Rittal enclosure cooling unit
9
4 Assembly and connection
EN
4.5
Notes on electrical installation
When performing the electrical installation, it is important
to observe all valid national and regional regulations as
well as the provisions of the responsible power supply
company. The electrical installation may only be carried
out by a qualified electrician who is responsible for com-
pliance with the applicable standards and regulations.
4.5.1
Connection data
– The connected voltage and frequency must corre-
spond to the values stated on the rating plate.
– The cooling unit must be connected to the mains via
an all-pin isolating device, which ensures at least
3 mm contact opening when switched off.
– No additional temperature control may be connected
upstream of the unit at the supply end.
– Install the protective device specified on the rating
plate to protect the line and equipment from short-cir-
cuits.
– The mains connection must ensure low-noise poten-
tial equalisation.
4.5.2
Overvoltage protection and supply line load
– The unit does not have its own overvoltage protection.
Measures must be taken by the operator at the supply
end to ensure effective lightning and overvoltage pro-
tection. The mains voltage must not exceed a toler-
ance of ±10%.
– In accordance with IEC 61 000-3-11, the unit is in-
tended solely for use at sites with a continuous cur-
rent-carrying capacity (incoming mains power supply)
of more than 100 A per phase and with a supply volt-
age of 400/230 V. If necessary, the power supply
company must be consulted to ensure that the contin-
uous current-carrying capacity at the point of connec-
tion to the public grid is sufficient for connection of
such a unit.
– The fans and compressors in single- and three-phase
units are intrinsically safe (thermal winding protection).
The same also applies to all transformer versions and
to special-voltage units which are likewise equipped
with a transformer.
– Install the protective device specified on the rating
plate to protect the line and equipment from short-cir-
cuits (miniature circuit-breaker with appropriate char-
acteristic – e.g. "K" characteristic – or gG standard
type slow fuse, circuit-breaker for plant or transformer
protection). Select a suitable circuit-breaker in accord-
ance with the information specified on the rating plate:
Set it to the minimum specified value. This will achieve
the best short-circuit protection for cables and equip-
ment.
Example: Specified setting range 6.3 – 10 A; set to
6.3 A.
4.5.3
Three-phase devices
– The electrical connection for devices in the three-
phase version MUST be made with a clockwise rotat-
ing field.
– The three-phase version must be connected to a TN
network with star earthing via a circuit-breaker for
plant protection (current setting as per the rating
plate). Three-phase units with special voltages must
be protected with a circuit-breaker for transformer
protection (category AC-3) as per the rating plate.
– Units designed for three phase 400/460 V feature ad-
ditional monitoring of the rotary field or the absence of
a phase. If the rotary field is incorrect or a phase is ab-
sent, the unit will not run.
4.5.4
Door limit switch
– Each door limit switch must only be assigned to one
cooling unit.
– Several door limit switches may be connected in par-
allel to one cooling unit.
– The minimum cross-section for the connection cable
is 0.3 mm
2
for a cable length of 2 m.
We recommend the use of a shielded cable.
– The line resistance to the door limit switch must not
exceed a maximum of 50 Ω.
– The door limit switch only supports a floating connec-
tion; no external voltages.
– The contact of the door limit switch must be closed
when the door is open.
The safety extra-low voltage for the door limit switch is
provided by the internal power pack: Current approx.
30 mA DC.
Connect the door limit switch to terminals 1 and 2 of
the connector.
4.5.5
Notes on the flicker standard
The flicker limits specified in standard EN 61 000-3-3 or
-3-11 are adhered to, provided the supply impedance is
less than approx. 1.5 Ω.
Where necessary, the unit operator should measure the
connected impedance or consult the responsible power
supply company. If there is no way of influencing the
supply impedance and sensitive installed components
(e.g. BUS) are subjected to interference, a line reactor or
starting-current limiting device should be connected up-
stream of the cooling unit to restrict the startup current
of the cooling unit.
4.5.6
Potential equalisation
If, for EMC reasons, the unit is to be integrated into the
customer’s existing potential equalisation system, a
conductor with a larger nominal cross-section can be
connected to the potential equalisation connection point
(attachment points) on the roof-mounted cooling units.
According to the standard, the PE conductor in the
mains connection cable is not classified as an equipo-
tential bonding conductor.
Summary of Contents for Rittal 3273 Series
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