Handling Precautions - Mitsubishi Electric KD Series User Manual

2-7 Handling precautions

【 Thermal management 】
TM-XG537C
This product will operate between +5 to +50 ℃ of environmental
temperature (Ta), under natural air cooling circumstance.
In other circumstance, such as the product temperature may be
raised by the incoming heat from the peripheral devices and/or the
connecting part, check the case temperature Tw (refer left diagram),
and use the product while the Tw to be kept between +5 to +70 ℃ .
If the case temperature exceeds the specified temperature, apply an
Tw = Temperature of a case
appropriate cooling or forced air cooling as follows.
A variable of flow rate u (m / s) required for air cooling is ambient
temperature and operating conditions Ta. Flow rate u is calculated
from the equation #1. Valuables of Air quantity v (m
in cross-sectional area of this product A
u(m/s). The air amount is calculated from the equation#2. The
constants and the equations are followings.
Equation #1
Equation #2
Symbol
Q
L
A
ε
Tw
σ
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Q
－ ４・ ε ・ σ ×
Ａ・ (Tw － Ta)
ｕ ＝
3.92
V ＝ Aair × ｕ
Explanation Unit
Heat Base(23kHz) W
value
Medium(43kHz)
Length m
Surface area m2
Emissivity -
Max temperature of case K
Stefan-Boltzmann's constant W/m2 ・ K4
3 / s) are a space
(m 2 ) and wind speed
air
3 2
Tw ＋ Ta
2
× Ｌ
KD6R309MX KD6R617MX KD6R926MX
29.3 55.6 94.8
43.7 81.1 144.6
0.37 0.68 0.99
0.16 0.27 0.38
0.77
343.15
5.6687E-08
41