Mitsubishi Electric Melservo-J4 MR-J4-DU*B4-RJ100 Series Instruction Manual page 59

Heat dissipation area for an enclosed type cabinet
The enclosed type cabinet (hereafter called the cabinet) which will contain the power regeneration converter unit and drive
unit should be designed to ensure that its temperature rise is within +10  at the ambient temperature of 40 . Calculate the
necessary cabinet dissipation area (allowing a margin of approximately 5  for the ambient temperature of 55  maximum)
with the following equation.
P
A =
K•∆T
2
A: Heat dissipation area [m ]
P: Loss generated in the cabinet [W]
∆T: Difference between internal and ambient temperatures []
K: Heat dissipation coefficient [5 to 6]
When calculating the heat dissipation area with the equation, assume that P is the sum of all losses generated in the cabinet.
Refer to the following for the generated heat of the power regeneration converter unit and drive unit.
Page 56 Generated heat of the power regeneration converter unit and drive unit
"A" indicates the effective area for heat dissipation, but if the cabinet is directly installed on an insulated wall, that extra
amount must be added to the cabinet's surface area. The required heat dissipation area will vary with the conditions in the
cabinet. If convection in the cabinet is poor and heat builds up, effective heat dissipation will not be possible. Therefore,
arrangement of the equipment in the cabinet and the use of a cooling fan should be considered. The following lists the cabinet
dissipation area (guideline) when the converter unit and drive unit are operated at the ambient temperature of 40  under
rated load.
Page 56 Generated heat of the power regeneration converter unit and drive unit
When air flows along the outer wall of the cabinet, effective heat exchange will be possible, because the temperature slope
inside and outside the cabinet will be steeper.
(Outside the cabinet)
(Inside the cabinet)
Air flow
7 CHARACTERISTICS
7.2 Power supply capacity and generated loss
7
57