Tweco 6000 Cutting Systems - Manual (Page 38)

SERVICE 5-8 Manual 0-2689
C. Checking Proper Isolation Resistance
Procedure
The Torch Head and Torch Leads should be tested fur-
ther for insulation breakdown if no other fault has been
found. This procedure requires the use of a Hi-Pot Tester.
WARNING
This procedure should be performed only by a quali-
fied electronic technician.
1. To test the Torch Head center insulator for insula-
tion breakdown use the following procedure:
a. Remove the Torch Head Assembly from the
Torch Leads if not already done.
b. Remove the consumables from the Torch Head
Assembly if not already done.
c. Connect a Hi-Pot Tester capable of producing
2500 VAC between the positive pilot lead and
the negative lead fittings.
d. Increase the output of the Hi-Pot Tester to a
maximum of 2500 VAC.
• If the voltage drops to 0 VAC or leakage
current is detected, then the Torch Head
center insulator is breaking down and the
Torch Head must be replaced.
• If the Torch Head center insulator passes
the test, then proceed to Step 2.
2. To test the Torch Leads for insulation breakdown
use the following procedure:
a. Connect the Hi-Pot Tester between the posi-
tive pilot lead and the negative lead fittings.
The fitting on the other end of the Torch Leads
must be separated (isolated) from each other.
b. Increase the output of the Hi-Pot Tester to a
maximum of 2500 VAC.
• If the voltage drops to 0 VAC or leakage
current is detected, then the insulation be-
tween the Torch Leads is breaking down
and the Torch Leads must be replaced.
• If the Torch Leads passes the test, then pro-
ceed to Step 3.
3. Visually check that the control wires, pilot lead
connection, and negative lead connections are
properly connected and in good condition (no
shorts or arcing).
• If problems are evident, repair or replace as
required.
• If there are no visual problems, then proceed
to Step 4.
4. Check the pilot lead, negative lead and control
wires for opens from one end of the torch leads to
the other.
• If open, replace leads or open component
of the Torch Leads Assembly.
• If not open, then proceed to Step 5.
5. Check the pilot and control wires for shorts to
other components in the Torch Leads.
• If shorted, then replace Torch Leads.
• If not shorted, then proceed to Step 6.
6. Carefully reassemble the components and recheck
the completed assembly per paragraph ‘B’, Step
3 to confirm that the components have been prop-
erly assembled.
This completes the checks for the proper operation of the
Torch Head and Torch Leads.