62
Instructions for Installation, Operation and
Maintenance of Magnum SB Insulated Case
Low Voltage Power Circuit Breakers
EATON CORPORATION
www.eaton.com
Instructional Leaflet
IB2C12063H03
Effective March 2012
Alternating “V”
Shaped Plates
Figure 90. Bottom View of Arc Chute
Figure 91. Primary Contacts with Circuit Breaker Open (Not Used
for Contact Wear Inspection)
WARNING
ARC CHUTES MUST ALWAYS BE SECURED PROPERLY IN PLACE
BEFORE A CIRCUIT BREAKER IS INSTALLED IN A CIRCUIT BREAKER
COMPARTMENT. FAILURE TO DO THIS COULD RESULTS IN
EQUIPMENT DAMAGE, BODILY INJURY OR EVEN DEATH.
When the inspections are complete, position each arc chute
down over its respective set of primary contacts, and secure
in place with the screw removed earlier . Torque the arc chute
screws to 35 to 45 in-lb .
Primary Contact Inspection
With the arc chutes removed, visually inspect each primary
contact structure for signs of wear and/or damage . The primary
contacts with the circuit breaker open can be viewed by
looking directly down into the arc chamber (
Figure 91 and 92
) .
A contact wear indicator is provided for each primary contact
and indicates whether or not the contact should be replaced .
Inspection of the contacts using the contact wear indicators is
conducted only with the circuit breaker closed (
Figures 93
) .
Figure 92. Contact Inspection Area with Circuit Breaker Open
NOTICE
WHEN MAKING A CONTACT WEAR INSPECTION, ALWAYS MAKE
THE INSPECTION BY LOOKING STRAIGHT DOWN INTO THE ARC
CHAMBER FOR THE PROPER PERSPECTIVE. VIEWING THE CONTACT
WEAR AREA FROM AN ANGLE COULD DISTORT THE VIEW.
