Troubleshooting and repair – Lincoln Electric CLASSIC SVM194-A Manuel d'utilisation
Page 174
WELD CIRCUIT GROUND AND SHORT CIRCUIT TEST PROCEDURE
(continued)
PROCEDURE
1. Turn the engine off.
Weld circuit ground test:
2. Measure the resistance between either of the
two weld output terminals and a clean chassis
ground connection.
The resistance measurement should be very
high 500,000 (500k) Ohms minimum.
If the resistance is lower than 500k Ohms:
3. Remove the welding generator brushes, or pull
them away from the commutator and isolate
them so they cannot come in contact with any-
thing except the brush holder they are attached
to. Remove the jumper plug or wire feed mod-
ule harness from Plug J5. See wiring diagram.
4. Check the resistance between chassis ground
and each output terminal, and between chassis
ground and the commutator.
If the commutator has low resistance to chassis
ground, the armature will need to be replaced.
5. If the resistance measured at the "POSITIVE"
weld terminal is low, carefully examine the inter-
pole coils, and the heavy leads, and the brush
holders connected to the interpole coils. Check
for damaged, dirty or missing brush holder insu-
lators. Check for a damaged or dirty weld out-
put terminal. Check the yellow lead connecting
the brush holder to Plug J5.
6. If the resistance measured at the "NEGATIVE"
terminal is low, examine the range selector
switch, the series coils, and the heavy leads
and brush holders connected to them. Check
for damaged, dirty or missing brush holder insu-
lators. Check for a damaged or dirty weld out-
put terminal. Check the white lead connecting
the flashing diode to Plug J5.
7. Test for a short circuit condition between
the electrode and work circuits.
8. With the brushes still isolated as described
above, check the resistance between the two
weld terminals. The resistance should be very
high, 500,000 (500k) Ohms minimum.
9. If the resistance measurement is too low, check
the heavy weld current carrying leads and con-
nections for damaged insulation or dirt buildup
between the negative (Series Coils) and posi-
tive (Interpole Coils) circuits. If the low resis-
tance point is between the stator coils, the coils
will require replacement or repair. Check for
insulation damage between the yellow and
white leads connecting to J5.
TROUBLESHOOTING AND REPAIR
F-52
F-52
CLASSIC® 300D & 300G