CIRCUTOR OPTIM-EMS-C Series - Manual (Page 15)

3.9.- CURRENT TRANSFORMER (CT) CONNECTION
A current transformer (CT) outside the capacitor bank must be installed to
measure the total load current, plus that of the capacitor bank itself
( Figure 8 ).
The standard transformer must have a nominal output of 5 A at the secondary.
We recommend connecting the CT to phase L1 in the direction of the current flow
from P1 to P2 ( Figure 8 ) and connecting the secondary (terminals S1, S2) to the
capacitor bank terminals with the same name ( Figure 8 ).
Avoid the flow of current through the CT's primary before connecting the second-
ary to the S1 and S2 terminals of the capacitor bank.
If the CT must be installed while the installation is under load, short-circuit S1 and
S2 while they are not connected to the capacitor bank.
The current value of the CT primary winding must be equal to or slightly greater than the size of
the mains switch of the installation. Therefore, the CT must be able to measure the maximum
current expected to be consumed by all the loads being compensated.
Figure 8: Installation of the external current transformer (CT).
The connection point of the CT for a capacitor bank that compensates an entire installation is
after the mains switch of the installation.
To prevent excessive attenuation of the signal, it is recommended that the minimum cross-sec-
tion of the secondary winding cable (terminals S1, S2) is at least 2.5 mm 2 .
15 Instruction Manual
OPTIM EMS-C series