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Chapter 1) 7SR158 Description of Operation
The only 'action' that is permitted is to reset the Fault Data display, latched binary outputs and LEDs by using the
TEST/RESET
.
button
Figure 2-4 Relay with transparent cover and push buttons
2.4
Power Supply Unit (PSU)
Relay PSU options allow the relay to be directly connected to dc system rated from 24V to 60V or 80 to 250V.
The 80- 250Vdc PSU can also be used with 115V AC supplies. For consistency and safety it is advised that AC
connections to the auxiliary supply are made with the Live connection to the +ve terminal and Neutral connection
to –ve. The device will operate normally for reversed polarity DC auxiliary voltages.
In the event of the station battery voltage level falling below the relay minimum operate level the PSU will
automatically switch itself off and latch out – this prevents any PSU overload conditions occurring. The PSU is
reset by switching the auxiliary supply off and on.
©2014 Siemens Protection Devices Limited
Chapter 1) Page 13 of 38
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