Brushless Motors: History, Types and Functions

The Brushless DC motor revolutionized the electric propulsion industry. It is durable, efficient, and streamlined in design and allows vehicles such as RC cars and drones to function with optimum efficiency and control.
This article pays homage to brushless electric motors by going through their structure, different types, applications, and advantages.  

What Is a Brushless Motor?

A brushless motor (BLDC or BL) is an electric motor that runs on direct current (DC) and does not use the mechanical brushes and commutator of a traditional (brushed) motor to function. Although its initial expenditures are greater, this type of motor offers obvious benefits over its counterpart and is more cost-effective in the long term.

The first brushless DC motor, dubbed a “DC machine with solid state commutation” was invented in 1962 by T.G. Wilson and P.H. Trickey, as a result of advances in solid-state technology in the early 1960s.

Early BLDCs had the disadvantage of not being able to generate a lot of power, despite their durability. They were able to generate as much (or more) power as brush motors did before stronger permanent magnet materials became available in the 1980s. Robert E. Lordo produced the first large-scale brushless DC motor in the late 1980s, with ten (10) times the power compared to previous models.

Modern BLDCs have overcome many of the drawbacks of brushed motors by combining higher output power, smaller size and weight, improved heat dissipation and efficiency, wider operating speed ranges, and extremely low electrical noise. They feature no mechanical parts that might wear out, resulting in greater dependability and shorter maintenance intervals in commercial and industrial applications.

brushless electric motors are the preferred choice for computer disk drives, robotics, and airplanes since they do not require a physical commutator.

How Does a Brushless Electric Motor Work?

brushless electric motors consist of a rotor, stator, and electronic controller. The stator winding generates a revolving magnetic field that propels the magnetic rotor forward. A three-phase voltage is given to the coil to create this magnetic field.

So, how does the system distinguish between which coils are powered and which should be? A specific electrical controller is employed for this purpose. The Current is turned on to orthogonal (perpendicular) windings by such an integrated commutating mechanism. It also has sensors that determine the location of the rotor. Hall sensors are most commonly utilized, however photoelectrical, inductive sensors, and resolvers are also used.

Related Article: Brushless Vs. Brushed Motors

Based on its structure, A brushless dc electric motor can be of two kinds: Inrunner or outrunner.

In inrunner models, the rotor is encircled by the stator winding while in outrunner ones they switch places.

The stator of a typical brushless motor has a three-phase winding, while the rotor contains a permanent magnet. It’s also available in single-phase, dual-phase, and three-phase configurations. As previously stated, the stator winding generates a revolving magnetic field that propels the magnetic rotor forward. A three-phase voltage is given to the coil to create this magnetic field.

So, how does the system distinguish between which coils are powered and which should be? A specific electrical controller is employed for this purpose. Current is turned on to orthogonal (perpendicular) windings by such an integrated commutating mechanism. It also has sensors that determine the location of the rotor. Hall sensors are most commonly utilized, however photoelectrical, inductive sensors, and resolvers are also used.

What Are Brushless Motors Used For?

BLDCs perform many duties that brushed DC motors used to take care of, but high price tags and the control complexity have prohibited BLDCs from totally replacing brushed motors in all sectors. However, they have grown to dominate numerous fields, including computer hard drives and CD/DVD players. BLDCs are used exclusively to power small cooling fans in electrical devices. A 12v brushless motor is a great choice for home appliances and light-duty power tools while the 18 and 20 versions are used for more heavy-duty applications.

These efficient motors are common in cordless power tools, where the improved motor efficiency allows for extended durations of usage before the battery has to be recharged. Direct-drive turntables for gramophone records employ low-speed, low-power brushless motors.

Many current cordless tools run on a brushless DC electric motor, including string trimmers, leaf blowers, circular and reciprocating saws, and drills. These sources of power have more benefits over brushed ones (low weight, high efficiency) for portable, battery-powered equipment than for big, stationary tools plugged into an AC outlet, hence adoption has been faster in that part of the market.

Brushless DC Motors Advantages:

What Are the Disadvantages of Brushless Motors?

As many advantages Brushless motors have there also are a number of drawbacks to them:

• Cost: Brushless motors have a number of drawbacks, all of which stem from their increased design complexity. To sequence the right charge through the stator coils, BLDCs require a switching controller. This increases the cost of production, which is reflected in the higher starting cost.
• Complication: Adding complexity increases the risk of failure. We couldn’t locate any research that compared the failure rates of brushed vs. brushless power tools, although it’s often assumed that more complicated equipment is more likely to fail.

What is the Best Option, Brushed or Brushless?

Since 1856, brushed DC motors have been used for electrical propulsion, cranes, paper machines, and steel rolling mills, and they are still widely used today. Brushless DC motors with electronic speed controller devices have largely replaced brushed motors in many applications since their brushes wear out and need to be replaced often. Due to high application demands and high-electric discharge noise (called ESD, notably in aerospace applications), brush wear became a severe disadvantage, and a new motor was produced.

Brushless motors, for starters, provide exceptional performance and long cycle life. These types are required in applications where a fast rotation speed and resistance to overheating are both required. Such equipment is utilized in robots, medical equipment, CNC machines, and other expensive and critical industrial equipment as part of the cooling system. Brushless devices of the same size are more powerful than brushed ones. It’s also employed in situations where long-lasting, low-maintenance electric motors are required.

Based on their brush type, brushed motors’ life ranges from 1,000 to 3,000 hours on average, but a brushless DC motor may last for tens of thousands of hours! So, if you want a motor that will last a long time, go for the latter.

FAQ ❓

Is A Brushless Motor Really Better?
Yes. Brushless motors are more durable and efficient than brushed ones. They have a longer lifespan, produce less noise, and require less maintenance.

What Are the Different Types of Brushless Motors?
There are two types of brushless motors: Inrunner and outrunner. In the inrunner models, the rotor is at the center encircled by the stator winding while in the outrunner ones, the rotor surrounds the winding.

Ronix

13 December 2021