Applied Motion SWM24IP-3EE - Manual (Page 32)

Drive/Motor Heating
Step motors convert electrical power from the driver into mechanical power to move a load. Because step motors are
not perfectly efficient, some of the electrical power turns into heat on its way through the motor. This heating is not so
much dependent on the load being driven but rather the motor speed and power supply voltage. There are certain
combinations of speed and voltage at which a motor cannot be continuously operated without damage.
We have characterized the SWM24 in our lab and provided curves showing the maximum duty cycle versus speed for
commonly used power supply voltages. Please refer to these curves when planning your application.
Please also keep in mind that a step motor typically reaches maximum temperature after 30 to 45 minutes of operation.
If you run the motor for one minute then let it sit idle for one minute, that is a 50% duty cycle. Five minutes on and five
minutes off is also 50% duty. However, one hour on and one hour off has the effect of 100% duty because during the
first hour the motor will reach full (and possibly excessive) temperature.
The actual temperature of the motor depends on how much heat is conducted, convected or radiated out of it. Our
measurements were made in a 40°C (104°F) environment with the motor mounted to an aluminum plate sized to provide
a surface area consistent with the motor power dissipation. Your results may vary.
SWM24X-3 Max Duty Cycle vs Speed
6A/phase, 40°C Ambient
Mounted on a 162 x 162 x 6 (mm)
Aluminum Plate
0
20
40
60
80
100
0 10 20 30 40 50
Speed (RPS)
e l c
y C
y t
u D
%
12V Duty Cy c le
24V Duty Cy c le
48V Duty Cy c le
65V Duty Cy c le
32
SWM24 Hardware Manual
920-0068B
10/31/2013