Electron beam machining apparatus

The present invention relates to an electron beam apparatus in which a high-voltage power source and an auxiliary power source higher in voltage and greater in internal resistance are connected in parallel with the thus connected member then connected in series to the generating portion of an electron beam device energized by the former high-voltage power source, the former and latter power sources being selectively connected across a change-over switch. The present invention provides an electron beam apparatus which is continuously operated by change-over switching to the high voltage power source, where lesser skilled persons are enabled to operate the apparatus more easily than was the case with the conventional manual method. The auxiliary high voltage power source for conditioning use is capable of obtaining a voltage at least 1.2 times the working voltage of the high voltage power source, and has a large internal resistance. The auxiliary power source connected to a change-over switch allows a voltage more than 1.2 times the maximum working voltage to be impressed upon the generating portion of an electron beam device, effecting the conditioning of the accelerating electrode. After the conditioning, the change-over switch is connected to the former high voltage power source, where the voltage is impressed upon the generating portion of an electron beam device to operate the apparatus. The auxiliary high voltage power source with an output current capacity of only 1 m A is extremely economical, therefore allowing the electron beam apparatus to be manufactured at a reasonable price. (T. Hiroshige)