34
CENTENT CN0162 MICROSTEP DRIVE
FULL STEPS PER SECOND
10K
20K
0
0.5A
1.0A
1.5A
PO
WE
R SUPPL
Y
C
URR
EN
T
Figure 14: Power supply current
MOTOR AND DRIVE HEATING
Motor and drive heating is equivalent to the difference between the electrical power
input and the motor's mechanical power output. The ratio of output power to input
power is the system efficiency.
The power losses are dependent on motor speed, load and winding configuration, the
power supply voltage, current set and other factors. The power losses in a step motor
drive are primarily resistive and therefore easy to calculate. Each channel of the drive
may be considered to be equivalent to a .55 ohm resistor.
Step motor drive current dissipation in Region 1 is always considerably higher than in
Region 2. In Region 1, motor phase currents, and therefore drive channel currents are
sinusoidal. The peak amplitude is equal to the rated per phase current in the
half-winding mode and half of that in the full-winding mode. In Region 1, power
dissipation may be calculated as follows.
