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DMA860E Digital Stepper Drive User Manual
Because this configuration has the most inductance, the performance will start to degrade at higher speed. In series
mode, the motors should also be run at only 70% of their rated current to prevent overheating.
Figure 7: 8-lead motor series connections
5.3.2 Parallel Connection
An 8 lead motor in a parallel configuration offers a more stable, but lower torque at lower speeds. But because of the
lower inductance, there will be higher torque at higher speeds. Multiply the per-phase (or unipolar) current rating by
1.96, or the bipolar current rating by 1.4, to determine the peak output current.
Figure 8: 8-lead motor parallel connections
6. Power Supply Selection
The DMA860E can power medium and large size stepping motors (frame size from NEMA 23 to 42) made by
Leadshine or other motor manufacturers. To get good driving performances, it is important to select supply voltage and
output current properly. Generally speaking, supply voltage determines the high speed performance of the motor, while
output current determines the output torque of the driven motor (particularly at lower speed). Higher supply voltage
will allow higher motor speed to be achieved, at the price of more noise and heating. If the motion speed requirement is
low, it's better to use lower supply voltage to decrease noise, heating and improve reliability.
6.1 Regulated or Unregulated Power Supply
Both regulated and unregulated power supplies can be used to supply the drive. However, unregulated power supplies
are preferred due to their ability to withstand current surge and fast response for current change. If you prefer to a
regulated power supply, it is suggested to choose such a power supply specially designed for stepper/servo controls
such as Leadshine RPS series (http://www.leadshine.com/producttypes.aspx?producttype=regulated-switching). Or, in
the case when only normal switching power supplies are available, it is important to use "OVERSIZE" high current
output rating power supplies (for example, using a 4A power supply for 3A stepper motor) to avoid problems such as
current clamp. On the other hand, if unregulated supply is used, one may use a power supply of lower current rating
than that of motor (typically 50%～70% of motor current). The reason is that the drive draws current from the power
supply capacitor of the unregulated supply only during the ON duration of the PWM cycle, but not during the OFF
duration. Therefore, the average current withdrawn from power supply is considerably less than motor current. For
example, two 3A motors can be well supplied by one power supply of 4A rating.
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