification, a switch 73, Fig. 5, is provided for connecting the supply wire 47 to the interrupter 75 for using direct current, or to the coil 74 for alternating current. The induction device has a keeper 81, which may be removed to give a quick discharge when using direct current. The interrupter magnet 10 is energized by the currents induced in the secondary coil 76 by the interruptions of the direct current at the interrupter 75.