User Manual

Description
2.3 Protection system
3WA Air Circuit Breakers
68 Equipment Manual, 05/2021, 92310000002-03
2.3.7 Activation limits and power supply
The electronic trip unit does not require auxiliary power. The electronic trip unit is powered
by the circuit breaker’s internal current sensors. Depending on the operational current, the
electronic trip unit of the circuit breaker is activated from:
Size
1 / 2
Size
3
ACT LED (Active) Description
1-pole/2-pole load 80 A 90 A
Flashing
(frequency: 1 Hz)
Electronic trip unit active,
display off
100 A
110 A
On
Electronic trip unit active,
display on
3-pole load 70 A 80 A
Flashing
(frequency: 1 Hz)
Electronic trip unit active,
display off
100 A
110 A
On
Electronic trip unit active,
display on
Alternatively, for a circuit breaker with integrated voltage tap, the ETU600 electronic trip unit
can be supplied via the VTM680 voltage tap module.
If functions with data exchange via CubicleBUS
2
are to be used with the ETU600 electronic
trip unit, an external 24 V DC power supply must be connected to the secondary disconnect
terminals X8-3 and X8-4. This means that the ETU600 is active even when the circuit breaker
is open or when the operational current is below the activation limit.
WARNING
Loss of direct-acting circuit breaker functionality with option code Z = K60
When the circuit breaker is equipped with current sensors without energy cores, the
electronic trip unit is not self-powered.
For these applications, an undervoltage release and an external 24 V DC power supply are
required to power the electronic trip unit.
The auxiliary power supplying the electronic trip unit is internally coupled to the
undervoltage release of the circuit breaker.