Edition 050614
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cu20d_20_2
20AP2:6 TIG Gas valve
Gas valve 10YV1 is controlled by the processor on circuit board 20AP1. It can
be activated via service function no. 10.
20AP2:7 TIG HF starting device
The 10AP1 HF starting device is controlled by the processor on circuit board
20AP1. It is activated during the starting sequence until the arc strikes, or for a
maximum of 0.7 seconds. The voltage on the primary side of transformer
10TV1 is about 500 V, producing a secondary voltage of 10 -- 12 kV, if a 4
metre long welding torch is connected. If the welding torch is 16 metre the HF
spark is about 8 kV.
Due to electromagnetic interference regulations the energy in the HF ignition
spark is limited. The HF spark weakens with increasing length of the torch. The
HF ignition is satisfactory for welding torches up to 16 metres.
20AP2:8 TIG Starting
The welding torch trigger switch is supplied at 4 2 V AC. Closing the contact
activates IC1 and supplies a Low signal to 20AP1.
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