Mitsubishi Electronics MR-J2S- CL 2 Temperature distribution in enclosure, Characteristics, 13

13.CHARACTERISTICS

(2)Heat dissipation area for enclosed servo amplifier

The enclosed 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 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 Equation 13.1:

	P				(13.1)
A K			T
					: Heat dissipation area [m2]
where, A
		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 enclosure. Refer to Table 13.1 for heat generated by the servo amplifier. "A" indicates the effective area for heat dissipation, but if the enclosure is directly 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 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 13.1 lists the enclosure dissipation area for each servo amplifier when the servo amplifier is operated 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 enclosure will be steeper.

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