Instruction Book
Page 63
Effective: May 2006
I.B. 2C12060H08
For more information visit: www.EatonElectrical.com
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.
The contact wear indicator is the relative position of the
individual contact fingers to a narrow, side-to-side ledge
inside the arc chamber. The ledge is actually part of the
arc chamber. When the circuit breaker is closed and
the contacts are in good condition, the narrow ledge is
covered by the back end of the contacts (Figure 6-5). If
the back end of the contacts do not totally cover the
ledge, the contacts should be replaced.
ARC CHUTES MUST ALWAYS BE SECURED PROP-
ERLY IN PLACE BEFORE A CIRCUIT BREAKER IS
INSTALLED IN A CIRCUIT BREAKER COMPART-
MENT. FAILURE TO DO THIS COULD RESULTS IN
EQUIPMENT DAMAGE, BODILY INJURY OR EVEN
DEATH.
Once the inspection is complete, be sure the arc chutes
are properly replaced as previously described in para-
graph 6-4.1.
WARNING
ARC CHUTES MUST ALWAYS BE SECURED PROP-
ERLY IN PLACE BEFORE A CIRCUIT BREAKER IS
INSTALLED IN A CIRCUIT BREAKER COMPART-
MENT. 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.
6-4.3 PRIMARY CONTACT INSPECTION
With the arc chutes removed, visually inspect each pri-
mary 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 6-3 and 6-4).
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 con-
tact wear indicators is conducted only with the circuit
breaker closed (Figures 6-5).
Figure 6-4 Contact Inspection Area with Circuit Breaker
Open
Arcing
Contact
(Toe)
Stationary
Main Contact
(Side View)
Moving Main
Contact
Integral
Arc
Runner
Figure 6-3 Primary Contacts with Circuit Breaker Open
(Not Used for Contact Wear Inspection)
NOTICE
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