MA860C Full Digital Stepper Drive Manual V1.0
4.5 Power Supply Selection
The MA860C can match medium and small size stepping motors (frame size from NEMA24 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 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.
4.5.1 Regulated or Unregulated Power Supply
Both AC (18~80VAC)and DC (30~100VDC)power supplies can be used to supply the drive. However, AC power are
preferred due to it can provide more power and higher torque to the motor under the same cost. But if the AC mains
supply fluctuates greatly, it’s better to connect an AC voltage stabilizer between AC power and transformer. It’s also
can use DC power supplies include regulated power supplies (such as most switching supplies.) and unregulated power
supplies. When using regulated power supplies, 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 Therefore, the average current withdrawn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.
4.5.2 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.)
4.5.3 Selecting Supply Voltage
The power MOSFETS inside the MA860C can actually operate 30-100VDC, 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 36~70VAC or 50~90VDC, leaving room for power fluctuation and
back-EMF.
4.6 Wiring Notes
In order to improve anti-interference performance of the drive, it is recommended to use twisted pair shield cable.
To prevent noise incurred in PUL/DIR signal, pulse/direction signal wires and motor wires should not be tied up
together. It is better to separate them by at least 10 cm, otherwise the disturbing signals generated by motor will
easily disturb pulse direction signals, causing motor position error, system instability and other failures.
If a power supply serves several drives, separately connecting the drives is recommended instead of
daisy-chaining.