Eaton Magnum SB Series - Electronic Tripping System; Microprocessor-based Trip Unit

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Instructions for Installation, Operation and
Maintenance of Magnum SB Insulated Case
Low Voltage Power Circuit Breakers
EATON CORPORATION www.eaton.com
Instructional Leaet IB2C12063H03
Effective March 2012
Electronic Tripping System
The Magnum SB circuit breaker utilizes a three part tripping
system (Figure 33):
• Microprocessor-based trip unit
• Current Sensors
• Trip Actuator
All three parts of the tripping system are discussed here,
except that the trip unit itself is not discussed in detail. For
detailed information pertaining to the different trip unit models
available with Magnum SB circuit breakers, refer to the specific
instruction leaflet dedicated to the trip units (IL70C1036 and
IL70C1037).
Microprocessor-Based Trip Unit
Magnum circuit breakers use any one of a family of Digitrip
RMS trip units whose main features are summarized in Table 5.
Model 520 is plug compatible and interchangeable in the field.
Figure 30. Cross Section of Conductor and Arc Control System
Top
“V” Shaped
Plates
Top Plate for
Arcing Contact
“V” Shaped
Plates
Figure 31. Magnum Arc Plate Assembly
Integral Arc
Runner
Figure 32. Integral Arc Runner Viewed From Top of Arc Chamber
(Arc Chute Removed, Circuit Breaker Closed)