EMK
series
Instructions Manual M98118701-03-19A 11
5.3.1 Power circuit
•
Connect input terminals L1, L2 and L3 (power circuit supply) to the grid using proper sized
cables in accordance with the National Electric Code or LVD. Generally, the phase cables use
the following colour code: L1 (black), L2 (brown), L3 (grey). If a 230 V auxiliary voltage is
required, we can use an internal 400V/230V transformer or use the neutral and connect it to
terminal N (blue colour cable).
•
In order to determine the size of the phase cables, the user must consider a maximum
expected current equal to 1,5 times the
I
max
shown on the equipment's label. In case of
feeding the neutral cable to obtain the auxiliary voltage, U
aux
, it shall have a cross section of at
least 1.5 mm
2
.
5.3.2 External isolation and protection elements
•
In case the capacitor bank does not have an internal switch or circuit breaker, it must be
connected to a line with an external switch or circuit breaker.
The protection elements, isolation switches and/or switches that are added
externally to the capacitor bank must be of a minimum size to withstand a current
1.5 times greater than the
I
max
indicated on the label
If an earth leakage protection for the capacitor bank is installed, its sensitivity and
trip delay must be adjustable.
•
For capacitor banks equipped with a standard regulator measuring the current only in one of
the supply phases, we advise installing the current transformer (CT) in the phase connected to
L1 (black cable). The CT's S1 and S2 outputs must be connected then to the terminals with
the same name on the capacitor bank. For more details about the connection of the CT, see
paragraph 5.3.5
5.3.3 Auxiliary control voltage
•
The auxiliary control circuits include those related to the power supply of the
CPC
controllers
and other control or protection devices and ventilation units. The
CPC
controllers, up to 400 V,
usually are supplied at 400 V
AC
from phase to phase voltage. In other applications supplied
above 440 V and up to 690V, the CPC must be supplied from an auxiliary voltage of 230 V
AC
•
The auxiliary power supply of 230 V, can be obtained from an internal V
primary
/230V transformer
or using phase-neutral from a 400V supply (connect neutral to terminal N with a blue colour
cable).
5.3.4 Earth cable connection
•
Connect the earth terminal of the capacitor bank, placed inside the equipment's cabinet (see
Fig. 4-2) to the external earth connection. The earth cable cross section shall be selected in
accordance with the admissible current limits established in the National Electric Code or LVD
5.3.5 Connecting the current transformer (CT)
A current transformer (CT), external to the capacitor bank, must be installed to
measure the total of load current plus the capacitor bank current (see Fig. 4-1).
The standard transformer must have a nominal output of 5A at the secondary.
We recommend connecting the CT to phase L1 , with the cable running from line to
load in the direction P1 to P2 , and connecting the secondary (terminals S1, S2) to
the terminals with the same name on the capacitor bank (see Fig. 5-1).
Avoid the flow of current through the CT's primary (P1-P2) before connecting the
secondary side to the capacitor bank's S1 and S2 terminals. If the CT must be
installed while the installation is running, short-circuit S1 and S2 while they are not
connected to the capacitor bank.