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Difference Between Brushed DC Motor and Brushless DC Motor

Electric motors are used in almost every industry and in a wide range of applications. Electric motors are available in a wide range of sizes and types. DC Motors can be selected based on their Speed, torque, cost and many more, and applications. Using the proper motor with high-quality parts and performing regular maintenance keeps your motor running smoothly and protects endpoint equipment from wear and power spikes.

This article discusses the major differences between the Brushed DC Motor and Brushless DC Motor which helps you to choose the exact motor for your applications. 

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What is a Brushed DC Motor?

Brushed DC motors are one of the simplest types of DC motor. It usually consists of a stator (a pair of permanent magnets) and a rotor (a motor coil) coupled to a commutator. The armature winding is on the rotor, and permanent magnets are always on the stator with this motor. Current-carrying conductors are always found on the rotating portion. These wires are powered by a direct current power source in practice. The electricity is transferred to the coil by metallic brushes that rotate with the rotor. Although these motors are highly efficient, they do require brush cleaning on a regular basis.

Instead of using a controller to switch current in the windings, brushed motors use mechanical commutation of the windings via brushes. Brushes charge the commutator with a polarity opposite that of the fixed magnet, causing the armature to rotate. When these windings become charged, they generate a magnetic field whose attraction and repulsion keep the rotor spinning. The windings are constantly energized in a varied sequence as the rotor rotates within the stator field to maintain the rotor moving.

Brushes installed inside electric motors employ commutator contacts to deliver current to the motor windings.

What is a Brushless DC Motor?

Brushless DC electric motors also known as electronically commutated motors (ECMs, EC motors). A Brushless DC Motor is similar to a Brushed DC Motor but as the name suggests, a BLDC doesn’t use brushes for commutation but rather they are electronically commutated.  Brushes are utilized to deliver power to the rotor in traditional Brushed DC Motors as they turn in a fixed magnetic field.

The rotor of a brushless DC motor is made up of permanent magnets, and the stator is made up of polyphase armature windings. It differs from the conventional dc motor in such that it doesn’t contain brushes and the commutation is done electrically, using an electronic drive to feed the stator windings. These types of motors are highly efficient in producing a large amount of torque over a vast speed range.These motors are highly effective at providing a lot of torque across a wide speed range. They’re known for their quiet operation and the ability to hold torque when stationary.

Difference between Brushed DC Motor and Brushless DC Motor

ParametersBrushed DC motorBrushless DC motor
CommutationIt uses brushes to deliver current to the motor windings through mechanical commutationIt uses Electrical commutation to deliver the current.
Speed RangeLower compared to BLDCHigh- because of the absence of brushes and commutator
ControlSimpleComplex and expensive
Electrical noiseArcs in the brushes generate noiseLow
Rotor inertiaHigher rotor inertia which limits dynamic characteristicsLow, because it has permanent magnets on the rotor. it increases dynamic response
MaintenancePeriodic maintenance requiredLess required in absence of brushes
speed/torque characteristicsLow-mechanical limitation by brushesHigher-no mechanical limitations
EfficiencyIt is less efficient because of power losses.It is more efficient
LifeShort LifeLong Life
GearingIt requires gearing as it runs very fast.No need for gearing
Building costLower compare to BLDCHigher- since it has permanent magnets
Control requirementNo controller is requiredController is always required to keep motor running
ConstructionArmature winding is on rotar; Fixed magnets are placed on either side of the rotating electromagnetArmature winding is on stator and fixed magnets are on rotar
ApplicationsHome appliances, kid toys, in industrial applications, medical equipments, robots and drones to electric cars, power tools etcElectric vehicles, hybrid vehicles, and electric bicycles, Industrial applications, drones, washing machines, Fans, pumps and blowers etc

What are the Advantages of Brushed and Brushless DC Motors?

Advantages

Brushed

  • Low overall construction costs;
  • Can often be rebuilt to extend life;
  • Simple and inexpensive controller;
  • Controller not needed for fixed speed;
  • Ideal for extreme operating environments.

Brushless

  • Less overall maintenance due to lack of brushes;
  • Operates effectively at all speeds with rated load;
  • High efficiency and high output power to size ratio;
  • Reduced size with far superior thermal characteristics;
  • Higher speed range and lower electric noise generation.

Disadvantages

Brushed 

  • Periodic maintenance is required.
  • Less efficient.
  • Electrically noisy.
  • Poor heat dissipation due to internal rotor construction.
  • Higher rotor inertia limits the dynamic characteristics.
  • Speed/torque is moderately flat. At higher speed brush friction increases thus reducing useful torque.
  • Lower speed range due to mechanical limitation s on the brushes.
  • Brush arcing will generate noise-causing electrical magnetic interference.

Brushless Motor

  • These motors are costly
  • Electronic controller required control this motor is expensive
  • Not much availability of many integrated electronic control solutions, especially for tiny BLDC motors
  • Requires complex drive circuitry
  • Need of additional sensors

Hope this blog helps you to understand about the difference between a brushed dc motor and brush-less Dc motor. We ,MATHA ELECTRONICS will be back with more informative blogs.

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