b. Removal and Installation. Remove and install
when worn under 1 inch or before the limit of
spring travel is reached. New brushes must be
seated before they can be used.
(2) Place new brushes in position with a piece of
58. Brush Holders
medium grade sandpaper under the brush toe
on the commutator.
(3) Hold the brush in its normal position and draw
the sandpaper back and forth under the brush
with the back (smooth side) of the sandpaper
b. Cleaning, Inspection, and Repair.
held closely in contact with the curve of the
(1) Clean all parts in an approved cleaning solvent
commutator. This will sand the brush down to
and dry thoroughly.
the curve of the commutator.
(2) Inspect for cracks, breaks, or other damage.
(4) Blow out all carbon dust from commutator.
Replace damaged or defective parts as
Position brush springs and connect leads as
57. Brush Springs
(2) Install brushes and brush springs (paras 56 and
(1) Check the brush springs to make sure they are
holding brushes on the commutator with a firm,
59. Cleaning Commutator
even pressure. Brush spring tension pressure
Clean commutator with a clean rag or, while running
should be approximately 32 ounces (plus or
with a piece of fine grade sandpaper.
minus 2 ounces).
Important: Never use emery cloth or emery paper
(2) Tension readings are taken with a spring-scale
to clean commutator.
gauge at the instant the brush spring releases
Warning: Care should be exercised in cleaning
contact on the brush. Replace defective or
commutator awhile running to prevent injury to
weak springs as necessary.
Section VII. CONTROLS, INSTRUMENTS, WIRING AND COMPONENTS
b. Removal and Installation.
(1) Remove mounting screws which attach
All controls and instruments necessary for operation of
receptacle and switch mounting plate to front
the Model W300 MG welding machine are mounted on
the front panel with the exception of the remote control
(2) Tag and disconnect electrical lead.
assembly which is a separately contained unit.
(3) Remove attaching hardware and remove switch
61. Receptacle and Switch
(4) Install by reversing above procedure.
a. General. The receptacle and switch (fig. 12) are
used in conjunction with the remote control assembly.
Both are mounted in a common mounting plate and are
a. General. The voltmeter and ammeter (fig. 12) are
removed and installed in a similar manner. If either is
mounted in a common mounting and
found to be damaged or defective it should be replaced.