Capacitor welding machine control - for low-loss current setting by pulse sensor and logic multipliers and adders

A capacitor welding machine has a control system for the thyristorised inverter, which governs the capacitor discharge into a welding transformer. The control system includes a sensor for start and end of the welding current pulses. Its output is passed direct, and via a controller for the prim. current pulse interval, and via a sequence switch for the thyristor control, to a logic signal multiplier. Its other inputs come from a controller for the duration of the time intervals of which the welding current pulse consists. Logic adders combine these signals for the thyristor firing units. High welding quality is obtd. because the current pulses have the optimum shape. All metals including heat-resistant and hardening steels can now be welded on the capacitor welding machine. The quality of the weld can be controlled effectively.