GB519353A - Improvements in electric welding apparatus - Google Patents

Abstract

519,353. Supply and control systems for resistance welding. ANDRE, H. G. Oct. 15, 1938. Nos. 29875 and 29876. Convention dates, Oct. 16, 1937, and April 8, 1938. [Class 38 (iv)] [Also in Group XXXVII] Switching control. - Welding current is supplied to electrodes 1 by the discharge of dry electrolytic condensers C through the primary winding of a transformer T. the secondary winding of which is connected to the electrodes. The current may be controlled by adjustable means such as an inductance (not shown) regulating the time constant of the condenser circuit. A mercury switch is preferably used to close the discharging circuit manually or otherwise. Several welding equipments may be supplied from the same condenser, mechanically or electrically interlocked switches preventing two equipments from being operated simultaneously. To provide greater charging time several condensers may be charged in parallel from a motor generator E and discharged in turn through the welding transformer by electromagnetically operated mercury switches I energized in sequence by a rotating commutator 21; variable resistances 23 in series with each electromagnet may determine the instant of closure of each switch. A flywheel on the motor generator maintains its speed. A suitable switch, Fig. 5, comprises a sleeve core 15 which is depressed into a mercury pool 17 when a winding 14 is energized to cause contact between the pool 17 and mercury in an insulating vessel 18.