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3. INSTALLATION
3.3 Countermeasures against Heat Radiation
I - 11
3.3 Countermeasures against Heat Radiation
Please refer to the following procedures for heat radiation countermeasures.
Example of heat radiation countermeasures
<Hypothetical conditions>
(1) Average temperature in cabinet : T ≤ 55C°
(2) Cabinet peripheral temperature : Ta
≤ 0C° to 45C°
(3) Internal temperature rise value :
∆T = T - Ta(max) = 10 C°
Procedures for heat design
and verification
<Supplement>
(1) Refer to section "3.1 General Specification" for the heat
generated by each unit.
(2) Enclosed cabinet (thin steel plate) cooling capacity (W1)
calculation equation
W1
= U x A x ∆T
U: 6W/m
2
× C°
---with internal circulation fan
4W/m
2
× C°
---without internal circulation fan
A: Effective heat radiation area (m
2
)
∆T: Internal temperature rise value (10C°)
(Area where heat can be radiated from
cabinet)
<Caution>
When calculating the effective heat radiation area, do not
include the parts that contact other objects.
(3) Points of caution for heat radiation countermeasures
when designing mounting state
* Consider convection in cabinet (eliminate heat spots)
* Collect hot air at suction port in heat exchanger cabinet.
(4) Criterion for internal temperature rise distribution data
∆T (average value) ≤ 10C°
∆Tmax (maximum value) ≤ 15C°
R (inconsistency
∆Tmax – ∆Tmin) ≤ 6C°
(Evaluate existence of heat spots)
Comparison between
W and W1
Calculate total heat generated by
each mounted unit (W)
Calculate cabinet’s cooling capacity
(W1)
Selection of heat exchanger
Mounting design
Collection of internal temperature
rise distribution data
Evaluation
Improvements
Completion
W ≤ W1
W > W1
∆
T ≤ 10C°
∆T > 10C°
Refer to section "3.1 General Specification" for the heat generated by each unit.
If heat accumulates at the top of the control unit, install a circulation fan in the operation box.
If the following conditions are not satisfied, install a circulation fan in the cabinet.
Criterion for internal temperature rise distribution data
∆T (average value) ≤ 10°C
∆Tmax (maximum value) ≤ 15°C