Patent GB-190314175-A (GB)
Title: Improvements in Gas or Vapour Electric Apparatus, such as Mercury Vapour Lamps and Converters for Lighting or other purposes.
Inventor: TALL FREDERICK WILLIAM LE
Filed: 1903-06-25
Granted: 1904-06-25
Abstract: 14,175. Le Tall, F. W., [Cooper-Hewitt Electric Co.]. June 25. Vacuum tubes.-When apparatus of the mercuryvapour lamp or converter type is operated on an alternating-current circuit, means are provided for applying a starting electric pressure to break down the negative electrode reluctance, and other means, such as an inductance for maintaining the current through the apparatus during the intervals between successive current impulses. In the use of single-phase currents, the current during the first alternation after starting does not rise sufficiently to allow the inductance to perform its function properly at the first interval, and means are therefore provided for applying an extra pressure to the apparatus, at starting only, to produce a larger current than would otherwise flow. In the arrangement shown in Fig. 1, the starting pressure is obtained from a transformer 11 having its secondary 12 in series with the inductance 7 between the negative electrode 5 and a starting-band 6. A spark-gap 35 in this circuit serves for adjustment of the phase difference between the main pressure, applied between a positive electrode 2, 3 and the negative electrode 5, and the starting pressure. When the apparatus lamp 1 is in operation, the inductance 7 discharges through one half of the auto-transformer coil 21, one of the leads 9, 10 and anodes 3, 2, and the con. tainer 1, to maintain the current as stated above. The necessary extra pressure for starting is obtained from an extension 14 of the coil 21 and is applied at an additional positive electrode 4. A reluctance 23 in the circuit 22 of this electrode automatically renders this circuit inoperative after the lamp is started. The reluctance 23 may be replaced by an electromagnetic switch operated by the coil 7, the primary 11 and secondary 12 being connected from points in the circuit 22 between the electrode 4 and the switch to the lead 8 and the band 6 respectively. In another arrangement, the circuit 22 is connected to the electrodes 4, 5 and receives the extra pressure from a tranformer, the primary of which is connected between the mains 13 in series with the reluctance 23 ; the critical or starting pressure is applied to the band 6 from the extension 14. The auxiliary anode 4 may be dispensed with, as in the arrangement shown in Fig. 4, in which symmetrical extensions 14 of the auto-transformer 21 are connected at starting through switches 19 to the positive electrodes 2, 3. One or other of these extensions supplies the extra pressure, both being then rendered inoperative by moving over the switches 19 to include the resistances 18 in their circuits as shown at the righthand side of Fig. 4. The starting pressure is applied by a reaetance device 17 when the quick-break switch 16 is opened. In another system of connections, one of the mains 13 is connected directly to the lead 9 and through a transformer primary to the cathode 5, the secondary of this transformer supplying the starting pressure to the starting-band. The mains are connected through a transformer, having its secondary placed in the lead 10 and connected to the junction of the second main and the inductance 7. An extension of this secondary supplies the extra pressure to the auxiliary anode 4. Fig. 6 shows an arrangement similar to that described with reference to Fig. 1, but applied specially for converting purposes. The inductance 23 is replaced by a transformer 30 having considerable magnetic leakage between the primary and secondary coils 31, 32. As in practice it is advantageous to give lag or lead to the current applied to the band 6, a transformer secondary 38 is included in the circuit of the band 6, the primary 37 being connected between the mains 13 in series with an inductance or resistance 40 and in shunt to a resistance or inductance 39.