June 2019
L011804
Step Motor Confi gurations
Step motors can be con
fi
gured as 4, 6 or 8 leads. Each con
fi
guration requires different currents. Refer
to the lead con
fi
gurations and the procedures to determine their output current.
Determining Output Current
The output current for a motor used with a bipolar driver is determined differently from that of a unipolar
driver. In the MBC25081-06, a sine/cosine output function is used in rotating the motor. The output cur-
rent for a given motor is determined by the motors current rating and the wiring con
fi
guration of the motor.
There is a current adjustment potentiometer used to set the output current of the MBC25081-06. This
sets the peak output current of the sine/cosine waves. The speci
fi
ed motor current (which is the unipolar
value) is multiplied by a factor of 1.0, 1.4, or 2.0 depending on the motor con
fi
guration (series, half-coil,
or parallel).
6 Lead Motors
Half-Coil Connection:
When con
fi
guring a 6 lead motor in half-coil (connected from one end of the coil
to the center tap), multiply the speci
fi
ed per Phase (or unipolar) current rating by 1.4 to determine the
current setting potentiometer value. This con
fi
guration will provide more torque at higher speeds when
compared to the series con
fi
guration.
Series:
When con
fi
guring the motor is series (connected from end to end with the center tap
fl
oating) use
8 Lead Motors
Series Connection:
When con
fi
guring the motor windings in series, use the per Phase (or unipolar) cur-
rent rating to determine the current setting potentiometer value.
Parallel Connection:
When con
fi
guring the motor windings in parallel, multiply the per Phase (or unipolar)
current rating by 2.0 to determine the current setting potentiometer value.
4 Lead Motors
Series Connection:
Multiply the speci
fi
ed series motor current by 1.4 to determine the current adjustment
potentiometer value. Four Lead Motors are usually rated with their appropriate series current, as opposed
to the
Phase Current,
which is the rating for 6 and 8 lead motors.
July 2018
