Brushless DC Motor

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Brushless DC electric motor (BLDC motorsBL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors  that are powered by a DC electric source.

The rotor part of a brushless motor is often a permanent magnet synchronous motor  but can also be a  induction motor .


Brushless motors may be described as stepper motor, however, the term stepper motor tends to be used for motors that are designed specifically to be operated in a mode where they are frequently stopped with the rotor in a defined angular position.

Brushless motors  have the armature winding having which is stationary and the permanent magnet at the inside the  yoke part of motor which rotates along with shaft but the armature winding is stationary.

Brushed DC motors develop a maximum torque  when stationary, linearly decreasing as velocity increases. Some limitations of brushed motors can be overcome by brushless motors; they include higher efficiency and a lower susceptibility to mechanical wear. These benefits come at the cost of potentially less rugged, more complex, and more expensive control electronics.


A typical brushless motor has permanent magnets which rotate and a fixed armature , eliminating problems associated with connecting current to the moving armature.

Brushless motors offer several advantages over brushed DC motors, including more torque per weight, more torque per watt (increased efficiency), increased reliability, reduced noise, longer lifetime (no brush and commutator erosion), elimination of ionizing sparks from the commutator, and overall reduction of electromagnetic interference (EMI). With no windings on the rotor, they are not subjected to centrifugal forces, and because the windings are supported by the housing, they can be cooled by conduction, requiring no airflow inside the motor for cooling. This in turn means that the motor’s internals can be entirely enclosed and protected from dirt or other foreign matter.

Brushless motor commutation can be implemented in software using a microcontroller or microprocessor computer, or may alternatively be implemented in analogue hardware.


The maximum power that can be applied to a brushless motor is limited almost exclusively by heat;too much heat weakens the magnet and may damage the winding’s insulation.

When converting electricity into mechanical power, brushless motors are more efficient than brushed motors. This improvement is largely due to the brushless motor’s velocity being determined by the frequency at which the electricity is switched, not the voltage.



Heating and ventilations- HVAC and refrigeration.

Industrial Engineering:-

                      Motion control systems

                      Positioning and actuation systems

Model Engineering:-

In air craft ,Helicopter,Quard copter.

Radio Controlled Cars.


2 thoughts on “Brushless DC Motor

  1. Pingback: How To: Reduce Stepper Motor Heating up |

    • Reduce heating, is to reduce the copper loss and iron loss. There are two ways to reduce the copper loss, reduce resistance and current, that require to choose low resistance and low rated current motor. It’s no good ways to reduce the iron loss, it’s related with the voltage levels. High voltage will bring high speed, but it also increase heat.

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