Mitsubishi Electric MELDAS MDS-R Series, Specifications And Instruction Manual

Page: 135 / 362

6. Installation
6 - 12
The following shows a calculation example for considering heat radiation countermeasures.
<Control panel outline dimension (assumption) >
When installing four units which have the heating value in the panel of 15W
Top of panel inside Fan for agitating
600
300
600
Heat radiation area (A): When a bottom section contacts with a machine
A = 0.6 x 0.3 + 0.6 x 0.6 x 2 + 0.6 x 0.3 x 2 = 1.26 (m
2
)
(Top face) (Front/back face) (Side face)
*Actually, sections contacting other objects are excluded.
Heating value in panel (W): when installing four units which are 15W
W = 15 x 4 = 60 (W)
<Considering nec essity of agitating f an>
1 Temperature standard
(1) Standard of temperature in panel (around each unit) T

55°C
(2) External peripheral temperature Ta = 0 to 45°C
(3) Internal temperature rise value

T = T - Ta(MAX) = 10°C
2 C
ooling
capacity of control panel (W1)
W1 = U x A x

T

T = Internal temperature rise value (=10°C)
U = 6W/m
2

°C (with internal agitating fan)
4W/m
2 
°C (without internal agitating fan)
A = Effective heat radiation area (m
2
)
(1) With internal agitating fan W1 = 6 x 1.26 x 10 = 75.6 (W) > 60 (W)
Internal fan is
required.
(2) Without internal agitating fan W1 = 4 x 1.26 x 10 = 50.4 (W) < 60 (W)
POINT
Measure an actual internal temperature, and install a fan or heat exchanger
which agitates the heat at the top of the unit if the temperature rise exceeds
10°C.
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