10 - 5
10. 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 at the ambient temperature of 40 . (With a 5
(41 ) safety margin, the system should operate within a maximum 55 (131 ) limit.) The necessary
enclosure heat dissipation area can be calculated by Equat ion 10.1.
P
AKT
.............................................................................................................................................(10.1)
where, A : Heat dissipation area [m2]
P : Loss generated in the control b ox [W]
T : Difference between internal and ambient temperatures [ ]
K : Heat dissipation coeffic ient [5 to 6]
When calculating the heat dissipation area with Eq uation 10.1, assume that P is the sum of all losses
generated in the enclosure. Refer to Table 10.1 for heat generated by the ser vo 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 var y wit the conditions in the enclosure. If convectio n 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 c ooling fan should be considered.
Table 10.1 lists the enclosure dissipation area f or each servo amplifier when the servo amplifier is oper ated
at the ambient temperature of 40 (104 ) under rated load.
(Outside) (Inside)
Air flow
Fig. 10.2 Temperature distribution in enclosure
When air flows along the outer wall of the enc losure, effective heat exchange will be possible , because the
temperature slope inside and outside the encl osure will be steeper.