13 - 5
13 CHARACTERISTICS
(2) Heat dissipation area for enclosed servo amplifier
The enclosed control box (hereafter called the con trol box) which will contain the servo amplifier should be
designed to ensure that its temperature rise is within 10 ( 50 ) at the ambient temperature of 40
(104 ). (With a 5 (41 ) safety margin, the system should operate within a m aximum 55 (131 ) limit.)
The necessary enclosure heat dissipation area c an be calculated by Equation 13.1.
P
AKT
.............................................................................................................................................(13.1)
where, A : Heat dissipation area [m2]
P : Loss generated in the control box [W]
T : Difference between internal and ambient temperatures [ ]
K : Heat dissipation coefficient [5 to 6]
When calculating the heat dissipation area with E quation 13.1, assume that P is the sum of all losses
generated in the enclosure. Refer to Table 13.1 for heat generated b y the servo amplifier. "A" indicates the
effective area for heat dissipation, but if the enclosure is directl y installed on an insulated wall, that extra
amount must be added to the enclosure's surface area.
The required heat dissipation area will vary wit t he conditions in the enclosure. If convection in t he
enclosure is poor and heat builds up, effective heat dis sipation will not be possible. Therefore, arrangement
of the equipment in the enclosure and the use of a cooling fan should be considered.
Table 13.1 lists the enclosure dissipation area for each servo amplifier when the servo amplifier is operat ed
at the ambient temperature of 40 (104 ) under rated load.
(Outside) (Inside)
Air flow
Fig. 13.2 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 encl osure will be steeper.