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17
HF ARC-OVER ON THE SHROUDED SOCKET OUTLET
When the unit is started in DC or AC mode with HF by pressing the Torch button without holding
the tungsten electrode close to a workpiece, check whether the condition of the insulation on the
shrouded socket outlet and on the Torch button connection. The insulation should be undamaged.
If the insulation is damaged, you will hear high voltage arc-overs at certain points.
Possible causes:
•
Mechanical damage to insulation.
•
O-ring on torch defective.
•
Connection of shrouded socket outlet in unit not gas-tight.
A gas leak will facilitate HF arc-overs to the enclosure.
18
NO HIGH-VOLTAGE STARTING PULSES (HF)
Possible causes:
•
Poor insulation or poor gas-tightness on the shrouded socket outlet.
•
Starter A7 not supplied with 42 V AC (check at 42 V AC).
•
42 V AC not applied between trigger inputs T0 and T70.
•
Starter A7 defective.
When welding with AC, and if the HF is inadequately stabilised, change-over of the trigger inputs
to output voltage (after starting an arc) will not function properly (see section A6-2).
Possible causes:
•
Cable harness of module A6: 20-way ribbon cable connection from control unit A2 to control
A6.
Improvised starter test
1.
Disconnect starter outputs DB and D0, and insulate cable connections.
2.
Connect two bare wires and bend them together to obtain about 2 mm spacing.
3.
Start the unit in HF mode: HF must arc over between the wire ends.
The starter is defective if there are no HF pulses generated when supply and trigger voltage are
applied.
19
NO GAS
Possible causes:
•
Gas cylinder
•
Pressure reducer
•
Gas valve connections not supplied with 42 V AC
•
Gas valve defective
•
Gas connection on the torch
•
Torch
•
Defect on control unit A2
•
Defect on control unit A6
The signal used to control the gas valve Y01 is generated on control unit A2 and goes via the sup-
ply and control bus to module A6 where it controls a relay that connects 42 V AC to the gas valve
Y01.
Summary of Contents for Aristotig 405 AC/DC
Page 1: ...0458 165 002 9910 DTG 405 Aristotig 405 AC DC Welding rectifier Service manual...
Page 9: ...9 NOTES...
Page 10: ...10 CONNECTION DIAGRAM DTG 405...
Page 11: ...11...
Page 15: ...15 NOTES...
Page 16: ...16 BLOCK DIAGRAM DTG 405 405a pcx...
Page 17: ...17 Warning Some parts of this circuit are connected to mains voltage potential 405b pcx...
Page 27: ...27 A2 COMPONENT POSITIONS a2 1b pcx a2 2b pcx...
Page 40: ...40 A9 A13 COMPONENT POSITIONS A10 A14 COMPONENT POSITIONS...
Page 62: ...62 8 WAVEFORM AC2 SMOOTH WAVE ac2 pcx...
Page 81: ...81 NOTES...
Page 91: ...page...