Siemens 7SR18 Solkor - Case; Figure 2.2-1 Front View of Relay; Figure 2.2-2 Rear View of Relay; Figure 2.2-3 Earth Connection Symbol

7SR18 Description Of Operation
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2.2 Case
The relays are housed in cases designed to fit directly into standard panel racks. The case has a width of 156 mm
and a height of 177 mm (4U). The required panel depth (with wiring clearance) is 287 mm.
The complete relay assembly is withdrawable from the front of the case. Contacts in the case ensure that the CT
circuits and normally closed contacts remain short-circuited when the relay is removed. To withdraw the relay,
remove the plastic fascia cover by rotating the two securing pins and withdraw using the plastic handles. The
relay should not be carried using these handles. The relay should only be held by the top and bottom plates and
the user should not touch the exposed PCB’s.
Figure 2.2-1 Front View of Relay
The rear terminal blocks comprise M4 female terminals for wire connections. Each terminal can accept two 4 mm
crimps.
Figure 2.2-2 Rear view of Relay
Located at the top rear of the case is a screw clamp earthing point, this must be connected to terminal B28 and
directly to the main panel earth. This connection point is indicated by the following symbol.
Figure 2.2-3 Earth connection Symbol