ESAB Cadd Tig 1500i TA34, Service Manual

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S0740 800 186/E080826/P50
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ch31_15_2
15AP2 Secondary board
The secondary board is fitted on the main transformer 15TM1, diode module 15D1 and
inductor 15L1.
Diode module 15D1 comprises two diodes, rectifier and freewheel diode. During the time
interval between two voltage pulses from transformer 15TM1, the freewheel diode maintain
the welding current from inductor 15L1.
If the diode module has failed, a replacement module must be fitted in accordance with the
instructions on page 44.
Inductor L1 forms an LC circuit with C3//C4 and D1 to reduce the risk of arc extinction at low
welding currents. When rectifier diode 15D1 conducts, the LC circuit charges up. The circuit
is capable of temporarily maintaining a high arc voltage at low current, thus reducing the
risk of arc extinction. Diode D1 prevents capacitor C3//C4 from going negative.
15AP2 Component positions