Siemens UL1066, UL 489 specifications General information

Models: UL 489 UL1066

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Communication-capable Circuit Breakers

WL Circuit Breaker

External power consumption of a WL Circuit Breaker with CubicleBUS

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.

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 CubicleBUS 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 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 X8.4.

Table 2-23To find a suitable external power supply for the WL Circuit Breaker with CubicleBUS the continuous current and the peak inrush current must be observed.

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WL MODBUS Communication and Electronic Accessories • January 2005

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Siemens UL1066, UL 489 specifications General information