Stationary
Arcing
Contacts
Insulating Link
Moving Main
Contact
Assembly
Stationary
Main
Contacts
Arcing Contact
Spring
Figure 3-6 Type DSII-516 Pole Unit Assembly (Front View)
To remove a barrier, carefully but firmly grasp the top of the
barrier and pull upward until it clears the circuit breaker chas-
sis. Note all cautions and instructions printed directly on the
barriers during removal or replacement. These notes help to
insure proper positioning of the barriers in the circuit breaker.
In addition, the barriers are designed such that proper seat-
ing of the barriers cannot be accomplished, if the barriers are
not replaced correctly.
3-6 DE-ION Arc Chutes (Interrupter Assemblies)
The arc chutes mount on top of the pole units, well down
over the arcing contacts (Figure 3-1). This positioning con-
fines arcs inside the chutes at all times and for all values of
current.
Each arc chute contains crosswise, vertical steel splitter
plates having an inverted “V” notch to attract the arc and
interrupt it, by essentially cooling and stretching the arc. In
addition to steel plates, the larger arc chutes include hard,
arc-resistant glass polyester plates. These plates produce
turbulence in the exhaust gases above the steel plates, and
Moving Arcing
Contacts
Molded
Base
Moving
Main
Contact
Upper
Terminal
Lower
Terminal
Figure 3-7 Type DSII-516 Pole Unit Assembly (Rear View)
prevent electrical breakdown over the top of the arc chute or
to ground. The arc chute components are all assembled in an
insulating jacket.
CAUTION
NO ATTEMPT TO REMOVE THE ARC CHUTES SHOULD BE MADE
UNTIL STORED ENERGY SPRINGS ARE COMPLETELY DIS-
CHARGED.
Each arc chute is held in position by one top inserted screw.
To remove an arc chute, remove the mounting screw and lift
the arc chute out of the circuit breaker (Figure 3-9).
3-7 Electronic Tripping System
The electronic trip unit can be considered the intelligence
part of what is a three part, flux transfer tripping system.
The integrally mounted sensors and the trip actuator make
up the rest of the system (Figure 3-10). All three parts of the
system are discussed here. For more detailed information
about the specific trip unit used with Types DSII and DSLII
Effective July 2010
Instructional Book
IB694C694-03
20
eaton corporation
www.eaton.com
