Current source for electron beam melting or welding system - has controllable rectifier and medium frequency chopper between mains and HV transformer

摘要

The current supply circuit is intended for an electron beam melting or welding system. The required direct voltage is obtained from alternating current mains via a high voltage transformer with a rectifier on its secondary side. Between the mains (RST) and the transformer (4) is incorporated a controllable semiconductor rectifier (1) and a mean frequency chopper circuit (3). Pref. the middle tap (43) of the transformer primary (41) is connected to one pole (12) of the rectifier. The two primary ends (44, 45) are connected to the rectifier other pole (11) alternately via thyristors (32, 31) and diodes (33, 34) in anti-parallel to the thyristors. Capacitors (5) are in parallel to the transformer windings.