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Instructional Leaet IB2C12063H03
Effective March 2012
Instructions for Installation, Operation and
Maintenance of Magnum SB Insulated Case
Low Voltage Power Circuit Breakers
EATON CORPORATION www.eaton.com
Figure 33. Pictorial Diagram of Typical Current Sensing, Processing and Tripping System
The electronic trip units are self-powered. When the circuit
breaker is closed, no external power is required to operate their
protective systems. Current signal levels and the control power
are derived from the current sensors integrally mounted in the
circuit breaker.
A functional local test of a major portion of the trip unit’s
electronic circuitry and the circuit breaker’s mechanical tripping
action can be verified through the trip unit’s test receptacle
(Figure 34). This is accomplished using a Digitrip (DS Type) Test
Kit which provides a secondary injection test that simulates
the current sensors. A small hand held Magnum functional Test
Kit can also be used to check circuitry and mechanical tripping
functions (Figure 35).
When the circuit breaker is shipped from the factory, the trip
unit’s protective functions are normally set at minimum values.
For specific overload tripping characteristics and time/current
curves to coordinate with a load or system, refer to the trip unit
instruction book.
Table 5. Magnum Digitrip Trip Units
Functions 520 520Mm 520MCm 1150m
LSIG Protection Yes Yes Yes Yes
Disable (I) Yes Yes Yes Yes
GF Protection Yes Yes Yes Yes
GF Alarm No Yes Yes Yes
Display No Yesj Yesj Yesk
Programmable No No No Yes
Metering No Yesl Yesl Yes
Power and Energy Values No No No Yes
Power Quality No No No Yes
Communication No No Yes Yes
j One-line, (four characters per line) LCD display.
k Three-line, (eight characters per line) LED display.
l Phase, neutral, ground, and high load current only.
m Available control voltages are 24/48Vdc, 125Vdc, 120Vac and 240Vac
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