Power Supply Selection; Regulated Or Unregulated Power Supply - SUNWIND M542H User Manual

Sunwind Electronics Company Ltd.
Stepper Motor Driver:M542H
Figure 9: 8-lead motor parallel connections

6. Power supply Selection

The M542H can match medium and small size stepping motors (from Nema size 17 to 34) made by
Sunwind 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.

Regulated or Unregulated Power Supply

Both regulated and unregulated power supplies can be used to supply the driver. 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-driver 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 driver draws current from the power
supply capacitor of the unregulated supply only during theON duration of the PWM cycle, but not during
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