Connection To Main Power Supply - Icar MICROmatic HP10 Manuel D'installation Et D'opération

4. CONNECTION TO MAIN POWER SUPPLY

The three phases of the mains should be connected, via adequately sized power cables (refer to annex E), to
the terminals of the load disconnect switch marked by the letters L1, L2 and L3 (R, S and T) respectively.
Connect the earthing system (ground) via suitably sized cable, as prescribed by regulations, to the earth
terminals located inside the various units.
We stress that the earth conductor must never be electrically interrupted neither inside nor outside the unit.
Connect terminals K and L to the secondary of a current transformer with secondary current 5A inserted on
phase L1 (R) (see Attachment B). In order to ensure correct operation of the automatic control it is essential for
the unit to be connected as described in the above attached document which also illustrates some typical
connection errors.
The current transformer, besides being of high quality, is a measuring instrument and not merely a display
instrument, therefore it should possess certain characteristics, namely:
Apparent power
The Apparent Power of the current transformer (expressed in VA) should be such as to meet the levels of self-
consumption at both the current input of the controller used and the connecting cable (see table below).
2
Cable size (mm )
2,5 
4
6
10
16
For each 10°C variation in temperature, the VA absorbed by the cables are

increased by 4%; the values given above are deduced from typical resistances
of flexible cables, class 5
Minimum size of connection of cables between current transformer and

controller.
Current transformer amperage
The primary amperage of the current transformer should be determined by the user solely in relation to the
current drawn by the load whose phase is to be corrected.
Location
Position the current transformer upstream of the entire load, capacitor bank included, on phase L1 (R) referred
to the power factor correct unit, but downstream of any fixed capacitors dedicated to power factor correction of
the transformer MV/LV.
Install the current transformer on the mains with the side marked by the letter "K" facing the power supply
source and the side marked by the letter "L" facing the load (side where there is also the power factor correction
system).
The system is now in condition for putting into service. However, first of all it is absolutely necessary to check
that it is suitable for the conditions of the mains to which it has been connected.
Check, with appropriate measurements, that the mains voltage is congruent with the nominal characteristics
given on the nameplate.
After connection and before powering up the system, it is recommended to make sure that no foreign matter
produced by the machining operations, have been lodged inside the unit.
It is also important to remember to refit the guards on the switch or disconnect switch provided on the unit.
VA per metre of cable at
20°C 
0,41
0,254
0,169
0,0975
0,062
17