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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 secondary terminal block 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.
The Siemens power supply listed below may be used to supply power to a single circuit breaker. A second circuit breaker requires its own
power supply.
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: minimum 3.7A per circuit breaker
- EMC according to: IEC 61000-4-4, 4kV on main side; IEC 61000-4-5, 4kV line-to-earth, 2kV line-to-line.
Catalog number
Power supply Catalog No. MLFB
120/230 VAC / 24 VDC,
3.8A SITOP PSU100C NEC CLASS 2
WLSITOP1 6EP1332-5BA20
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