Mitsubishi Electric A173UHCPU User Manual page 90

2. DESIGN
If the enclosure temperature rises above the prescribed range, a heat exchanger should be
attached to the enclosure to lower the temperature.
Ventilation of the enclosure with a fan can result in dust problems with the motion controller
because of the dust which is introduced with the ambient air.
(4) Average power consumption from voltage drop in output circuits of the output
modules (power consumption of simultaneously ON points)
= I
W Vdrop No. output points Simultaneously ON ratio (W)
OUT OUT
I : I is the output current(actual operation current) (A)
OUT OUT
Vdrop: Vdrop is the voltage drop of each output module (V)
(5) Average power consumption from voltage drop in input circuits of the input
modules (power consumption of simultaneously ON points)
= I
W E No. input points Simultaneously ON ratio (W)
IN IN
I : I is the input current (effective value for AC) (A)
IN IN
E : E is the input voltage (actual operation voltage) (V)
(6) Power consumption of special-function module power supply circuits
W = I 5 + I
S 5V 24V
The total power consumption of each block described above is the power
consumption of the entire PC system.
W = W + W + W
PW 5V
Use the overall calculated power consumption (W) to calculate the heat
generation and temperature rise inside the enclosure.
The following equation approximately calculates the temperature rise in the
enclosure:
W
T = ( C)
UA
W : W is the overall power consumption of the motion controller (calculated
above)
A : internal surface area of the enclosure (m
U : if a fan is used to make enclosure temperature uniform ............6
if air is not circulated inside the enclosure ..................................4
24 I v 100(W)
100
+ W + W + W
24V OUT IN
CAUTION
2 − 21
(W)
S
2
)