Specifications

Brushless Technology
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Some common BLDC advantages include:
n Ability to control motors over a wide range
of speeds
n Precise speed regulation without additional cost
n Rapid acceleration and deceleration capability
n Starting torque and dynamic response equal to or
better than conventional DC drives
n Ability to operate several brushless drives from a
common DC bus
n No mechanical wear or conductive brush dust
from brushes
Electronic commutation in brushless drives eradicates the
need for brushes in the motor, and therefore all associat-
ed maintenance. Minarik brushless drives use hall-effect
sensors located within the motor to determine the rotor
position for proper commutation and determination of
which power transistors to turn ON to obtain maximum
motor torque. Since commutation now becomes electri-
cal, only motor bearings suffer from mechanical wear.
BLDC motors run at higher speeds than PM DC motors
because the frictional components of mechanical com-
mutation do not limit their speed and higher efficiencies
can be achieved at higher speeds. BLDC motors provide
more reliable performance since environmental issues
such as humidity or elevation do not play a part in the
now non-existent brushes, brush film, voltage drops, and
mechanical wear. If properly sized, and properly pack-
aged, your next BLDC motor could handle all your motion
control needs AND last you a lifetime.
Cut-away view of a conventional
permanent-magnet DC motor assembly.
Cut-away view of a brushless DC
motor assembly.
Permanent Magnet
Stator
Rotor
rushless DC (BLDC) systems combine the positive
attributes of AC and DC systems. As a result, their
usage in new applications continues to grow. Permanent
magnet (PM) designs are the most popular brush type DC
motors sold on the market today. They employ permanent
magnets on the stator which in turn react with wound elec-
tromagnets on the rotor. These DC motors incorporate car-
bon brushes which slide over and transmit electrical power
to the commutator which in turn switches power to the rotor
windings to provide smooth rotation. Benefits of this design
include a linear speed-torque performance which is easily
controlled, a small motor diameter, predictable torque
throughout a wide speed range, high starting torque, and
minimal wiring.
Depending on the application these self commutating
motors may cause electrical noise and are susceptible to
brush and commutator maintenance or a finite life
expectancy. Users who cannot tolerate this motor mainte-
nance have sometimes opted for AC motors which are
brushless, small, and inexpensive. However, AC systems
have typically been limited by a narrow speed range, poor
torque output at low speeds, and large expensive drives.
Minarik has now introduced our AC variable frequency
MAC drive to combat these very issues and control these
AC motors in a cost effective package.
BLDC motors also address several of the pitfalls of the DC
Brush motor, while maintaining the advantages of perma-
nent magnet DC motor performance. BLDC motors are
similar to permanent magnet AC synchronous motors with
a magnetic rotor and wound stator construction. BLDC
wound stators can rapidly dissipate heat to the housing and
environment in contrast to PM brush motors which trap the
heat under a non-conductive air gap. This results in greater
efficiency and power density for
the BLDC design and provides
high torque-to-inertia ratios.
Permanent Magnet
Rotor
Stator
B
Call us toll free 1•800•MINARIK or download manuals at www.minarikdrives.com
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BRUSHLESS DC DRIVES