MC556 High Performance Microstepping Driver
MC556 High Performance Microstepping Driver
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5. Connecting the Motor
The M556 can drive any 2-pahse and 4-pahse hybrid stepping motors.
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Connections 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 6: 4-lead Motor Connections
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Connections to 8-lead Motors
8 lead motors offer a high degree of flexibility to the system designer in that they may be
connected in series or parallel, thus satisfying a wide range of applications.
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Series Connections
A series motor configuration would typically be used in applications where a higher
torque at lower speeds is required. Because this configuration has the most inductance, the
performance will start to degrade at higher speeds. In series mode, the motors should also
be run at only 70% of their rated current to prevent over heating.
Figure 7: 8-lead motor series connections
6. Power Supply Selection
The MC556 can match medium and small size stepping motors (from NEMA frame size
17 to 34) made by Lichuan 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.
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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 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.