GB627691A - Improvements in and relating to starters for electric discharge devices and circuitstherefor - Google Patents

Abstract

627,691. Control systems for space discharge apparatus. BRITISH THOMSON-HOUSTON CO., Ltd. July 18, 1945, No. 18373. Convention date, July 26, 1944. [Class 38 (iv)] To obtain rapid starting of an electric discharge device, a switch for producing-an inductive " kick " for starting the device is actuated by a piezo-electric crystal. In an arrangement for a pair of similar fluorescent lamps 1, 1, Fig. 1, connected in parallel lead and lag circuits 5, 5 and fed through main switch 7 from a supply auto-transformer 8, a crvstal member 12 of one or two elements is connected in series with filamentary electrodes 2, 2 in each starting circuit 10. A switch 11 has a resilient contact 16 operated by a motion multiplying arm 14 fixed to the " free " end of the crystal. Rapid opening and closing of switch 11 effects substantiallv instantaneous starting of the lamp. A condenser 13 in the " lag " circuit 5, tends to reduce the number of operations of switch 11. A glow discharge device 17, Fig. 2, in the starting circuit 10 may be used to open it after starting. In a modincation Fig. 4, the ballast 6 constitutes the secondary of a transformer having its primary 20 connected through the switch contacts, whereby a starting voltage is produced ; after starting, the winding 20 reduces the voltage in the circuit 10. Specifications 545,935, 559,898 and 569,685, [Group XL], are referred to. The system may be adapted for operation on D.C. by introducing means such as a buzzer for producing rapid intermittent current.