Tweco Maximizer 300 Torch for BNFL - Manual (Page 37)

Manual 0-2990 5-7 SERVICE
3. Secure the rigid insulator in place with electrical
tape.
4. Connect the plasma, secondary (+), coolant sup-
ply, and coolant return (-) connectors.
5. Secure leads and tubing with single layer of elec-
trical tape.
6. Slide the positioning tube down over the leads
and thread it into the torch adapter on the torch
head assembly.
7. Install the front end torch parts.
5.07 Torch And Leads
Troubleshooting
A. General Information
Failures in the Torch and Leads can be isolated to the Torch
Head or Torch Lead components. To properly isolate the
failed part requires the use of an ohmmeter and a Hi-Pot
Tester.
WARNING
The use of a Hi-Pot Tester should be performed only
by a qualified electronic technician.
In the Torch Head the center insulator separates the nega-
tive and positive charged sections of the torch. If the cen-
ter insulator does not provide adequate resistance, cur-
rent which is intended for the pilot arc may be dissipated
into the torch head, resulting in torch failure.
In the Torch Leads the negative and positive leads are
isolated from each other. If there is not adequate resis-
tance between the leads then torch failure may occur.
B. Quick Check Procedure
This quick check will identify major isolation failures in
the Torch Head or Torch Lead components using an ohm-
meter.
The actual assembly and consumables may vary for dif-
ferent torches but the basic procedure is the same for all
torches. Make the quick check on the Torch Head and
Leads as follows:
WARNINGS
Disconnect primary power to the system before
disassembling the torch or torch leads.
DO NOT touch any internal torch parts while the
AC indicator light of the Power Supply is ON.
1. Remove the consumables from the torch.
2. Disconnect the torch leads from the power sup-
ply to isolate the torch from power supply circuits.
3. Using an ohmmeter (set to 10K or higher), check
for continuity between the positive and negative
torch fittings.
• If there is continuity between the two torch
fittings proceed to Step 4.
• If no continuity (infinite resistance) is found
between the two torch fittings proceed to para-
graph C.
4. Remove the torch head from the leads (refer to
the proper Section on servicing the Torch Com-
ponents).
5. With the torch head disconnected from the leads,
measure the resistance between negative fitting
or cathode body of the torch head and the posi-
tive fitting or anode body of the torch head.
No continuity (infinite resistance) should be mea-
sured between negative and positive sections of
the torch head.
• If there is continuity, torch head must be re-
placed.
• If no continuity (infinite resistance) is found
proceed to Step 6.