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9.CHARACTERISTICS
(2) Heat dissipation area for enclosed servo amplifier
The enclosed control box (hereafter called the control box) which will contain the servo ampli-
fier should be designed to ensure that its temperature rise is within +10°C at the ambient tem-
perature of 40°C. (With a 5°C (41°F) safety margin, the system should operate within a
maximum 55°C (131°F) limit.) The necessary enclosure heat dissipation area can be calcu-
lated by Equation 9-1:
P
A =
K • ∆T
where, A: Heat dissipation area [m ]
P: Loss generated in the control box [W]
∆T: Difference between internal and am-
bient temperatures [°C]
K: Heat dissipation coefficient [5 to 6]
When calculating the heat dissipation area with
Equation 9-1, assume that P is the sum of all
losses generated in the enclosure. Refer to
Table 9-1 for heat generated by the servo am-
plifier. "A" indicates the effective area for heat
dissipation, but if the enclosure is directly in-
stalled on an insulated wall, that extra amount
must be added to the enclosure's surface area.
The required heat dissipation area will vary wit
the conditions in the enclosure. If convection in the enclosure is poor and heat builds up,
effective heat dissipation will not be possible. Therefore, arrangement of the equipment in
the enclosure and the use of a fan should be considered.
Table 9-1 lists the enclosure dissipation area for each servo amplifier when the servo am-
plifier is operated at the ambient temperature of 40°C (104°F) under rated load.
(9-1)
........................................
2
9– 5
(Outside)
(Inside)
Fig. 9-1 Temperature Distribution in
Enclosure
When air flows along the outer wall of the
enclosure, effective heat exchange will
be possible, because the temperature
slope inside and outside the enclosure
will be steeper.
Air flow
9
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