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5 - ELECTRICAL CONNECTION
Please refer to the certified dimensional drawings, supplied with
the unit.
5.1 - Power supply
The power supply must conform to the specification on the chiller
nameplate. The supply voltage must be within the range specified
in the electrical data table. For connections refer to the wiring
diagrams and the certified dimensional drawings.
WARNING: Operation of the chiller with an improper supply
voltage or excessive phase imbalance constitutes abuse
which will invalidate the Carrier warranty. If the phase
imbalance exceeds 2% for voltage, or 10% for current, contact
your local electricity supply at once and ensure that the chiller
is not switched on until corrective measures have been taken.
5.2 - Voltage phase imbalance (%)
100 x max. deviation from average voltage
Average voltage
Example:
On a 400 V - 3 ph - 50 Hz supply, the individual phase voltages
were measured to be:
AB = 406 V; BC = 399; AC = 394 V
Average voltage = (406 + 399 + 394)/3 = 1199/3
= 399.7 say 400 V
Calculate the maximum deviation from the 400 V average:
(AB) = 406 - 400 = 6
(BC) = 400 - 399 = 1
(CA) = 400 - 394 = 6
The maximum deviation from the average is 6 V. The greatest
percentage deviation is: 100 x 6/400 = 1.5 %
This is less than the permissible 2% and therefore acceptable.
5.3 - Power connection/disconnect switch
Units
30XB-250 to 1000
30XB-1100 to 1700
Motor
Connection points
1 per unit
1 for circuit 1
1 for circuit 2
5.4 - Recommended wire sections
Wire sizing is the responsibility of the installer, and depends on the
characteristics and regulations applicable to each installation site.
The following is only to be used as a guide-line, and does not make
in any way liable. After wire sizing has been completed, using the
certified dimensional drawing, the installer must ensure easy
connection and define any modifications necessary on site.
The connections provided as standard for the field-supplied power
entry cables to the general disconnect/isolator switch are designed
for the number and type of wires, listed in column 2 of the table
on the next page.
The calculations are based on the maximum machine current (see
electrical data tables).
The calculations for favourable and unfavourable cases are based
on the maximum current for each unit (see electrical data tables).
For the design the standardised installation methods in accordance
with IEC 60364 are used: PVC (70 °C) or XLPE (90 °C) insulated
cables with copper core; arrangement to comply with table 52c of
the above standard. The maximum temperature is 46 °C. The given
maximum length is calculated to limit the voltage drop to 5%.
IMPORTANT: Before connection of the main power cables
(L1 - L2 - L3) on the terminal block, it is imperative to check the
correct order of the 3 phases before proceeding to the
connection on then terminal block or the main disconnect/
isolator switch.
5.5 - Power cable entry
The power cables can enter the 30XB control box from below or
from the unit side. For 30XB unit sizes 600 to 1700 the control box
that includes the power supply cable connec-tion terminal is located
in the lower part of the unit. In this case the control box is raised
by 120 mm compared to the lowest point of the chassis.
The cable entry point depends on the unit configuration:
1. Unit raised from the ground (e.g. installation on sup-port rails):
It is recommended to enter the power cables from below the
control box. A removable aluminium plate below the control
box allows introduction of the cables.
2. Unit placed on the ground: For power cable entry from below
the control box ensure that the cable bend radius is compatible
with the connection space available in the control box. If not,
an aluminium plate on the control box face allows introduction
of the cables.
For units with three circuits with option 81 (single power connection
point) the connection must be made from below the unit.
IMPORTANT: Check the cable bend radius for cable entry into
a control box, located in the lower part of the unit.
Refer to the certified dimensional drawing for the unit.
39
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