Calculation Method Of Heat Amount Generated By The Programmable Controller - Mitsubishi Electric MELCEC Q Series User Manual

9. LOADING AND INSTALLATION
9.4

Calculation Method of Heat Amount Generated by the Programmable Controller

It is necessary to keep the temperature of the panel which stores the programmable
controller to the operating ambient temperature of the programmable controller, which is
55
average power consumption (heat generation) of the devices and machinery stored inside.
In this section, a method to obtain the average power consumption of the programmable
controller system is explained. Calculate the temperature rise inside the panel from the
power consumption.
(Calculation method of average power consumption)
The power consuming parts of the programmable controller may be roughly classified into
the blocks as shown below:
(1)
(2)
, or below. For heat dissipation design of the panel, it is necessary to know the
Power consumption by power supply module
The power conversion efficiency of the power supply module is about 70%, and 30%
is consumed as heat generated, thus, 3/7 of the output power is the power
consumption. Therefore, the calculation formula is:
3
Wpw= {(I 5) + (I
5V 15V
7
I : Current consumption of 5VDC logic circuit of each module
5V
I : Current consumption of 15VDC external power supply part of special function
15V
module
I : Average current consumption of 24VDC power supply for internal consumption
24V
of the output module
(Current consumption equivalent to the points simultaneously ON)
Not applicable to a system where 24VDC is supplied externally and a power
supply module which does not have a 24VDC output is used.
Total power consumption of each module at 5VDC logic part
Power of the 5VDC output circuit of the power supply module is the power
consumption of each module.
W =I 5(W)
5V 5V
15) + (I 24)}(W)
24V
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