abstract:Power instruments, including brushless and brushed DC motors, are very important devices in our dail...
Power instruments, including brushless and brushed DC motors, are very important devices in our daily lives for making difficult tasks into simple and easy ones with higher productivity. It is very necessary to know the difference between brushless and brushed DC motors to have a better understanding of their performances. When comparing brushless and brushed motors is important, the selection and choice between those two DC motors rely on criteria such as efficiency, life span, cost, etc.
Brushless and brushed DC motors are perfect for each specific and different type of application. To have a better understanding of their uses, it is always important to have ideas regarding the differences between them. There are some important factors of differences between brushed and brushless motors that help users select the right one for better applications. Those factors have been discussed in detail below.
Important factors for the difference between brushed and brushless DC Motor:
#1. Better Efficiency
Brushless motors have higher efficiency than brushed motors. Brushless motors transform electrical power to mechanical power with improved accuracy which minimizes energy waste. There are no friction and energy waste related with brushes and commutators in brushless DC motor. It provides higher performance, extended run time and lower energy consumption.
On the other hand, because of power losses caused by friction and power transmission by commutator system, brushed motors are known as less efficient than brushless DC motor.
#2. Maintenance and Longevity
Brushless motors contain less moving parts without any mechanical connection that provides extended life-time and lowered maintenance needs. The lack of brushes in brushless motors removes the trouble of brush wear and other maintenance matters. Thus, brushless motor turns out to be a cost-effective preference for users.
Alternatively, brushed motors need additional maintenance because of the wear and tear on brushes and commutators that causes the reduction in performance and motor deficiency. Brush substitutes are required frequently to preserve maximum performance.
#3. Noise and Vibration
In a brushless motor, it is attainable to regulate the winding currents. Regulating the winding currents minimizes torque ripple that creates vibration and mechanical noise. Brushless motors generally create little noise and vibration in comparison to brushed motors due to lacking of brushes or commutators. Because of little vibration and noise, brushless motors increase the convenience for the users and minimize wear for the long period of use.
In brushed DC motor, brushes and commutator make a switch together. When the motor runs, the switches start being opened and closed. During this time, high current flows through the rotor windings that are inductive type. Due to the high flow of current, it creates huge electrical noise. For the avoidance of electrical noise, BLDC motors are better choices than brushed motors.
#4. Cost and Complexity
Because of the electronic control systems for commutation, brushless motors are usually more costly and sophisticated. The benefits of brushless motors, such as efficiency, lifespan and maintenance, exceed the primary cost difference. The price of a brushless dc motor is higher than that of brushed DC motor because of the presence of complicated electronics technology in brushless DC motor.
#5. Design and Operation
Brushless DC motors are not self-commutated. They need a drive circuit that use transistors to regulate the current through winding coils of the motor. Electronic control and hall-effect sensors are used in brushless motors to regulate the flow of current in the windings without using mechanical connection. Driver circuit is used to observe the feedback from the motor and transistors are used to make active the stator poles so that the rotor can be rotated. The feedback is used in brushless motor to control the speed of the motor. Brushed motor does not have any feedback. The rotor, stator, and the hall-effect IC of the brushless motor are mentioned in the following figure.
Brushed DC motors are self-commutated DC motors and those don’t need a drive circuit to be operated. Mechanical brushes and a commutator are used to regulate the flow of current in the windings that creates a magnetic field. Due to the generation of magnetic field, torque is produced and the motor is rotated.
#6. Speed or Torque Characteristics
Brushless motors can be regulated at its highest rotational torque in a continuous way. The speed-torque relationship can be controlled in brushless DC motor for its excellent performance. Thus, brushless DC motors perform always the same.
On the other hand, brushed motors can achieve maximum torque only at some fixed points during the rotation. Larger magnets are needed for brushed motor to create the same torque as brushless motors. Brushed motors need a gearing system to lower the speed while increasing torque. Brushed motors need to run fast to make them essential for the most uses. Substantial amount of power (physics) can be provided by small BLDC motors.
Sparks can be produced by brushed motors. Thus, brushed motors can be the cause of explosion. In this regard, brushless motors are more favorite options than brushed motor.
#8. Electrical consumption
Due to excellent electrical consumption feature, many tools use brushless motor for getting high efficiency. The current supply can be automatically regulated in brushless DC motor.
Since the price of brushless motor and its associated electronics are getting decreased day by day, the demand of brushless motor is getting higher than that of brushed motors. Brushless motors are very popular for electric vehicles, hybrid vehicles, electric bicycles, drones, washing machines, fans, pumps, and blowers, etc. The application of brushless motor is significant in automobiles for its excellent reliability.
The electronics technology in brushless motor makes the rate of failures low and reduced maintenance requirements. Better efficiency, less electric noise generation, being faster, etc. have made brushless motors a better choice compared to the brushed ones. Due to declining costs and better performance, brushless motors are gaining in popularity in many applications. But there are still places where brushed motors make more sense. There is a huge application of brushed motors in home accessories, industrial sections, medical equipment, robots, electric cars, power instruments etc.
At the end, the cost of brushed and brushless motors differs based on the definite uses and necessities. Brushless motors are usually more costly, but they provide better efficiency and higher life-span. Thus, the higher cost of brushless motors can be replaced by its less operating cost and higher reliability. Brushed motors are perfect for daily applications for the people who have less or no electrical knowledge. Brushless motors are mostly used for the matter where longer life-span is quite important, otherwise brushed motors occupy 95% of the motor market.