Dx Enclosures; Environmental Conditions - Eaton MTL5501-SR Instruction Manual

5
Enclosures are usually selected on the basis of the number of units they will accommodate and
Table 5.1 shows the capacity of each of the enclosures. Figure 5.2 shows each type of enclosure
containing MTL5500 modules.
Table 5 .1: DX range of enclosures - module capacities
* Use these figures when two IMB57 mounting brackets for tagging/earth-rail accessories are included.
Note: The user should be aware that some workshop preparation may be required for the cable gland
plates before the enclosure is ready for on-site installation.
5 .1
Environmental conditions that should be taken into account when installing DX enclosures include:-
5 .1 .1
Figure 5 . 1 : Graph depicting outside enclosure temperature limits for DX enclosures used
The maximum outside enclosure temperature depends upon the total power dissipated by the
installed modules which, in turn, depends upon their number and type. It can also be influenced by
the Authority whose standards may need to be applied to the system, e.g. Baseefa, Factory Mutual
Research Corporation, Canadian Standards Association.
Figure 5.1 shows, in graphical form, the maximum outside enclosure temperatures (T
levels of power dissipation.
The graph was derived from the following equation and should be used to calculate accurately the
suitability of any particular mix of modules.
P = total power (watts) dissipated by modules in an enclosure
k = is a dissipation constant for a given enclosure and module . Select the relevant value from
1
Table 5.2.
(60°C is the temperature inside the enclosure)
12

DX ENCLOSURES

Enclosure
DX070
DX170
(DX430)

Environmental conditions

Maximum ambient temperature limits
Storage temperatures
Humidity
Corrosion resistance
Flammability
Impact resistance
Chemical resistance
Maximum outside enclosure temperature limits
with MTL5500 isolators
60
50
40
30
20
10
0
10
T = 60°C - ∂T where ∂T = k
MO
Number of MTL5500 isolators
16mm mounting pitch
4 (2*)
10 (8*)
26 (24*) no longer available
See section
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
Enclosures
DX070
DX170
DX430
20 30 40
Power dissipation (watts)
x P
1
) for given
MO
INM 5500 Rev 10