Overcurrent protector of direct current arc welding machine

Abstract

Abstract PURPOSE: To protect the DC power supply against abnormal states by providing an arc voltage detecting element, a time constant circuit consisting of a resistance and capacitor, a driving element, a control element, etc. to the captioned protector. CONSTITUTION: In the captioned overcurrent protector, the charging voltage Vc of a capacitor C changes and the operation level of the 2nd transistor Tr 2 is beforehand determined and the time reaching for this becomes faster as the voltage Vp is higher and longer as it is lower. The voltage Vp contributing to the charging of the capacitor C is taken from the output of an amplifier IC and the voltage at the point P starts charging to the capacitor C as the 1st transistor Tr 1 goes OFF when the output voltage becomes set voltage or less. This charging voltage is converted to the voltages Vpw, Vpt by the voltages Vsw and Vst at the wire shorting. Because of Vsw > Vst, they become Vpw < Vpt and the voltage Vc of the capacitor C reaches the operation level of the transistor Trp. In the case of the voltage Vst, the gate block circuit operation time becomes faster than the operation time of the case of the voltage Vpt, thus safe current is supplied. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Hideo Ishii
• 👤 Haruo Moriguchi
• 👤 Hirobumi Yoshikawa
• 👤 Masao Katooka
• 👤 Kunio Kano

Bibliographic Details