end wrappers, removal and installation.
(1) Place a commutator-wide strip of No.00
4-39. Dynamotor-Welder Brush
Replacement
sand paper (under the brush, abrasive side out-
a. Replacement..Replace and adjust brushes as
ward.
CAUTION
b. Cleaning and Inspection,
Do not use emery cloth when seating
(1) Clean brushes with a clean, dry, lint-free
cloth .
brushes as this will short circuit the
(2) Inspect for cracks, chips, and excessive
commutator.
wear. Replace brushes that are worn to less than 3/4
(2) With the brush in place, press down on the
inch.
brush and draw the sand paper back and forth until
c. Installation. Install the brushes and adjust
the brush has the same contour as the commutator.
Repeat for each brush.
d. Seating Brushes. All brushes must be properly
(3) Test the brush seat by operating the
seated on the rotating surfaces to insure maximum
dynamotor-welder for a few minutes, stopping it.
operating efficiency of the dynamotor-welder. The
and examining the brush seat. The seat area should
following contouring procedure applies to all
show at least 80 percent highly polished by contact
dynamotor-welder brushes:
with the rotating surface.