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I.L. 70C1037H02
Figure 1.5 Wiring Diagram for 520M Models and Ground
Alarm/Power Supply Module
1.7 Display Feature (520M family only)
The Digitrip 520M and 520M
i
models have a user inter-
face in addition to the green and red LED trip indicators.
This seven element display performs a metering function
and can be used to monitor load currents.
When the Step button on the face of the trip unit is
pressed and released, the display will show PH 1, for
Phase 1 or A, and the current value. If the Step button is
not pressed again, the display will continue to show the
current value for Phase 1. Each time that the Step button
is pressed, the next monitored function will be displayed.
The other readings can be displayed in the sequence
below:
PH 2
Phase 2 (B)
PH 3
Phase 3 (C)
PH 4
Neutral
PH 5
Ground (if Ground function is supplied)
HI
Highest phase current
OL
Overload (Digitrip in overload mode)
Pushing the Step button while the unit is in the OL
mode will have the unit again display the overload
current value.
HELP
This message can indicate more than one prob-
lem with the trip unit. If the rating plug is missing,
a HELP message and an Instantaneous trip LED
light will be observed. The rating plug needs to be
installed and the Instantaneous trip LED must be
cleared by pressing the Reset/Battery Test button.
This message could also indicate that the trip unit
is out of calibration and should be replaced at the
earliest opportunity.
1.8 Standards
The Digitrip 220, 520, and 520M Trip Units are listed by
the Underwriters Laboratories, Inc.
,
under UL File
E52096, for use in Magnum Circuit Breakers. These same
units are also listed by the Canadian Standards Associa-
tion (CSA) under file LR 43556.
All Digitrip units have also passed the IEC 947-2 test
program which includes radiated and conducted emission
testing. As a result, all units carry the CE mark.
2.0 GENERAL DESCRIPTION OF MAGNUM CIRCUIT BREAKERS
2.1 General
Magnum Circuit Breakers are tripped automatically on
overload fault current conditions by the combined action of
three components:
1. The Sensors, which measure the current level
2. The Digitrip Trip Unit, which provides a tripping signal
to the Trip Actuator when current and time delay
settings are exceeded
3. The low-energy Trip Actuator, which actually trips the
circuit breaker
Figure 2.1 shows this tripping circuit for a typical Magnum
Breaker. This arrangement provides a very flexible
system, covering a wide range of tripping characteristics
described by the time-current curves referenced in Section
9.2.
The automatic overload and short circuit tripping charac-
teristics for a specific circuit breaker are determined by
the ratings of the installed current sensors with a matching
rating plug and the selected functional protection settings.
Specific setting instructions are provided in Section 4.
