Siemens SENTRON VL Series System Manual page 25

Sizes and versions
● With three sizes, the 3WL air circuit breaker covers the range from 250 A to 6300 A.
● The 3WL is available in a three-pole and four-pole version
● There is a fixed-mounted 3WL circuit breaker version, and a withdrawable version.
● The devices are available in different switching capacity classes, so short-circuit currents
up to 150 kA can be safely shut down.
Adaptation
The 3WL air circuit breaker can be adapted to prevailing plant conditions. Each circuit
breaker can be set to the suitable rated current, for example, using a rated current module.
This ensures optimal protection characteristics even when the plant is modified. The module
can be replaced quickly. Time-consuming replacement of the transformer is not necessary.
Parameter set switchover (ETU76B)
It is possible to switch between two different parameter sets. This function is necessary, for
example, if an automatic change is made from mains operation to generator operation in the
event of a power failure and there is the possibility of all tripping conditions changing.
Safety
It is possible to prevent undesired switching on by means of interlocks and locking options
on the switch.
Example
The accessories, from the auxiliary release, motorized operating mechanism all the way to
the communication system, are simple and easy to retrofit. The accessories are the same
across the entire range. This simplifies ordering and reduces stockkeeping costs.
Solid-state overcurrent trip unit (ETU)
The core of each switch is the solid-state overcurrent trip unit (ETU). There are three
different options for adapting the protection functions, metering functions, and signaling
functions to the requirements of the plant: From simple overload protection and short-circuit
protection, up to trip units with a host of metering and signaling functions that can be
parameterized remotely.
Communications capability
All circuit breakers with trip units of the type ETU45B and ETU76B have communications
capability. Additional components that are networked internally via the CubicleBUS can be
installed in these communication-capable trip units. To confer communications capability on
a 3WL with the ETU15B, ETU25B or ETU27B trip unit, the overcurrent release must be
replaced as this trip unit has no facility for connecting to the CubicleBUS.
3WL/3VL circuit breakers with communication capability - PROFIBUS
System Manual, 03/2011, A5E01051353-02
3WL air circuit breakers
3.1 Introduction and overview
25