TM 9-3431-254-14&P
NOTE: Under normal use, the slip
LUBRICATION
rings will turn a dark brown color.
WELDING GENERATOR - The generator end bear-
ing is the only point on this generator requiring lubrica-
CAUTION: Don't allow any of the
brushes to wear far enough that the
tion. This bearing is packed with enough grease when the
lead imbedded in the brush can rub
unit leaves the factory to last 6 to 8 months under the
most severe use. Greasing twice yearly is sufficient
on the slip rings.
for the bearing under normal use. Pressure fittings are
not recommended because grease, under pressure, may
go through the bearing grease seal and onto the commu-
tator, causing poor commutation and possible damage to
1. Disconnect leads (A) from connectors on brushholder
caps (B).
the commutator.
2. Lift brush (D)) from brushholder (C) for inspection.
Dirt causes more ball bearing failures than any other
If brushes are worn unevenly, or are shorter than 7/16
thing. Dirt may get into the grease when the bearing
inch (11 mm), replace them.
cap is removed for inspection. Therefore, it is not ad-
visable to inspect the bearing more often than about
3. Inspect slip rings whenever brushes are removed for
twice yearly, and then before removing the bearing
servicing brushes or brushholders. Note surface condi-
cap, always wipe it absolutely clean.
tion of rings. Surface should appear smooth and clean.
Remove as much old grease as possible and wash out cap
Scoring or roughness of slip rings may be caused by grit
kerosene, MIL-PD-680. DO NOT
or abrasive substance in brushes, or by oil on the rings
and bearing with
Moderately rough slip rings can be smoothed by holding
use gasoline. Fill the clean bearing cap about 1/3 full of
grade 00 flint paper against their surface while the rings
high quality ball bearing grease. Work as much grease as
are revolving slowly. If the rings are badly scored, the
possible into the bearing. Place cap into position and
unit must be sent to an overhaul facility for repair. After
bolt-tightly. (MIL-L-10924)
cleaning slip rings, blow dirt and grit out of the unit
with compressed air. Do not use over 25 psi (172 kPa)
air pressure to blow dirt out.
4. Slip new brushes into brushholder guides, and piece
caps on top, and screw them into the guides to a "bot-
CAUTION: Do not overlubricate or
tomed" position. The spring attached to the brush will
allow lubricant to become contami-
nated. Do not use ordinary cup grease
determine the pressure at which the brush contacts the
slip rings.
Manufacturer
has available a special ball bearing
5. To fit new brushes to the slip rings, lay a strip of No.
grease (part no. 4141 32) in one-lb. (0.45 kg) containers.
00 sandpaper, smooth side down, on slip ring surface,
and draw sandpaper in the direction of rotation of
ENGINE - Refer to
Engine Manual for
the slip ring, lifting the brush on the return stroke. Con-
specifics on lubrication.
tinue until the brushes have same curvature as the slip
rings. Blow all carbon dust out of the machine using
not over 25 psi (172 kPa) air pressure.
INSPECTION - Every three months (weekly during
heavy usage in dust-laden air) remove the covers from
CAUTION: When removing the lead
the exciter/auxiliary brushes. They are located at the
wires, do so one at a time and replace
control panel end of the generator. If the brushes are
each brush accordingly, to insure that
worn unevenly or are shorter than 7/16 inch (11 mm),
the lead wires are put back onto the
replace all 3 brushes.
proper brushes.