We have a brushless generator

More power without brushes

Brushless motors are now commonplace in cordless tools - they are small, powerful and make mobile devices even more compact. But users also benefit from the advantages of brushless technology when it comes to power supply units.

There are things in life that you don't question any further - you just know that they are a little better than the conventional variant. Brushless motors, for example. The term “brushless” has long been on everyone's lips, especially in connection with cordless machines. And more and more line-operated devices are being equipped with brushless motors. But what does the technology actually bring? To answer that, the mechanics behind it must first be understood. We asked Metabo.

No carbon brushes - what then?

A brushless motor does not have carbon brushes. This is why there is no mechanical contact between the moving rotor and the stationary stator in brushless motors for the transmission of electrical energy. Otherwise, the brushes create the electrical connection between rotor and stator via commutators and are worn out by mechanical abrasion and the fire of the brush. With brushless motors, there are no commutators or carbon brushes, which are the main wear factors in conventional motors. In the brushless motor, the rotor is equipped with magnets. It can be encapsulated by a special construction, so it is protected from damage by particles. The engine thus has a longer service life overall.

Less heat, higher efficiency

The bottom line is that less maintenance means more uptime and efficiency. In devices with conventional motors, the mechanical friction and the resistance of the carbon brushes lead to a loss of electrical energy. This is not the case with machines with brushless motors, since brushless motors work without carbon brushes.

Accordingly, less energy is lost in the motor. Less heat develops and at the same time a higher degree of efficiency. This means that users can use their machines for longer than comparable devices with brush motors.

Thanks to high-quality magnets in the rotor, brushless motors in power supply units are also impressive in terms of energy efficiency: Compared to conventional motors, they require less electricity with the same output power and thus have a positive effect on the energy balance of the tools.

Light and compact for continuous use

But not only their long service life and reliability speak in favor of brushless power tools. The brushless motor is smaller than a conventional motor with comparable performance. This compactness is an advantage especially for cordless machines, but the mains-connected machines are also a lot more pleasant to use in everyday work thanks to their handy design. And: brushless motors are real lightweights. Tradespeople have a better grip on their tools and can work with them for longer.

The best remedy for fluctuations in performance

For example, grinding work can sometimes take a long time. For example, when stairs or doors have to be sanded down. So it's good when the machine guarantees constant speeds, even when the application is under heavy load. Because the constant speed is important for high work performance. The wired Metabo eccentric sanders SXE 150-2.5 BL and SXE-5.0 BL with their powerful brushless motors are therefore ideally suited for demanding continuous use, the manufacturer promises.

This is also evident when users demand particularly high levels of power from their devices or when power fluctuations occur on the construction site due to the use of extension cables, cable drums or generators: Brushless devices can easily cope with such load fluctuations in the power grid thanks to a compact inverter circuit.

This enables users to work even faster with brushless machines and, on balance, achieve better results than with devices with brush motors.

Is it worth the investment? - Bundled advantages

We mainly know brushless motors from cordless tools. But this technology is also being used more and more by their network-operated colleagues. But is it worth the investment? We think: Yes, because motors without carbon brushes are powerful, robust and reliable. In addition, compared to machines with brush motors, the devices are lighter, more space-saving and, thanks to optimized ergonomics and more compact design, they sit particularly well in the hand. In addition, there is less wear and tear, less heat generation and maintenance costs as well as a higher degree of efficiency than comparable devices with conventional motors. Everything together promises longer operating times and more efficiency for the construction site and workshop. Brushless machines are the right choice for those who need maximum performance and who often have machines in continuous operation. (mh / source Metabo)

Expert in the field of brushless technology: Bernd Fleischmann is Director of Product Development and Quality at Metabo.
Photo: Metabo

At a glance and further information

Motor performance meets battery knowledge

Brushless explained in brief

The brushless motors in power tools are mostly so-called internal rotor motors.

The energy is not transferred mechanically into the rotor via carbon brushes; instead, the rotating magnetic field is generated electronically in the stator. This creates less friction, which increases efficiency, performance and service life and reduces heat generation. In addition, brushless devices are more compact and lighter than their counterparts with brushed motors with the same performance.

Metabos role in the battery segment

Metabowerke GmbH, manufacturer of cordless, mains and compressed air tools for professional users, has taken on a pioneering role in the cordless segment in recent years with its high-current LiHD technology - and not only in terms of battery performance. The 18 V battery with ten battery cells delivers up to 1600 W of power with a capacity of 8 Ah - enough to use two packs, for example. B. to operate a mobile table saw.

But the vision of the wireless construction site went even further. The LiHD technology also forms the basis of the CAS (Cordless Alliance System) battery system, which includes machines and power tools from various industry-specific manufacturers. The highlight: Within the system, all batteries are compatible with each other, including the charger. It includes 150 machines and devices from Metabo, Rothenberger, Mafell, Eisenblätter, Collomix, Haaga, Electrostar (Starmix), Eibenstock, Steinel, Rokamat, Elried / Edding, Birchmeier, Fischer, Prebena, Cembre, Pressfit and Jöst Abrasives.



BM online 02 | 2020