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9.3 External voltage supply
The basic protective functions (L, S, I, & G) of the electronic trip units do not require an auxiliary power supply.
To use the extended functions of trip units ETU745 - 776 requiring data exchange via the c, an external 24 V DC (class 2) voltage
supply must be connected.
Connection
Version A: Connection to hand plug X8 (preferred version)
Version B: Connection to any cmodule
Requirements
The external voltage supply with 24 V DC must fulfill at least the requirements of UL class 2.
To supply power to a circuit breaker equipped with the maximum possible number of external cmodules, one of the Siemens
power supply units listed below can be used. If a second circuit breaker is to be supplied, a second power supply unit is also required.
The external power supply used for electronic components must not be used to supply the motor-operated mechanism.
When using voltage supply units from other manufacturers, the following conditions must be fulfilled:
- Primary-switched-mode power supply unit
-24 V DC, ± 3 %
- Current rating: 2.5 A per circuit breaker maximum possible number of external cmodules or 3.8 A for two circuit
breakers with the maximum possible number of external cmodules.
Catalog number
Power supply Catalog No.
120/230 V AC / 24 V DC, 2.5 A WLSITOP25
120/230 V AC / 24 V DC, 3.8 A WLSITOP1
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