HH187 sparking

[TR3A]

It's my understanding that when I touch the wire to the workpiece, it should be cold. Until I pull the trigger on the gun...there should be no spark at all. On mine, I sometimes do get a small spark, though just very briefly. Most times, I get nothing. Is this normal? Thanks.

[84ZMike]

It's normal....it's the cap. discharging

[TR3A]

Good to know. Thanks!!

[jsee238]

84Zmike is prolly correct. Weld a small bead and touch the wire to the work piece it will prolly do as you say it is doing but it should not do it a second time, because the cap has already discharged its remaining voltage. If it does spark a second time the trigger contact may be sticking.

[Hobart Expert Darrell]

It's my understanding that when I touch the wire to the workpiece, it should be cold. Until I pull the trigger on the gun...there should be no spark at all. On mine, I sometimes do get a small spark, though just very briefly. Most times, I get nothing. Is this normal? Thanks.

There is a bleed resistor across the output capacitor to discharge it after the gun trigger has been released. The discharge takes approximately 2 seconds. A capacitor discharge is an exponential function, so the output voltage drops very quickly immediately and then slows down a little as the voltage gets very low. If you touch the wire to the weldment immediately after the trigger has been released, you may see a spark; depending upon the state of discharge through the bleed resistor.

Darrell