CIRCUTOR computer MAX Plug&Play series - Manual (Page 11)

M98228201-03-14A
computer MAX 6 / computer MAX 12
- 11 -
4.2 DEVICE INSTALLATION
4.2.1 Mechanical Installation
Mechanically, the device is intended to be mounted attached to the front door of the cabinet. The fitting
hole must be according to DIN 43 700, (dimensions 138
+1 x138 +1 mm).
4.2.2 Connections
Before connecting the supply to the device check the following items:
The installation and maintenance of the device must be carried out by specialised and dully
trained staff, according to National Electric Codes and Rules and International Standards
All the connections must be at the inner part of a protection cabinet.
Notice that when the device is connected to supply, the voltage at certain terminals can be
hazardous and cause electric shock in case of contact. Opening the electrical cabinet or
removing certain covers can compromise the user safety and should only be done by
qualified and authorized staff.
The Computer MAX devices are used together with capacitor banks, which can remain
charged after supply disconnection. In order to avoid shock hazard, wait during 5 minutes
after supply disconnection before any manipulation inside the equipment cabinet.
Computer MAX devices require current sensing of the installation. A current transformer (CT) must be
installed externally to perform this function. Usually the current ratio of the CT is I
n
/ 5 A, where In must
be at least 1,5 times the MAXimum expected load current.
The CT must be installed at the incoming supply line (point of coupling of the user), so that it measures
the total current of all the loads, including also the compensation capacitor bank (see fig. 4.1)
The CT should be installed preferably in phase L1, while the voltage measuring terminals of Computer
MAX should be connected to phases L2 and L3 (see schematics in figs. 4.2 and 4.3). It’s important to
respect the connection senses of P1-P2 and S1-S2 shown in the above mentioned figs, otherwise the
phase difference will have to be corrected by adjusting the device according to set-up procedure indicated
in paragraph 5.17.
RIGHT CONNECTION WRONG CONNECTIONS
The CT measures the whole
current of loads + capacitor bank.
In case of malfunction check that
the CT is not shortcircuited
TC
S1
S2
P1
P2
LOAD CAPACITORS
If CT is placed in this position,
NONE of the CAPACITOR
STAGES WILL CONNECT.
The equipment does not regulate
properly.
If CT is placed in this position
ALL THE CAPACITOR STAGES
WILL CONNECT.
WARNING! This situation may
cause overcompensation,
resonance and overcurrent
Fig. 4.1.- Placement of current transformer (CT)