(Part II in the series on brushless motor power tools)
When the engine becomes “smart”
In the first part, we presented the operation of brushed motors, their advantages and disadvantages, and the evolution of electric motors in the world of DIY tools. Now we turn our attention to brushless motors, to discover why they are quieter, more durable, and more efficient in every aspect.
1. Brushless motor construction
In contrast to the brushed motor, the brushless motor is built on a completely different principle:
Key components
- Rotor (forgórész)
- Does not contain a coil.
- Employs permanent magnets (most commonly neodymium), which ensure a strong magnetic field.
- Advantage: lower heat generation, higher power-to-weight ratio.
- Stator (állórész)
- Houses the coils, with current regulated by the electronic controller.
- Heat is generated here, but as this component is located on the outside, it can be easily dissipated through the motor casing = improved heat dissipation.
- Electronic control (ESC – Electronic Speed Controller)
- The ‘brain’ that regulates the rotor’s rotation.
- It monitors the rotor’s position and current draw, and controls the current supplied to the coils accordingly.
- Provides overload protection, thermal protection and a soft-start function.
2. How does a brushless motor work?
The essence of its operation: the electronics assume the role of the carbon brush, that is, they control the direction of the magnetic field.
- The rotor is a permanent magnet, while the ESC supplies current to the stator coils.
- The electronics determine the rotor’s position using sensors (Hall sensors) or by calculating it from the feedback voltage.
- Current is supplied to the stator coils at the appropriate moment, allowing the rotor to rotate continuously.
Control of speed and torque
- The electronic control of the motor enables a wider speed range than that of a brushed motor.
- By operating at higher speeds, greater performance can be achieved with a smaller motor, provided the torque is optimised through gear ratios.
- The electronics continuously monitor the load, adjusting the torque as required; energy-efficient operation.
3. Advantages over brushed motors
The advantages of a brushless motor go beyond mere marketing slogans – they can genuinely be experienced by the user:
| Aspect | Brushed motor | Brushless motor |
|---|---|---|
| Wear | Yes, brushes and commutator | Minimal, no brushes |
| Maintenance | Regular replacement of brushes and bearings | Virtually none |
| Sparking | Significant | None, controlled electronically |
| Noise level | Medium to high | Low |
| Efficiency | 60–75% | 85–90% |
| Heat dissipation | Rotor inside – difficult | Stator outside – easy |
| Lifespan | 500–1,000 operating hours | 5,000–10,000+ operating hours |
| Protection | Mechanical | Electronic, overload and thermal protection |
| Energy consumption | Battery depletes more quickly | Battery life extended by up to 30–40% |
| Dynamic performance | Limited | Higher speed and torque |
4. What does all this mean in practice?
- Quieter operation – no sparking, less vibration.
- Longer battery life – more energy efficient.
- Higher torque and performance – in a more compact machine.
- Safer operation – in the event of overload or jamming, the controller switches off the motor, ensuring nothing burns out.
- More durable machines – less maintenance, longer lifespan.
5. Magnets and performance
The neodymium magnets in the rotor play a key role in boosting performance:
- A stronger magnet generates a greater magnetic field, providing higher torque.
- High performance in a small space; compact, lightweight machines.
- Manufacturers often combine a high-speed brushless motor with a planetary gear to deliver high torque at lower output speeds (for example, in screwdrivers and angle grinders).
6. What happens if the motor jams?
This is the most important difference compared to brushed motors:
- Brushed motor: if it becomes jammed, the commutator may short-circuit; intense sparking; the commutator is damaged; the motor ‘burns out’.
- Brushless motor: the electronics continuously monitor current draw and rotor position; if the rotor jams:
- The ESC switches the motor off
- No short-circuit occurs, no sparking, and the motor is not damaged
- Result: greater operational reliability, longer lifespan, fewer ‘unexpected failures’.
7. Typical applications in the DIY workshop
- Cordless screwdrivers and drills – quiet, long runtime, precise torque.
- Angle grinders and flex tools – high speed, low maintenance.
- Chainsaws and hedge trimmers – lighter machines, longer uninterrupted use.
- Robot and smart devices – electronically controlled motor, easily integrated.
8. The brushless motor opens up a new dimension
The brushless motor is not just another ‘gadget’: it elevates the DIY experience to a new level.
- Quieter, more durable, more efficient.
- Greater performance in a more compact size.
- Electronic control ensures overload protection.
- Less maintenance, longer battery life.
In the upcoming Part III, we share practical experiences, highlight potential errors, offer maintenance tips, and discuss key factors to consider when choosing, making the benefits of brushless motors tangible in everyday DIY tasks.
