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NI SMD-7613/7614/7615/7616 User Manual
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© National Instruments
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47
To calculate the power dissipation and temperature rise, the following information is provided.
Given:
drive power dissipation P
d
versus motor (refer to the figures below)
drive thermal constant R
Q
The final drive case temperature is given by:
T
C
= T
a
+ R
Q
* P
d
where T
a
is the ambient temperature of the surrounding air. The case of the drive should not be
allowed to exceed 70 °C or the life of the product could be reduced.
Drive thermal constant:
Narrow side of drive mounted on a 3.5” × 13.5” steel plate, 0.070 in. thick: R
θ
= 1.0 °C/W
Narrow side of drive mounted on a non-heat conducting surface: R
θ
= 2.1 °C/W
Figure 70.
Drive Thermal Losses
S
MD-7611/7612 Drive Lo
ss
e
s
Motor C
u
rrent (A)
Dr
iv
er Lo
ss
(W)
0
5
10
15
20
25
1
2
3
4
5
6
7
8
60V
24V
48V