Communication-capable Circuit Breakers
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WL Circuit Breaker
External power consumption of a WL Circuit Breaker with
Cubicle
BUS
WL Circuit Breakers with
Cubicle
BUS
are designed to
provide internal and external
communication when the main
contacts are open. It is therefore
necessary to connect an
external power supply.
General information
The current sensing devices of WL
Circuit Breakers consist of two
components. The Rogowski coils
deliver the current measuring
values, and the energy converters
provide the trip units with power.
For breakers without an additional
external supply, the trip units are
already activated and monitor the
current at minimum values of 80A
for Frame Size II, and 150A for
Frame Size III.
The current from the sensors are
sufficient to not only activate the
protective functions of the ETU745
or ETU748 trip units, but also to
activate the display, however, the
back-lighting requires an external
power supply. If the
Cubicle
BUS
has
been connected to a UL Listed 24V
DC class 2 power supply, the display
is fed with energy from this supply.
The display of the ETU776 only
functions when an external
Cubicle
BUS
power supply has been
connected. The protective functions
are fully operational when primary
current is flowing even though the
display is not active.
If additional
Cubicle
BUS
components
are applied on a WL Circuit Breaker,
the breaker must be connected to
an external UL Listed 24V DC class
2 power supply.
The
Cubicle
BUS
consists of four
wires, two for the communications
and two for the UL Listed 24V DC
class 2 power supply. The
Cubicle
BUS
is connected to the
external terminal X8.1 to X8.4.
Table 2-23
To find a suitable external power supply for the WL Circuit Breaker with
Cubicle
BUS
the continuous current and the peak inrush current
must be observed.
WL PROFIBUS Communication and Electronic Accessories • July 2004
