Lincoln Electric Classic 300 MP Service Manual page 69

LINCOLN ELECTRIC
8. Test for a short circuit condition between the positive and negative circuits.
9. With the brushes still isolated as described above, check the resistance between the two of the
weld terminals. The resistance should be very high, 500,000 (500k) Ohms minimum.
10. If the resistance measurement is too low, check the heavy weld current carrying leads and
connections for damaged insulation or dirt buildup between the negative series coils circuits. If the
low resistance point is between the stator coils, the coils will require replacement or repair.
Figure F.30 – Weld output terminal location
Classic® 300 MP Service Manual
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