Lincoln Electric SAM400 Operator's Manual page 23

D-2
COMMUTATOR AND BRUSH MAINTENANCE
WARNING
Uncovered rotating equipment can be dangerous.
Use care so your hands, hair, clothing or tools do
not catch in the rotating parts. Protect yourself
from particles that may be thrown out by the rotat-
ing armature when stoning the commutator.
The generator brushes are properly adjusted when the
welder is shipped. They require no particular attention.
DO NOT SHIFT THE BRUSHES or adjust the rocker
setting.
Shifting of the brushes may result in:
- Change in machine output
- Commutator Damage
- Excessive brush wear
Periodically inspect the commutator, slip rings and
brushes by removing the covers. DO NOT remove or
replace these covers while the machine is running.
Commutators and slip rings require little attention.
However, if they are black or appear uneven, have
them cleaned by an experienced maintenance man
using fine sandpaper or a commutator stone. Never
use emery cloth or paper for this purpose.
NOTE: If the welder is used in dirty or dusty locations,
or if the welder is not used for prolonged periods of
time, it may be necessary to clean the commutator and
slip rings more often.
Replace brushes when they wear within 1/4" of the pig-
tail. A complete set of replacement brushes should be
kept on hand. Lincoln brushes have a curved face to fit
the commutator. Have an experienced maintenance
man seat these brushes by lightly stoning the commu-
tator as the armature rotates at full speed until contact
is made across the full face of the brushes. After ston-
ing, blow out the dust with low pressure air.
To seat the slip ring brushes, position the brushes in
place. Then slide one end of a piece of fine sandpaper
between slip rings and brushes with the coarse side
against the brushes. With slight additional finger pres-
sure on top of the brushes, pull the sandpaper around
the circumference of the rings, in direction of rotation
only - until brushes seat properly. In addition, stone
slip ring with a fine stone. Brushes must be seated
100%.
MAINTENANCE
Arcing or excessive exciter brush wear indicates a pos-
sible misaligned shaft. Have an authorized Field
Service Shop check and realign the shaft.
COOLING SYSTEM
The SAM welders are equipped with a pressure radia-
tor. Keep the radiator cap tight to prevent loss of
coolant. Clean and flush the cooling system periodi-
cally to prevent clogging the passage and overheating
the engine. When antifreeze is needed, always use the
permanent type.
CONTACTOR MAINTENANCE
Where the output contactor is operated frequently
when tacking or making short welds, turn the engine off
and inspect the contactor every three months:
1. be sure the mating surfaces of silver contacts are
not worn and all make contact at approximately
the same time.
2. Make sure the springs and holders are not broken
or out of adjustment. Approximate spring com-
pression after making contact is 1/8". Less than
1/16" compression indicates worn contacts that
should be replaced.
3. Make sure the moving contact or other moving
parts are not binding.
4. Check interlock contacts and springs. Be sure
mounting screws are tight.
SAM400 & 650
D-2
APR97