Operating Instructions; Safety Precuations; Figure 3.1 Connection To C.t. In Holmgreen Circuit - Siemens 7SN71 Instruction Manual

Transient earth-fault relay 7SN71
3

Operating instructions

3.1

Safety precuations

All safety precautions which apply for work in electri
cal installations are to be observed during commissio
ning.
3.2 Connection to auxiliary power supply
Figure 3.1 shows the connection to a current transfor
mer set in Homgreen circuit.
Here, the starpoint at the line-side of the c.t.s must
be connected to terminal 1 (2B1) or 2 (1B2), while the
starpoint at the bus-bar side of the c.t.s must be con
L1
L2
L3
Figure 3.1 Connection to c.t. in Holmgreen circuit
Siemens AG March 1997
Instruction Manual
nected to terminal 3 (1B1). The three phase voltages
V , V
L1
5 (2A2) and 6 (2A3), respectively. The earthed starpo
int of the c.t. is connected ot terminal 7 (2A4).
terminals for
flash mounting
terminals for
surface mounting
other protection relay
e.g. O/C relay
L-
Operating instructions
Order No.: E50410-A0007-U501-A1-7691
and V are connected to terminals 4 (2A1),
L2 L3
3
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