Brushless Motor Guide | Songtian Brushless DC Motor Solution
A guide on understanding what a brushless DC motor is, how it works, types and benefits. A FAQs section. Read Now!
What is a Brushless Motor? Brushless Motor Meaning, Working, and Types
Brushless motors are fast becoming the standard for automotive systems. In the recent years, they have practically replaced the traditional brushed type. There are many reasons to explain this trend, such as the high efficiency and reliability of the DC brushless motor. With the world moving toward electric vehicles, these motors are becoming even more useful- and popular. If you’re interested in learning more about them, keep reading! This post explains their working and application.
What is a Brushless Motor?
First things first; what does “brushless motor” mean? Brushless means without brushes. So in simple terms, a brushless motor is a type of direct current motor that uses no brushes. They are also called BLDC motors, which is the short form for brushless direct current and sometimes abbreviated to just BL.
Brushed motors rely on brushes and a commutator to switch current to the coil windings. A Brushless motor does not need those. In their place, BL motors utilizes electronic switches or. This is commonly called electronic commutation.
The electronic commutation of BLDC motors allows for precision with speed and torque control. That, in turn, makes the motor perform well over a broad range of uses- both low and high rpm. The brushless motor technology also means more possibilities, such as automatically adjusting motor performance to match the situation.
Brushless motor applications cut across all sectors, from industrial engineering to consumer electronics and automotive systems. In industrial settings, the motor finds application in CNC drives and other precision installations. Consumer goods that use BLDC motors include computers, vacuum cleaners, fans, and many more.
In the automotive world, brushless motors are found in almost every vehicle part and system; cooling fan, oil pump, air conditioning blower, water pump, windows, and many more. The list is almost endless.
Consider this; the modern luxury car uses over 100 motors!
Why brushless motors? You may ask. There are many reasons, as explained below.
Advantages of Brushless Motors
Because of their simple construction and low cost, brushed motors used to be the first choice for automotive motors. Not anymore today. The development of the brushless technology has, in the recent years, made BLDC motors take their place. The benefits of brushless motors include the following.
- Higher efficiency as a result of low friction and electrical losses
- Electronic control and higher reliability, suitable for high precision applications
- Large torque at low speed, excellent for starting torque applications
- Higher speeds ranges for high rpm applications
- Maintenance-free operation that reduces operational costs
- Low noise and Long life. No friction and wear of a mechanical commutator
- Spark-free operation that allows safe use around flammable materials
- Excellent regenerative braking by entering the generator state during braking.
- Compact size. No brushes and commutator
- Sealed construction that prevents dust from entering the inside of the motor
The many brushless motor advantages make the device suitable for automotive applications where low energy consumption, small size, low noise, and electronic control are vital qualities. The need for spark free motors too, or those that can withstand dusty situations.
Brushed vs. Brushless Motors
Brushed and brushless motors use different parts in their construction. They also offer different performance levels and other characteristics. For example, BLDC motors use an electronic commutation while brushed motors use physical commutation. In a brushed motor, the coil windings make the rotating part. In a brushless motor, the rotating component is usually a permanent magnet or magnets.
In terms of performance BLDC motors are better in many ways. For starters, they offer a higher level of efficiency. The brushless motor efficiency can go up to 90% compared to that of brushed motors which peaks at 80%. This makes BL motors low energy combustion devices -and environmentally friendly.
With no brushes and commutators, brushless motors are more compact than the brushed types- and quieter. Apart from making them quiet, the brushless motor design also means a maintenance-free and longer service life. Because they do not spark, BLDC motors can be used in hazardous conditions that involve the presence of flammable materials.
Brushless motors also used pulsed power to operate. This translates to low heat levels in the windings. As a result, it’s usually possible to produce them in sealed housings. This reduces the chances of dust getting inside these motors, and extends their lifespan.
Brushed motors have their advantages. They’re cheaper and use a much simpler operation method. You can also operate the directly without the need for a controller. The brushless motor price is generally high, plus you cannot use them without a control circuit, popularly known as the brushless motor driver, ESC, or controller for the most advanced versions.
Overall, brushless motors are superior in many ways. Despite their higher cost, they offer more value and suit use in many different applications. In addition to industrial and consumer appliance applications, BLDC motors are the most used in today’s automobiles including the revolutionary electric vehicles.
Parts of a Brushless Motor
A brushless motor uses several parts to function, some of which are different from those of the brushed types. Despite the many versions of the motor, 3 components will always be present; stator, rotor, and electronic control circuit. These are the main parts. Others include the motor shaft, bearing, and position sensor. Here’s more about the brushless motor parts and their functions.
The stator, as the name implies, is the stationary component that either encloses the rotating part or lies inside it. It consists of a magnetic core around which is wound many turns of wire. The core is typically steel pieces laminated for insulation and glued together to form a stack. The Brushless motor stator function is to produce an ever changing magnetic field and move the rotor in a rotational motion.
The rotor is the part that keeps rotating when the motor is in operation. It’s usually a composed of permanent magnets and either inside the stator or outside it. A brushless DC motor rotor provides the magnetic field to oppose that of the stator, thereby causing motion. The number of poles in the magnet varies across different motors. The magnets are also different materials, with both variations affecting the motor performance in different ways.
Electronic Control Circuit
The brushless motor control board or circuit is the component that contains the electronics to operate the motor; phase detection, commutation, and motor control. It can be an advanced controller or a simple driver, also known as ESC. A brushless motor controller regulates many parameters than just speed and torque. A brushless motor driver or ESC, on the other hand, only regulates speed.
Other brushless motor components as mentioned earlier include the shaft, bearing and in some types of the motor, a sensor and gear mechanism. The bearing is the part that holds the shaft in place and ensures it rotates smoothly.
A brushless motor gear box serves to increase torque by providing gear reduction and is mostly found in motors that need to overcome large loads. A BLDC motor sensor detects the position of the rotor poles. The controller uses this signal to calculate when to switch current and to which part of the stator coil.
How a Brushless Motor Works
Brushless motors function like any other DC motor, only that the commutation is electronic and not by brushes or physical commutator. The brushless motor operation also involves complex processes that are electronically controlled. Here is a brief explanation of how brushless motors work.
Current flows into two of the stator coils. This generates a magnetic field around the coils, with one coil producing a magnetic field to oppose that of a rotor pole and the other to attract it. The opposing forces cause the rotor to turn.
The position sensor detects the magnetic pole signal of the rotor (or determines the back-EMF signal) and sends the data to the motor control. The controller compares this signal to perform logical processing and generates a corresponding switching signal.
The switching signal triggers the power switching components in the drive in a certain order, and the power supply current is sent to the stator coils. The logical relationship is allocated to each phase winding, which makes the motor rotate and generate continuous torque.
In order to control the brushless motor speed, the control circuit varies the amount of power sent to the motor coil by pulsing the current. Some BLDC motors only change the speed and use a driver circuit.
Torque is also important when it comes to the working of these motors. The brushless motor torque depends on two variables; stator winds current and the back EMF; the opposing voltage that the motor generates when in operation. The controller uses these values to regulate the torque as needed.
In some BLDC motors, a gear reduction is used to increase the amount of torque so it suits the application. This includes drive applications where the motor has to move a large load from rest. Next are the different types of brushless motors explained.
Types of Brushless Motors
Brushless motor manufacturers make the device in designs and modes of operation. Each type fits a specific application process also advantages and disadvantages for each, which determines your choice depending on the project. The main brushless motor types today include:
- Single pole
In-runner vs. Out-runner Brushless DC Motor
An in-runner brushless DC motor is designed with the rotating part (rotor) inside and surrounded by the stator (coil winding). The out-runner version has the position of the two components reversed with the stator inside and the permanent magnets, or rotor, located on the outside. Inner rotor motors perform better in high rpm applications since they pick up speed quickly while the outer rotor types suit low speed but high torque uses.
Sensored vs. Sensorless Brushless DC Motor
A sensored brushless DC motor uses a sensor (often Hall Effect sensor) to detect the position of the rotor poles. A Sensorless version does not, and relies of the electromotive force signal when the motor is running to do that. Sensored motors perform best at lower speeds. Sensorless BLDC motors, on the other hand perform better at higher speed when the stator coils are generating a significant back EMF.
Single-Pole Vs. Multi- Pole Brushless DC Motor
A single-pole BLDC motor, as the name indicated, uses a single magnet for the rotor. The multi-pole type uses several. Each design has its up and downsides. The single pole motor speeds up quickly and performs best at higher rpm. The multi-pole types offer higher torque but at the expenses of speed. As a result, they’re better used with high toque, low speed applications.
Brushless Motors FAQs
DC brushless motors are among the most widely used, especially in the automotive industry. They also use newer technologies and many people are curious to know more about them- and asking questions. So here, we listed and answered the most asked questions.
Q1. Are brushless motors better than the brushed types?
A. They are! DC brushless motors offer better performance, reliability, durability, and many other benefits. They are typically more expensive, though, and mostly do not suit dusty conditions. That said, the benefits of brushless motors far outweigh their drawbacks, which is why they remain one of the most popular types of motors today. Their prices have also reduced considerably over the years.
Q2. Are brushless motors quieter?
A. Brushless motors do not use physical contacts to switch the coil windings current. That means silent operation, unlike brushed motors that produce friction and electrical noise. Brushless motors also use low power. That translates to less noise when operating within similar power or voltage levels that of brushed types.
Q3. Do brushless motors spark?
A. They do not. With no brushes and commutator to make physical contact, brushless motors do not produce sparks. In addition to the quiet operation, that also makes them suitable for applications that involve hazardous environments such as operation around flammable materials.
Q4. Do brushless motors get wet?
A. They do, and should be kept away from water in most situations. Brushless motors often use sealed designs and are water resistant. However, they are not waterproof and water may still gain entry. This can lead to the motor getting damaged. To avoid that, always follow the manufacturer’s care recommendations instructions.
Q5. Do brushless motors wear out?
A. Just like any other mechanical device, they do, only that the wear is minimal. So they last a long time, much longer than their brushed counter parts. BL motors are also low-maintenance device that do not require much care; no parts to replace every several hundred hours and no components to keep lubricating now and then.
Q6. How do you maintain a brushless DC motor?
A. Despite being low-maintenance, brushless motors require talking care of. That means running the device in safe conditions unless it’s designed for the specific application or environment. In most cases, brushless motor maintenance involves cleaning the motor. A brushless motor inside will inevitably accumulate dust over time. That needs removing, usually using air.
Q7. Can you rebuild a brushless motor?
A. You can. With few mechanical parts, BLDC motors rarely go bad. When they do, the problem is often the bearing. One of the ways that is by listening in to the motor’s sound as it runs. A worn bearing will sound scratchy as the friction will have increased. A few brushless motor components are replaceable. In most cases, though, it’s more advisable to replace the motor.
Q8. How much do brushless motors cost?
A. It’s difficult to quote a specific price when it comes to BLDC motors. These types of motors are manufactured in many different types, sizes, and material qualities. That means different price tags. Nevertheless, the DC brushless motor price ranges from $100 and higher. The cheapest brushless motor may cost as low as $20 but these are the small types or those without many sophisticated features and parts.
Q9. What is the best brushless motor and ESC combo?
A. There is not one specific brushless motor that can be labeled as the best. Instead, it depends on what type of application you are using the motor for and how much power you need to operate it. In short, a brushless motor’s performance is gauged using many parameters which, in turn, depend on the type of motor, among other factors.
A cheap brushless motor, for example, may lack some parts such as controller and only come with a driver circuit. When choosing a brushless motor, cheap models are also likely to be of lower quality unless the manufacturer has chosen to lower the prices purposely. So it’s always recommended to do a comparison before settling for a particular brand.
With the emergence of e-commerce, it’s possible now to order for a brushless motor online. This is not only convenient, but offers you an opportunity to check the motor features before committing to make your purchase. Which is a good thing given the many types of the device.
Brushless DC motors are becoming the most preferred types of motor in the automotive world, and for good reasons. They provide higher efficiency, speed, and durability than traditional motors that use brushes. They are also reliable, low maintenance, quiet and compact, among other benefits. This post will hopefully help you make an informed decision for your project. With their many types and sizes available today, there will always be a model to fit your application.
In order to continuously meet the needs of customers and adapt to the booming development of the automotive market, Sontian has vigorously developed brushless motor products, and plans to move to Tangxia east Industrial Park, located in Ruian, with a new plant area of 80,000. Square meters, specializing in the production of intelligently controlled brushless motors, with an annual production target of 5 million units.
Create the Songtian brand and strive for the first in the industry. The people of Sontian are marching towards the goal with their solid steps!