Description
2.8 Electronic trip unit ETU
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
46
Manual, 10/2018, L1V30499596002-01
Label for installed internal accessories
You can make a note of the number of installed accessories on the internal accessories
label. Accessories that have been pre-installed in the factory are already listed here.
This tells you which accessories are installed without the need to open the circuit breaker.
You can use this information, for example, to reorder components.
The presence of a metering function can also be seen here by the side of the main contacts
on which the voltage tap is located. (above/below or on the incoming/outgoing side)
Label of circuit breaker data
A label is affixed to the left-hand side of the circuit breaker that provides an overview of the
most important data of the circuit breaker.
Label for guide frame
A label is affixed to the left-hand inside of the guide frame that provides an overview again of
the most important data of the guide frame.
The article number of the guide frame is stated separately on its label even if it is part of the
withdrawable breaker version.
2.8
Electronic trip unit ETU
As a protection device, the circuit breaker has the task of protecting installations and clearing
electrical faults occurring in the system. A trip unit detects whether a fault occurs by
comparing the protection parameters set in it with the measured values. The circuit breaker
has microprocessor-controlled trip units.
The tripping characteristic can be adjusted to the required values with numerous possible
settings.
Selective tripping and instantaneous release
On short-circuits in the medium current range, selective tripping (ST) is ensured. On short-
circuits with a larger current and high arc energy in the arc chute, an instantaneous release
(INST) responds and interrupts the overcurrent immediately (< 30 ms).
One ETU for two versions of the current-limiting (3VA27) and current-carrying (3WL10)
contact system
The kinematic behavior of the two contact systems (ACB/MCCB) of this platform device only
diverges above the maximum settable operating value of the instantaneous short-circuit
release (INST). For this reason, it is possible to use the identical ETU (ETU of the 3-series
and ETU of the 6-series) for both versions.
