DM556T Digital Stepper Drive User Manual
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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 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 DM556T can power medium and small size stepping motors (frame size from NEMA23 to 34) made by
STEPPERONLINE 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. 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Therefore, the average current withdrawn from power supply is considerably less than motor current.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.
6.2 Power Supply Sharing
Multiple DM556T drives can share one power supply to reduce cost, if that power supply has enough power capacity.
To avoid cross interference, connect each stepper drive directly to the shared power supply separately. To avoid cross
interference, DO NOT daisy-chain connect the power supply input pins of the Drivers. Instead connect them to power
supply separately.
6.3 Selecting Supply Voltage
The DM556T is designed to operate within +20 - +50VDC voltage input. When selecting a power supply, besides
voltage from the power supply power line voltage fluctuation and back EMF voltage generated during motor
deceleration needs also to be taken into account. Ideally it is suggested to use a power supply with the output range
