18
■ Precautions on Wiring of High DC Voltage Start Method
The followng shows a case where the water cooled torch is used.
Never connect the negative (-) side of the weld wire sticking
detection cable to the negative (-) side of the welder output
terminal (at the torch side).
∗ Pay attention to the insulation of the cable at the torch side since high voltage may leak if the
cable directly contacts to the concrete floor, etc.
If the resistance between the electrode and the base metal is 20 MΩ or less when measured
with a 500-V insulation tester, the operation is hard to start. Ensure proper insulation. Pay
attention to the polarity of the measuring device so that the base metal side is always
connected to the positive side.
Note: The occurrence of discharge between the electrode and the base metal confirms the proper
application of high DC voltage (approx. 10 mm, under the argon shielding gas
environment).
Welder
Cooling water circulator:
Use the circulator for high
DC voltage. Insulate from
the floor or other faces by
using an insulation cover
even if the circulator is
provided with rubber legs.
Cooling water path: Insulate
from the other devices since it
becomes the same electrical
potential as that of the electrode
in the torch.
Weld wire
Base metal
Ｐ
Insulation
cover
Insulation resistance:
Requires 20 MΩor
more. (positive side
at base metal)
Cable at base metal:
Be sure to connect to the
positive side output terminal and
ground at the base metal side.
Torch side cable path and torch
fixed section:
Insulate from the other devices.*
Insulation
cover
Weld wire feeder and wire path:
Insulate from the other devices by using an
insulation cover.
High pressure
power supply
Case grounding:
Be sure to ground the case
for safe operations.
- Weld wire
+ sticking detection circuit
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