Hardware
Installation Manual of Easy Servo
15
HWMN-ES-R20130312
Power Supply Selection
To achieve good driving performances, it is important to choose a suitable supply voltage and use a
matching current value. 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 drive. 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withdrawn from power supply is considerably less than motor current.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
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 drive
’
s m 10% to drive
’
s maximum
–
10%, leaving room
for power fluctuation and back-EMF.
