DM870 Digital Stepping Driver Manual V1.0
Tel: +086 0755-26434369 7 Web Site: www.leadshine.com
Connections to 8-lead Motors
8 lead motors offer a high degree of flexibility to the system designer in that they may be connected
in series or parallel, thus satisfying a wide range of applications.
Series Connections
A series motor configuration would typically be used in applications where a higher torque at lower
speeds is required. Because this configuration has the most inductance, the performance will start to
degrade at higher speeds. In series mode, the motors should also be run at only 70% of their rated
current to prevent over heating.
Figure 7: 8-lead motor series connections
Parallel Connections
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
NEVER
disconnect or connect the motor while the power source is energized.
6. Power Supply Selection
The DM870 can match medium and small size stepping motors (from NEMA frame size 17 to 34)
made by Leadshine or other motor manufactures around the world. To achieve 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
DM870 Digital Stepping Driver Manual V1.0
Tel: +086 0755-26434369 8 Web Site: www.leadshine.com
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.
Note: MEANWELL
DRP-240-24(24VDC, 240Watt power supply) must be selected in order
to make the whole system comply with UL standards for safety.
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. If regulated
power supplies (such as most switching supplies.) are indeed used, it is important to have large
current output rating to avoid problems like current clamp, for example using 4A supply for 3A
motor-Drive operation. 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.
Multiple Drives
It is recommended to have multiple Drives to share one power supply to reduce cost, if the supply
has enough capacity. To avoid cross interference,
DO NOT
daisy-chain the power supply input pins
of the Drives. Instead, please connect them to power supply separately.
Selecting Supply Voltage
The power MOSFETS inside the DM870 can actually operate within +24 ~ +80VDC, including
power input fluctuation and back EMF voltage generated by motor coils during motor shaft
deceleration. Higher supply voltage can increase motor torque at higher speeds, thus helpful for
avoiding losing steps. However, higher voltage may cause bigger motor vibration at lower speed, and
it may also cause over-voltage protection or even Drive damage. Therefore, it is suggested to choose
only sufficiently high supply voltage for intended applications, and it is suggested to use power
supplies with theoretical output voltage of +24 ~ +72VDC, leaving room for power fluctuation and
back-EMF.