Brushless And Brushless Screwdriver What Is The Difference
12 reasons why you should choose a brushless screwdriver The article talks about a brushless screwdriver. What is this tool? What are its advantages over a tool with a brush motor, disadvantages. How to choose a tool: with a metal or plastic gear? The best manufacturers.
12 reasons why you should choose a brushless screwdriver
After the widespread use of the brushless cordless screwdriver on the market, it became easier to work with the assembly of furniture, fastening siding, installing drywall. This device does not have carbon brushes that could cause a short circuit. Also, due to the absence of a cord, it has become more mobile and convenient to use.
What is this tool?
Common models of cordless screwdrivers are designed with collector electric motors.
The current in them is switched through the armature winding thanks to the carbon brushes.
And brushless screwdrivers work with brushless electric motors that do not have brushes.
The functions that the brushes performed in conventional screwdrivers are transferred to the electronic control unit in these models. It is capable of switching the current to the stator winding, not the rotor. There are no coils on the anchor. To exclude the possibility of contacts slipping, the magnetic field in it is generated using permanent magnets. In stator windings, the required moment for current supply is created using rotor position sensors. They, in turn, work according to the Hall effect principle.
The pulses from the rotor position sensors are received by the microprocessor together with a signal that regulates the rotation speed. After finishing the processing, electrical impulses are generated with precise width settings (PWM signal). The resulting combination of pulses is transmitted to the inverters (current amplifiers). Their outputs are connected to the stator winding. In accordance with the information received, the inverters create a current in the stator coils. The resulting pulses create an alternating magnetic field. When it interacts with the constant rotor field, the armature begins to twist.
The principle of operation and the difference from the brush:
Advantages and disadvantages
Modern models of brushless screwdrivers have a large number of pros and cons. Among the advantages are:
- It is easy to adjust the speed and change it within wide limits.
- The collector-brush assembly is excluded from the design. This helped to simplify maintenance and repair of the screwdriver, and also to reduce the possibility of malfunctions.
- Now, short torque overloads are transferred much easier with a screwdriver.
- Low power consumption. Thanks to the economical distribution of energy, the efficiency of the tool is increased by up to 90%.
- The service life of the screwdriver has increased.
- Less heat compared to a brush screwdriver.
- The security system has improved. Due to design changes, the possibility of sparking is excluded. This allows you to work safely in rooms with explosive gases.
- Long battery life (up to 2-3 days).
- The size of the tool has decreased, it has become lighter.
- For screwdrivers with a reverse function, it became possible to use the same power for reverse and forward twisting.
- During an increase in the loads on the chuck, the torsion speed does not change (in models with KShU it dropped significantly).
- Smoother and quieter operation.
Proceeding from this, each master decides for himself whether to opt for a brush or brushless instrument.
Cordless drill / screwdriver. Hand tools designed for tightening / unscrewing screws, self-tapping screws, screws, dowels, as well as for drilling holes in wood, concrete, metal and other materials. The screwdriver is powered by a rechargeable battery, which allows you to use the tool in the absence of power.
A screwdriver consists of an electric motor that produces a rotary motion. The planetary gearbox forms a mechanical transmission from the motor to the spindle, on which the chuck of the screwdriver is mounted. To change the screwing depth, screwdrivers have a torque regulator coupling. The speed mode switch allows you to switch the operation of the screwdriver between drilling and inflation modes. A keyless chuck or chuck is required to connect working attachments such as bits, key heads and drills.
The most important element of a screwdriver is the power supply. Accumulator battery. Batteries are available with nickel-cadmium (Nicd) battery and lithium-ion. Li-Ion. By tension. Cordless drills are divided into:
3.6v, 7.2v, 9.6v, 10.8v, 12V, 14.4v, 16.8v, 18V, 36V.
The most popular battery voltage values. From 10.8 to 18 volts. The capacity of the battery will change in Ampere-hour [Ah]. It affects the duration of operation from one battery. Popular values are 1.3. 8 [Ah].
Max torque determines how large the diameter and length of the screw the screwdriver can handle and the diameter of the hole to be drilled. Measured in Newton meters. [Nm]. To increase / decrease the power of the tool, torque control is used, this is done in order to tighten screws and screws with gentle effort, thereby avoiding thread stripping and grinding of the bit heads.
To change the direction of rotation of the spindle, that is, to tighten and unscrew fasteners, use the function reverse. To control it, a switch of 3 modes is installed on the screwdrivers, the central one blocks pressing the engine start button.
Cordless drills sometimes have shock mode. Rotating with an axial impact like a hammer drill will allow you to more effectively drill holes in brick and concrete. As an add-on there is a function backlight, as a rule, all new models are equipped with a flashlight.
Advantages and disadvantages
Among the advantages are:
- The ability to adjust the speed. At the same time, the user has a wide range of settings for this indicator, depending on the work performed and the working surface.
- There is no collector-brush assembly in the design of such a unit, so the tool breaks less often when used correctly, and maintenance does not cause problems.
- The screwdriver is better able to handle heavy loads associated with increased torque.
- Battery energy is consumed economically.
- The efficiency of such equipment is 90%.
- The ability to use the screwdriver in a hazardous environment with the presence of an explosive gas mixture, since there is no arcing.
- Miniature dimensions and low weight.
- In both directions of operation, one power is maintained.
- Even an increased load does not cause a decrease in speed.
- Impressive value.
- The large size of the screwdriver, which makes it difficult to work with an outstretched arm and in hard-to-reach places.
What is a brushless motor
The development of semiconductor electronics in the 1970s led to the realization that the commutator and brushes should be eliminated in DC motors. In a brushless motor, an electronic amplifier replaces the mechanical switching of the contacts. An electronic sensor detects the angle of rotation of the rotor and is responsible for monitoring the semiconductor switches. Elimination of sliding contacts reduced friction and increased the life of the screwdrivers.
Such a motor provides higher efficiency and less susceptibility to mechanical wear. Brushless motors have several advantages over brushed motors:
- Higher torque;
- Increased reliability;
- Noise reduction;
- Long service life.
The insides of the motor can be completely closed and protected from dirt or moisture. By converting electricity into mechanical force, brushless motors are more efficient.
The speed depends on the voltage, but does not depend on the centrifugal force, and the motor operates in the set mode. Even with current leakage or magnetization, such a unit does not reduce performance, and the rotation speed coincides with the torque.
When using such a motor, there is no need to use a winding and a commutator, and the magnet in the design is characterized by a small mass and size.
Brushless motors are used in devices whose power is in the limit of up to 5 kW. It is irrational to use them in equipment of higher power. Over, the magnets in the design are sensitive to magnetic fields and high temperatures.
Brushless screwdrivers: features, advantages and disadvantages
- What is a brushless motor
- Brushless screwdriver: energy principle
- Advantages and disadvantages
- Comparison of collector and brushless tools
- How to choose
Cordless screwdrivers have become in demand due to their mobility and capabilities. The lack of dependence on a power source allows you to solve much more construction problems.
Top 3 best models
There is a wide range of similar products on the construction tools market. We have selected 3 of the most successful models:
- Metabo BS 18 LTX. German-made screwdriver. It has a keyless chuck, powered by an 18 V battery. Maximum torque 110 Nm, suitable for working with wood and metal. Spindle lock, integrated overload protection and speed setting are available as options. There is a hook for wearing on the belt. Sold in a case without battery and charger;
- Dewalt DCF887N-XJ. Compact brushless screwdriver from a famous American brand. It is painted in the traditional yellow-black color for the manufacturer, which is convenient for searching in a cluttered object. Equipped with socket head chuck. There is a pulse mode and the possibility of shock work. The brushless motor is powered by an 18 V battery and has a maximum speed of 3250 rpm. The minimum configuration does not include a case and an additional battery;
- Makita DTP141Z. Professional tool with percussion and pulse operation. The maximum torque is 150 Nm. Suitable for working with wood, metal, effectively unscrews rusted nuts. Equipped with a brushless electric motor and 18 V rechargeable battery. No battery and charger included. Hexagonal chuck. It is possible to turn on the backlight, the handle is rubberized and fits comfortably in the hand. Supplied in a box, tool weight. 1 kg.
When buying a tool for household or professional tasks, you should pay attention to the cartridge. The choice of shank-type nozzles depends on this. As a rule, powerful pulse models are equipped with only a hexagonal chuck.
How does it work?
The layout of such a tool is similar to a standard electric drill device. The basis of the apparatus is an electric motor that transmits torque to a planetary gearbox. It transfers this value to the keyless chuck or hexagon socket. The device also contains all the elements traditional for drills and a screwdriver:
- Speed regulator;
- Load limiting mechanism;
- A system of gears, carrier and satellites.
A distinctive feature of the impulse screwdriver is the brushless motor device. In it, the rotor and magnets, as well as the winding and starter, are reversed, which should be taken into account when repairing or servicing. This mechanism reduces wear on the main parts by up to 30%, and also allows you to significantly increase the load if necessary.
The power supply of the instrument depends on its configuration. Most often, the impulse screwdriver is equipped with a DC battery. For comfortable work, it is advisable to buy a device with a lithium-ion battery with a voltage of 16-18 V.
How to choose?
When choosing a model of a screwdriver, one should take into account the specifics and regularity of work. If you plan to use the tool often and intensively, then brushless professional models with a battery should be preferred. If you need a device for rare household chores (screwing a cornice, assembling furniture or hanging a shelf), then you can choose models with low power and mains supply. What to look for when buying:
- Weight and compactness of the model;
- Maximum torque;
- Automatic or manual switching on of the pulse mode;
- Ergonomics of the handle, rubberized elements on the contact parts of the body;
- The ability to switch speeds;
- Type of battery, its capacity.
If you already have special devices for working with fasteners, for example, a conventional screwdriver, impact drill and wrench, then the models with a pulse mode are not necessary. Most often they are used in construction, automobile workshops, where it is necessary to work with stuck and rusted fasteners.