Power Supply Unit (Psu); Figure 1-14 Relay With Standard Transparent Cover; Figure 1-15 Relay With Transparent Cover And Push Buttons - Siemens 7SR11 Manual

If access is required to view the menus without removing the cover, an alternative transparent cover with push
buttons may be ordered. With the cover in place the user will only has access to the
buttons, allowing all areas of the menu system to be viewed, but preventing setting changes and control actions.
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 1-15 Relay with transparent cover and push buttons

2.4

Power Supply Unit (PSU)

The relay PSU can be ordered with two different nominal power supply ranges
a) 24V to 60V DC
b) 80V to 250V DC, 110/115 V rms AC
The rated auxiliary supply voltage (Vx) is clearly stated on the relay fascia rating label, see below.
7SR1 devices manufactured before February 2012, prior to hardware version /CC, cannot be operated from AC
supplies and the rating is shown as DC only. From hardware version /CC, devices are available which will operate
normally for DC or AC supplies. These 80-250 V DC/110/115 V AC devices of hardware version /CC or later will
operate normally for reversed polarity DC auxiliary voltages – devices of previous hardware versions and 24-60V
DC devices will not start-up with reversed polarity supplies.
All binary inputs are polarity conscious and will not operate if the DC supply polarity is reversed. For consistency
and safety it is advised that AC connections for auxiliary supply and binary inputs are made with the Live
connection to the +ve terminal and Neutral connection to –ve.
In the event of the supply 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.
©2012 Siemens Protection Devices Limited

Figure 1-14 Relay with standard transparent cover

7SR11 & 7SR12 Description Of Operation
▼ TEST/RESET►
and
Chapter 1 Page 17 of 76