Applied Motion STR4 - Manual (Page 42)

42
STR4/8 Hardware Manual 920-0030J
5/12/2015
Drive Heating
While STR drivers efficiently transmit power between the power supply and motor, they do
generate some heat in the process. This will cause the temperature of the drive to rise above
the surrounding air temperature and may also require that the drive be mounted to a heat
conducting metal surface.
For those who wish to calculate the power dissipation and temperature rise, the following infor-
mation is provided:
1. drive power dissipation P
d
versus motor current and power supply voltage (see chart)
2. 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 13.5” x 13.5” steel plate, .070” thick: R
Q
=1.0°C/W
Narrow side of drive mounted on a non-heat conducting surface: R
Q
=2.1°C/W
15
20
25
Lo
ss
(W
)
STR Drive Losses
60V
48V
24V
0
5
10
1 2 3 4 5 6 7 8
D
ri
ve
r
motor current (A)