GB614749A - Improvements in or relating to devices for generating impulse voltages - Google Patents

Abstract

614,749. Testing impulse voltage. PHILIPS LAMPS, Ltd. July 24, 1946, No. 22006. Convention date, Oct. 20, 1942. [Class 37] In an impulse generator comprising a condenser charged from a D.C. supply and discharged through the test specimen, the specimen is connected in series with a gas discharge tube having liquid main electrodes and an ignition electrode serving as a control electrode. As shown, the impulse voltage condenser 1 is charged from the source 4 through the switch 3 and resistor 2. The discharge path consists of the gas-discharge device 5, resistor 8 and specimen 9, and the device 5 has mercury pool electrodes 6, 7. Series-connected resistor 15 and condenser 16 are in parallel with condenser 1, and the spark-gap 17 is connected across condenser 16 in series with the resistor 19 and potentiometer 20. The tapping of potentiometer 20 is joined by lead 22 to the ignition electrode 21 constituted by a quartz tube partially immersed in mercury pool 7. The horizontal and vertical plates of the oscilloscope 12 are connected to the high potential ends of resistor 19 and the specimen respectively. Upon closure of switch 3, the condensers 1 and 16 charge, and when the breakdown voltage of the gap 17 is reached by condenser 16, the gap conducts, an impulse voltage is applied to ignition electrode 21 through tapping 20, the device 5 becomes conducting and condenser 1 discharges through specimen 9. The time lag between the commencement of the time-base voltage as the oscilloscope horizontal plate and the initiation of the impulse through 9 is controlled by the potentiometer tapping 20. Displacement of the tapping to left or right respectively reduces or increases the lag.