Calculating Heat Generation By Motion Controller - Mitsubishi Q172CPU User Manual

3 DESIGN

3.3.3 Calculating heat generation by Motion controller

The ambient temperature inside the control panel storing the Motion controller must be
suppressed to a Motion controller operating ambient temperature of 55°C(131°F).
It is possible to remove the Cooling fan unit(Q170FAN) depending on the number of
CPU modules or operating ambient temperature conditions.(Refer to section 2.4.11
Cooling fan unit (Q170FAN).)
For the design of radiation from the storing panel, it is necessary to know the average
power consumption (heating value) of the devices and instruments stored in the control
panel. Here the method of obtaining the average power consumption of Q173CPU(N)/
Q172CPU(N) system is described. From the power consumption, calculate a rise in
ambient temperature inside the control panel.
Calculating average power consumption
The power consuming parts of the Motion controller are roughly classified into six
blocks as shown below.
(1) Power consumption of the power supply module
The power conversion efficiency of the power module is approx. 70 [%], i.e., 30
[%] of the output power is consumed by heating. As a result, 3/7 of the output
power becomes the power consumption.
Therefore the calculation formula is as follows.
3
Wpw= (I
5V
7
I : Current consumption of logic 5 VDC circuit of each module
5V
(2) Power consumption of a total of 5 VDC logic section of each
module
The power consumption of the 5 VDC output circuit section of the power module
is the power consumption of each module (including the current consumption of
the base unit).
W = I 5 [W]
5V 5V
(3) A total of 24 VDC average power consumption of the output module
(power consumption for simultaneous ON points)
The average power of the external 24 VDC power is the total power consumption
of each module.
W = I 24 [W]
24V 24V
I
: Current consumption of the output module
24V
(4) Average power consumption due to voltage drop in the output
section of the output module
(Power consumption for simultaneous ON points)
W = I Vdrop
OUT OUT
I : Output current (Current in actual use) [A]
OUT
Vdrop : Voltage drop in each output module [V]
(5) Average power consumption of the input section of the input
module(Power consumption for simultaneous ON points)
W = I E
IN IN
I : Input current (Effective value for AC) [A]
IN
E : Input voltage (Voltage in actual use) [V]
5)[W]
Number of output points
Number of input points
3 - 17
Simultaneous ON rate [W]
Simultaneous ON rate [W]