Lincoln Electric Classic 300 MP Service Manual page 50

LINCOLN ELECTRIC
Cleaning slip rings
7. In the event that the slip rings have become dirty, discolored or mildly pitted, it will be necessary to
clean them, using very fine emery cloth.
Seating brushes
8. If brushes have been replaced, repositioned or are not making full contact with the slip rings, it will
be necessary to re-seat them. This can be done by placing a strip of 180 grit sandpaper between the
slip rings and the brushes, with the abrasive side against the brushes. Pull the sandpaper strip
around the circumference of the slip rings in the direction of rotor rotation only. Repeat this
procedure until the surface of each brush is in full contact with its matching slip ring.
9. Using low pressure compressed air to thoroughly blow the carbon, commutator stone and
sandpaper dust from the machine before operating.
10. Securely connect the leads to the brush terminals. See Wiring Diagram.
11. Using a 5/16" nutdriver, attach the four screws securing the exciter cover to the machine.
Figure F.19 – Exciter cover locations
Classic® 300 MP Service Manual
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