Power Supply Connection; Regulated Or Unregulated Power Supply - Motion DMD870 User Manual

DMD870 Digital Stepper Drive User's Manual
Figure 7: 8-lead motor parallel connections
NEVER disconnect or connect the motor while the power source is energised.

6. POWER SUPPLY CONNECTION

The DMD870 can match medium and small size stepping motors (from frame size NEMA 17
to size NEMA 34) made by MCP 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 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.
MEANWELL
Note: 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 Therefore, the average current withdrawn from power supply is
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