Mitsubishi Electric Melservo-J3 Series MR-J3-B, Инструкция по эксплуатации

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13 - 5
13. CHARACTERISTICS
(2) Heat dissipation area for enclosed servo amplifier
The enclosed type control box (hereafter called the control 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 maximum 55
(131 ) limit.) The area required for heat dissipation can be calculated by Equation 13.1.
P
A
K T
............................................................................................................................................. (13.1)
where, A : Heat dissipation area [m 2 ]
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 Equation 13.1, assume that P is the sum of all losses
generated in the control box. Refer to Table 13.1 for heat generated by the servo amplifier. "A" indicates the
effective area for heat dissipation, but if the control box is directly mounted on an insulated wall, that extra
amount must be added to the control box's surface area.
The required heat dissipation area will vary wit the conditions in the control box. If convection in the control
box is poor and heat builds up, effective heat dissipation will not be possible. Therefore, arrangement of the
equipment in the control box and the use of a cooling fan should be considered.
Table 13.1 shows the area required by each servo amplifier for heat dissipation in the control box when the
servo amplifier is operated at the ambient temperature of 40 (104 ) under rated load.
(Outside)
(Inside)
Air flow
Fig. 13.2 Air flow in an enclosed type control box
When air flows along the wall inside and outside the control box, the temperature gradient will be large, and
therefore the heat exchange will be more effective.