Quick Guide to Replacing DC Contactor, Arc Chutes and Coils
All poles with blowout coils also have arc chutes. To remove the arc chute, loosen the captive screw “A” and slide the arc chute off in the horizontal direction. With the size 4 and 5 contactors, it is also necessary to release the arc chute latch “B”. This may be effectively done with a screw driver used to release the latch and slide the arc chute in the same motion.
In normal service, the arc chute is good for the life of the contactor and requires no maintenance. Operation beyond rating may cause excessive erosion of plastic or ceramic. Replacement is necessary only if there is evidence of ceramic or plastic walls wearing through, or if there is extreme ceramic melting caused by an overload.
Replace the arc chute by sliding it over the arc runner and between the pole pieces. Tighten captive screw “A” and ensure that latch “B” is engaged. There must be electrical contact at arc chute support “C”, figure 4.
To replace coils, remove the arc chutes, remove the two screws supporting the lower terminal block, and unhook the armature tension spring. Do not loosen or otherwise change the adjustments of the armature tension spring because this is factory adjusted for proper pick up.
Remove the armature assembly and the C-ring retaining the coil. Remove the coil. Replace the coil and reassemble in reverse order. Spring washer clips and locking screws are used on some contactors to prevent coil shifting. Reassemble and adjust if necessary to hold the coils firmly in place.