GB693229A - Improvements in or relating to means for catching fish by electricity - Google Patents

Abstract

693,229. Condenser arrangements. SIEMENS - SCHUCKERTWERKE AKT. - GES. Aug. 10, 1950 [Aug. 10, 1949; Sept. 3, 1949; Feb. 18, 1950; March 8, 1950; March 28, 1950; March 28, 1950], No. 19965/50. Class 38 (iv). [Also in Groups VI and XL (c)] In an arrangement for catching fish by means of D.C. impulses transmitted through the water between electrodes 5, 6, a condenser 1 is connected through a choke 4 to a D.C. charging source 12 and a mechanical high-speed switch 15 or an ignitron connects the condenser to the electrodes when the voltage on the condenser is a maximum above the D.C. charging voltage and disconnects the condenser from the electrodes when the discharge current passes through zero. The mechanical switch 15 is closed by utilizing the momentary voltage developed on a winding 19 on a switch coil 18 in the charging circuit when the oscillatory charging current passes through zero and the . opening of the switch is effected by utilizing the voltage on a winding on a second switch coil 17 in the discharge circuit when the oscillatory discharge current passes through zero. The second switch coil 17 delays both the rise and fall of the discharge current and prevents arcing at the switch contacts. A dry rectifier may be substituted for or inserted in series with the second switch coil 17 and the reverse voltage developed on the rectifier when the discharge current passes through zero may be used to open the switch. The switch may be actuated by cam-controlled means or by electric timing circuits. Each switch coil 17, 18 consists of a single conductor around which a thin ribbon of nickel-iron alloy is wound and each is saturated by the current passing through it except when the current is nearly zero. The magnetic characteristic of the switch coils is rectangular. When an ignitron is used instead of the mechanical switch it is ignited by utilizing the reversal of voltage on a resistance inserted into the charging circuit or by utilizing the voltage developed on a resistance connected by a rectifier to a resistance in the charging circuit. When the D.C. charging source consists of an A.C. generator and a rectifier the reverse voltage developed on the rectifier by the oscillatory charging current may be utilized to ignite the ignitron. In order to vary the voltage, duration and frequency of the discharge impulses the choke 4 and the condenser 1 are sub-divided into groups of elements which can be connected in series and/or parallel and the D.C. supply voltage is varied by means of a regulating resistance in the shunt winding of the D.C. generator. The current impulses may be arranged in groups separated by relatively long intervals without any impulse.