| 摘要 |
ARC WELDER WITH IMPROVED ARC STRIKING CAPABILITY A pulse type arc welder with improved arc starting characteristics. An output voltage level sensor (2017) monitors the output voltage to determine whether the arc has been struck. If the arc has not been struck, a first oscillator (2000) gates a second, higher frequency oscillator (2002) so that the input to the driver (2010) is a chopped, pulsed, high duty cycle waveform. Also, the bandwidth of the output current level sensor (2012) is reduced so that the high value, short lived arc starting transient current does not cause the output current level sensor (2012) to improperly shut down the driver (2010). Additional current limiting protection is provided during this period since the high chopping frequency causes the reactor (2010a) to have a high impedance. After the arc has been struck, the output voltage will drop to the arc sustaining voltage and the output voltage level sensor (2017) will de-energize relay (2003). The first oscillator (2000) then provides the driver (2010) with an input signal having the characteristics selected for the particular welding operation. Also, the bandwidth of the output current level sensor (2012) is restored to its full value.
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