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Instruction Booklet
IB 52-01-TE
Effective October 2010
Instructions for the Eaton Type CM52
Network Protectors 800 to 4500 Amperes
EATON COrPOrATION www.eaton.com
7 IB -52-01-TE
Effective 11/05/08 (super cedes 11/19/03) IB 52-01-TE
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construction provides high strength structural
properties, excellent dielectric ch aracteristics and
resistance to arc tracking. The 3-piece
construction app roach provides suppo rt while
isolating and insulating power conductors.
1. A
2-Piece
engin eered
thermoset
composite resin case enclosed current
path and arc chamb ers. The chambers
act to chann el arc gas es up and out o f
the circuit breaker during interruption.
2. The operating mechanism sits on the
front of the case and is electrically
isolated from cu rrent contact structures.
An insulating dead front cov er cov ers
the completed break er.
4.3 POLE UNIT
A current carrying pole unit is individually
enclosed and rigidly supported by the cas e. The
individual chambers provide fo r pole unit
isolation and insulation from on e anoth er. Each
pole unit has one p rimary contact assembly,
which consists of a moving portion.
4.3.1
Primary Moving Contacts
Depending upon the fram e size, each p rimary
moving contact assembly is comprised o f
multiple individual copper contact fing ers
connect ed to the load conductor through flexible
braided conn ectors. Two fl exible connectors are
used to connect each finger to the load
conductor. The number o f fingers used d epends
upon the circuit breaker’s continuous and short-
circuit current ratings.
The middle four contact fingers perfo rm both the
main and arcing contact functions o f the moving
contacts. A highly conductive alloy pad is part
of the cont act finger and functions as the moving
main contact, and is called the “ Heel”.
A contact wear indictor is provided for each
contact assembly. When making a contact wear
inspection, always look straight down into the
arc chamber to eliminate parallax. The contact
wear indicator is a side-to-sid e ledge, whi ch is a
part o f the arc chamber. With the contacts
closed and in good condition, the ledge is
covered by the back edge of the moving contacts.
If the back edge o f the moving contacts does not
totally cover this l edge, the contacts should be
replaced
Fig.11a
Main Contacts Open
Fig. 11b
Main Contacts Closed
