Hardware and Connections
2-8
7SJ63 Manual
C53000-G1140-C120-1
Terminal Block for
Current
Connections
There is one version of a terminal block for current connections to a 7SJ63. The ter-
minal block is illustrated in Figure 2-7.
Figure 2-7
Terminal Block of Threaded Terminals for Current Connections - Rear View
The correlation between threaded terminals and connection numbers is the same for
both the current connections and the voltage connections. Compare Figures 2-6 and
2-7.
In the terminal block for current connections, the terminals are grouped in pairs. Two
neighboring terminals such as terminals 5 and 6 form one pair. The terminal block con-
tains four pairs, one for each of the input currents.
The current transformers present low burden to the main current transformers.
When the I/O board is extracted, the current circuits are automatically short-circuited
prior to the separation of the current transformers from the current circuits. This pre-
vents hazards to service personnel due to the high voltages that can occur if the sec-
ondary circuits of the current transformers are open.
When the I/O board is properly inserted into the case of the 7SJ63, the short-circuits
of the current paths are removed after the transformers of the device are connected
to the terminal-pairs.
The short-circuit feature of the 7SJ63 is an important and reliable safety feature; how-
ever, the feature does not relieve the user from exercising proper care when working
with current transformer secondary circuits.
Connections to
Voltage Terminals
Ring or spade lugs may be used. To maintain proper isolation of the circuits, the lugs
must be insulated or insulating sleeves must be fitted to cover the exposed crimp
zones.
The following must be observed:
Connections with Cable lugs: inner diameter of lugs, 4 mm;
maximum outer width of lugs, 10 mm;
conductor with cross-section of 1 mm
2
to 2.6 mm
2
or AWG 17 to 13.
Use copper wires only!
Cable lugs of series PIDG from AMP Co. are recommended, e.g.
Ring cable lug: PIDG PN 320 565–0
Spade lug:
PIDG PN 321 233–0.
8 Terminal
1
2
3
4
5
6
7
8
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