Eaton QD5 Manual page 15

Contact erosion patterns
MOVEABLE
ARCING
CONTACT
Contact erosion is a function of many variables such as tap voltage load current and
power factor reactor design and tapped winding design. MEPS employs both equalizer
and conventional windings which will produce the typical erosion patterns above.
Figure 16. Contact life stages.
Copper
ARCING
INSERT
STATIONARY
CONTACT
EROSION
INTERMEDIATE STAGE
EROSION HAS PROGRESSED TO A POINT WHERE
MINIMUM OF ORIGINAL
CONTACT SURFACE REMAINS
EQUALIZER
WINDING PATTERN
END OF CONTACT LIFE STAGE
QD5 QUIK-DRIVE TAP-CHANGER INSTALLATION AND MAINTENANCE INSTRUCTIONS MN225012EN March 2016
MOVEABLE
ARCING
CONTACT
NEW CONTACTS
NEW CONTACTS
BURNING CAN OCCUR ON COPPER
CONVENTIONAL
WINDING PATTERN
Copper
ARCING
INSERT
STATIONARY
CONTACT
EROSION
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