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2
5.3 Connection to 4-Lead Motors
4 lead motors are the least flexible but easiest to wire. Speed and torque will depend on winding
inductance. In setting the driver output current, multiply the specified phase current by 1.4 to
determine the peak output current.
Figure 8: 4 Lead Motor Connections
6. Power supply Selection, Driver Voltage and Current
Selection
6.1 Power Supply Selection
It is important to choose appropriate power supply to make the driver operate properly and
deliver optimal performance.
Maximum Voltage Input:
The power MOSFETS inside the driver can actually operate within +24V
+90VDC,
including power input fluctuation and back EMF voltage generated by motor coils during
motor shaft deceleration. Higher voltage will damage the driver. Therefore, it is suggested to
use power supplies with theoretical output voltage of no more than +95V, leaving room for
power line fluctuation and back-EMF.
Regulated or Unregulated power supply:
Both regulated and unregulated power supplies can be used to supply DC power to the driver.
However, unregulated power supplies are preferred due to their ability to withstand current
surge. If regulated power supply (such as most switching supplies.) is 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 the ON duration of the PWM cycle, but not
during 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 Therefore, the average current withdrawn from power supply is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 drivers:
It is recommended to have multiple drivers to share one power supply to reduce cost, provided
that the supply has enough capacity. To avoid cross interference, DO NOT daisy-chain the
power supply input pin of the drivers (connect them to power supply separately).
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.
Attention: NEVER connect power and ground in the wrong direction, as it will damage the
driver.
6.2 Driver Voltage and Current Selection
This driver can match small and medium size step motors (NEMA 34 and 43) made by Leadshine
or other motor manufactures from around the world. To achieve good driving results, it is
important to select supply voltage and output current properly. Generally, 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).
●
Selecting Supply Voltage:
Higher supply voltage can increase motor torque at higher speeds, thus helpful for avoiding losing
steps. However, higher voltage may cause more motor vibration at lower speed, and it may also
cause over-voltage protection and even driver damage. Therefore, it is suggested to choose only
sufficiently high supply voltage for intended applications.
●
Setting Proper Output Current
a. For a given motor, higher driver current will make the motor to output more torque, but at the
same time causes more heating in the motor and driver. Therefore, output current is generally
set to be such that the motor will not overheat for long time operation.
b. Since parallel and serial connections of motor coils will significantly change resulting
inductance and resistance, it is therefore important to set driver output current depending on
motor phase current, motor leads and connection methods.
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