Group 17, Electrical Contactors
17-1-2 • Contactors Specifications and Overhaul SM 765, Nov ’06
CONTACTOR INSPECTION AND
TIP REPLACEMENT
1. Check armature and movable contacts for freedom of
movement by depressing movable arm with a screw-
driver or small rod. Check for any restrictions to
movement and for return of parts by action of spring.
2. Inspect contact tips. Look for any worn or eroded
surfaces. Look for evidence of tip welding.
Inspect for evidence of any contaminants on tips
(paint, dirt, paper or cloth material, etc.) which
would impair operation.
Do not use sandpaper or file tips. Any damage must
be corrected by tip replacement.
Tips must be replaced before they wear through and
damage copper base.
To remove and replace contact tips, use following
3. To replace tips on the contactors, loosen and remove
two cover mounting screws attaching it to coil frame.
(Observe position of positive (+) marking on cover).
Be careful not to lose return spring fitted under cover.
Remove locknut and lockwasher from contact studs
and remove contact studs from top cover. Inspect the
top cover to make sure it has not been overheated and
that the contact studs have not melted into the plastic.
Replace the studs with new.
Lift movable contact assembly off base. Remove
lock ring from armature shaft and remove moving
contact tips. Be careful not to disassemble or lose
other parts under contact tips on armature assembly.
Replace movable contacts with new and assemble
onto armature shaft. Make sure lock ring is fully
seated.
Assemble contactor by putting moving contact
assembly armature shaft into coil plunger with return
spring on top of armature shaft. Put top cover over
spring and install cover mounting screws. Be sure
return spring is in recess in top cover.
N
TE
When assembling top cover to base, make
sure it is installed with positive sign (+) mark-
ings located correctly. Use a bar or rod to
move contacts. Be sure movement is free of
binding and that tips are in correct orienta-
tion and tips contact correct mating parts.
To Next Page
Loading...
