Mitsubishi Electric MELDASMAGIC64 Connection Manual page 23

Please refer to following method for heat radiation countermeasures method.
<Hypothetical conditions>
(1) Electric cabinet ambient temperature
(2) Internal temperature rise value
(The value for the conventional NC is 10°C, but this temperature must be set to 10°C or
less (target value 5°C) for the MELDASMAGIC64.)
(3) Average temperature in electric cabinet : T
Procedures for heat design and verification
Calculate total heat generation of
each mounted unit (W)
Calculate electric cabinet's
cooling capacity (W1)
W≤W1
Comparison of W and W1
Selection of heat exchanger
Mounting design
Collection of internal temperature rise
distribution data
∆ ∆
Tm ≤
Td
Improvements
Mounting example and introduction to temperature (∆T) measurement locations (reference)
: Temperature rise measurement
points (example)
Heat exchanger
3. Installation
3.3 Installation
Example of heat radiation countermeasures
>
W W1
Evaluation
∆ > ∆
Tm Td
Completion
Relay panel, etc.
Air inlet
Air outlet
: T
a
: ∆T
d
+ ∆T
a d
<Supplement>
(1) Refer to "3.1 General Specifications" for the
heat generated by each unit.
(2) Enclosed electric cabinet (thin steel plate)
cooling capacity calculation equation
W1 = U × A × ∆T
2
U : 6W/m
with internal circulation fan
2
4W/m
without internal circulation fan
A : Effective heat radiation area (m
(Area where heat can be radiated from
electric 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 electric cabinet
(eliminate heat spots)
* Collect hot air at suction port in heat
exchanger panel.
(4) Evaluation standards for internal
temperature rise distribution data
∆Tm (average value)
∆T
max (maximum value)
m
R (inconsistency ∆T
(Evaluate existence of heat spots)
∆T
: Internal temperature rise
m
measurement value
External
air flow
11
d
× °C
× °C
∆T
≤
d
≤ (∆T + 5) °C
d
max - ∆T
min) ≤ 6°C
m m
Internal
air flow
2
)