WL Circuit Breakers - Siemens

External Power Consumption
WL Circuit Breaker
WL Circuit Breakers with CubicleBUS
are designed to provide internal and
external communication when the
main contacts are open. It is therefore
necessary to connect an external
power supply.
2/33
Table to calculate the power consumption of an CubicleBUS System
CubicleBUS Modules # of CubicleBUS Max. continuous Max. peak inrush
modules per current current for each
breaker module
Trip unit ETU745 1 120mA 2000mA
Trip unit ETU755 1 120mA 2000mA
Trip unit ETU776 1 170mA 2000mA
Metering Function or Metering Function Plus 1 120mA 120mA
Breaker Status Sensor BSS 1 40mA 110mA
COM15/COM16 PROFIBUS/MODBUS communication module 1 125mA 280mA
ZSI module 1 50mA 125mA
Digital output module with rotary switch, relay output 1 - 2 180mA 125mA
Digital output module with rotary switch, opto coupler 1 - 2 50mA 125mA
Digital output module configurable, relay output 1 180mA 125mA
Digital output module configurable, opto coupler 1 50mA 125mA
Analog output module 1 - 2 110mA 800mA
Digital input module 1 - 2 30mA 125mA
BDA or BDA Plus 1
Summary
250mA 350mA
Table
2-23
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 power 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 is sufficient to
not only activate the protective functions of
the ETU745 or ETU748 trip units, but also
to activate the display. However, the backlighting
requires an external power supply.
If the CubicleBUS has been connected to a
UL Listed 24V DC class 2 power supply, the
display is fed with energy from this supply.
To find a suitable external power supply for the WL Circuit Breaker with CubicleBUS the continuous current and the peak inrush current
must be observed.
The display of the ETU776 only functions
when an external CubicleBUS 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 CubicleBUS 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 CubicleBUS consists of four wires, two
for the communications and two for the UL
Listed 24V DC class 2 power supply. The
CubicleBUS is connected to the external
terminal X8.1 to X8.2.
WL PROFIBUS/MODBUS Communication and Electronic Accessories