What better electric screwdriver brush or brushless
Brushless cordless screwdrivers: how to choose, top 10 best
Familiar to all cordless screwdrivers are equipped with collector motors with current switching in armature windings by means of brushes. Brushless screwdrivers, by contrast, have a brushless motor. The functions of the collector-brush unit (BCU) are performed by the electronic control unit. The difference is that it switches the current in the stator windings, not the rotor. The armature, on the other hand, has no coils. To eliminate sliding contacts its magnetic field is created by permanent magnets. The torque for feeding current into the stator windings is detected by means of rotor position sensors (RPD), which operate on the basis of the Hall effect.
Pulses of DPR together with the speed regulator signal are processed by the microprocessor. The processing results in electrical pulses modulated in width. This is the so-called PWM signal. The resultant pulse train is fed to the current amplifiers (inverters). Their outputs are connected to the stator windings. Inverters, in accordance with the output signals of the microprocessor unit, commutate the current in the stator coils. The alternating magnetic field caused by pulses of this current, interacting with the constant magnetic field of the rotor, causes the armature to rotate.
Features of Brushless Screwdrivers
The name mentioned literally means “brushless motor”.
The unit is characterized by the absence of a collector and brush block in its design.
Brushless DC motor devices are sometimes referred to as BLDC.
Synopsis! The design of this motor uses a special electronic amplifier that replaces mechanical switching of the contacts.
The electronic sensor in it detects the angle of rotation of the rotor and controls the semiconductor switches. The absence of sliding contacts reduces friction and increases the operating time of an electric screwdriver.
Brushless type electric motors provide increased efficiency and resistance to mechanical wear of parts.
In terms of advantages they have:
What electric screwdriver to buy in 2020?
|The Best 12-volt Screwdrivers||1||DeWALT DCD701D2 Li-Ion 2.0 Ah 12 V x2 Case TSTAK 57.5 N-m|
|2||Makita DF333DWYE 30 N-m|
|3||Bosch GSR 120-LI 1.5Ah x2 Case|
|The best screwdrivers powered by 18 V||1||Bosch GSB 18-2-LI Plus 2.0Ah x2 Case 63 N-m|
By replacing the brush unit with an electronic assembly, the motor efficiency can be increased by up to 1.5 times. With commutatorless models, it is up to 90%, so the energy is used much more efficiently. This is especially important for cordless tools, which is why commutatorless motors are more common in standalone tools.
1.5 times more energy efficiency for a corresponding increase in autonomy. That is, if you can tighten 200 screws with a brush tool on a single charge, then the brushless tool with the same power and battery capacity will tighten all 300.
Brushless electric screwdriver is in most respects better than a brushless one: it’s more compact, efficient, safer and has a longer life. But the high price makes the purchase of such a tool for domestic use not always justified. If you don’t need an autonomous tool, a budget wire model with a collector motor, such as SPETS BShE-400M is enough for all tasks. It doesn’t make sense to overpay for an improved motor, and a power deficit when supplied from a socket certainly won’t bother you.
economy also makes sense when choosing a selfcontained electric screwdriver for occasional home use. If you don’t need to twist screws by hundreds, it is enough to use a cordless model with a traditional collector motor, such as the P.I.T. PSR 24-D1. After all, the cost of such a device is about half as much as its commutatorless counterpart.
For semi-professional and professional use, the choice, brush or brushless electric screwdriver is better to take, you can remove. Definitely, it is worth it to overpay and to take a model with a modern motor like DeWALT DCD777S2T. You’ll pay more, but you’ll get a more convenient and self-contained tool that will handle your tasks better, thereby allowing you to earn more.
Brushless electric screwdriver is in most respects better than a brushless one: it is more compact, efficient, safe and durable. But the high price makes buying a brushless electric screwdriver for your home not always a good idea. If you don’t need an autonomous tool, a budget wired model with a collector motor such as SPETS BShE-400M is enough for all tasks. It makes no sense to overpay for an improved motor, and you won’t be bothered by power shortages when supplied from the outlet.
When choosing a self-contained electric screwdriver for occasional home use, saving money also makes sense. If you don’t need to drive hundreds of screws, it’s enough to choose a cordless model with a traditional collector motor, such as the P.I.T. PSR 24-D1. After all, the cost of such a device is about half as much as its commutatorless counterpart.
For semi-professional and professional applications, the choice, brush or brushless electric screwdriver is better to take, you can remove. You should definitely overpay and buy a model with a modern motor like the DeWALT DCD777S2T. You pay more, but you get a more comfortable and autonomous tool that can better cope with the task at hand, thereby allowing you to earn more.
Tips for Choosing
First evaluate the tasks that will be performed using this device. Particular attention is paid to the autonomy of the device. For example:
- Li-ion batteries are preferable for professional work. Such a battery has a service life of 5 years. This parameter is indicated by the manufacturer.
- Nickel-cadmium batteries are more efficient for domestic tasks. This type of battery holds a charge for 4-5 hours. This is just enough time to tighten a few screws. Nickel-cadmium batteries lose their autonomy over the years. However, they are resistant to frost.
Important! It is better to remove the battery if the device is not used for a long time. It should be stored at room temperature. Exposing the electric screwdriver to sunlight is not recommended.
Thus, this article has provided basic information regarding brushless screwdrivers. It is easy to make a choice based on the data presented.
Design and principle of operation
The cordless tool has taken its place in the set of tools you need. When buying equipment for the house, the owner should become familiar with the principles of its operation.
You can consider the features of how the brushless motor in an electric screwdriver works:
- Current is switched in the stator windings. There is no coil on the armature, and the magnetic field is created by the magnets installed inside the housing.
- The time when it is necessary to connect the electricity is regulated by built-in sensors. The hall effect is used. Short electrical pulses and speed signals regulating operation are passed on to the internal processor. This action is commonly referred to as a PWM signal.
- The alternately generated pulses are fed into the amplifiers which amplify the current. Inverters (amplifiers) connected to the winding on the stator. These elements store the current produced by the coils, and transfer it via pulses from the internal processor.
The result is a magnetic field that makes the armature rotate and the tool begin to work.
The tool is brushless
Brush-type electric screwdriver
Brush-type motors. proven technology. On the side of such a tool. small size, affordable price, long life.
Design and principle of operation
Brush motor is another name for a collector motor. It consists of:
The rotor is wrapped with copper wire. The current creates a magnetic field around the winding that converts electricity into mechanical energy. This sets the armature in motion.
The purpose of the commutator (collector) is to switch the voltage from one winding to the other and so alter the direction of rotation of the armature. To allow current to flow from the commutator to the coil windings, the motor has two graphite brushes, one on each pole of the battery. They provide a constant change in the direction of the current. This also changes the magnetic field which allows the armature to continue rotating.
The rotor with collectors and brushes is located inside the stationary stator. It also contains another coil or permanent magnet. This element produces a magnetic field that is inverse to the rotor field in polarity. Their interaction is what sets the armature in motion.
Pros and cons
- The technology is old and therefore the tools are cheaper than the brushless ones.
- Easy to repair. If brushes break down, you only need to replace them, not buy additional parts or a whole new motor.
- Small dimensions, easy to transport.
- Relatively low efficiency of up to 60%. Much energy is expended in creating friction between the brushes and the collector.
- Because of that graphite brushes are subject to rapid wear and tear. They must be replaced every 2 to 3 years. Additionally, graphite clogs the collector and can cause the electric screwdriver to malfunction.
- Brush tools are not capable of producing more than 3,000 rpm. Enough for home use, but for more demanding tasks, brushless models seem preferable.
- Friction between brushes and commutator creates sparks. Therefore, it is possible to work with the tool only in places without risk of fire, far from flammable substances. Care must also be taken to prevent the device overheating due to friction and to allow it to “cool down”.
Brush type electric screwdriver
Brush-type motors. a time-honored technology. On the side of this tool. small size, reasonable price, long life.
Construction and principle of operation
Another name for a brush motor. the collector motor. It consists of:
General structure of the motor The rotor is wrapped with copper wire. The current creates a magnetic field around the windings that converts electricity into mechanical energy. This puts the armature in motion.
The task of the commutator (collector) is to switch the voltage from one winding to the other and therefore change the direction of rotation of the armature. To allow current to flow from the commutator to the coil with the winding, the motor has 2 graphite brushes. one on each of the battery poles. They provide a constant change of direction of current. This also changes the magnetic field, causing the armature to rotate further.
The rotor with collectors and brushes is located inside the stationary stator. There is also another coil with windings or a permanent magnet. This element produces a magnetic field which is the inverse of the rotor field in polarity. Their interaction is what sets the armature in motion.
Pros and cons
- The technology is old and therefore the tools are cheaper than brushless tools.
- Easy to repair. If the brushes fail, it is enough to replace only them, and not to buy additional parts or a whole new motor.
- Small size, easy to transport.
- Comparatively low efficiency of up to 60%. A great deal of energy is expended in creating friction between the brushes and the collector.
- Because of this the graphite brushes are subject to rapid wear and tear. Brushes must be replaced every 2-3 years. In addition, graphite clogs the collector, and this can be the reason for the failure of an electric screwdriver.
- Brush type tools cannot achieve more than 3,000 rpm. They are good enough for your home, but for more demanding tasks brushless models are preferable.
- Friction between brushes and commutator creates sparks. That’s why the tool can only be used in places where there is no risk of fire, away from easily flammable substances. It is also necessary to ensure that the device does not overheat because of friction, and give it a “rest” to cool down.
The advantages of a brushless motor in theory
We’ve already got the mechanics of a brushless motor sorted out, and now it’s worth looking at the positives and negatives of such tools.
There are several advantages of these motors:
- They do not have the problems that brush models have. They are more resistant to wear and tear, since the brushes do not generate any internal friction. The level of ignition is also lower. Lack of sparking allows for operation in the most demanding conditions.
- Easier torque control. Number of levels (15), allows you to immediately select the desired mode and just press the button. They have a higher level of efficiency.
- Economical use of electricity. This is particularly important. If the motor is a cordless motor. The tool can be used on any material.
Important! Also, brushless motors can deliver their maximum output almost immediately.
Mechanical part of the tool designed to clamp the bits and send them in a rotary motion. Usually mounted on the spindle thread. Can be fixed by screw, clip or ratchet. High-quality models have a safety catch that enables the drill bit or bit to be clamped without additional cranking.
Almost all modern professional and hobbyist screwdrivers are fitted with a three-jaw self-centering chuck. This allows you to quickly change attachments, reinforcing them for a long and rich work. Inside the chuck there is a hexagonal hole for fixing the shank of the bit. Usually the attachment takes place between all 3 cams by light rotation of the coupling.
to install the bit, grab the lower sleeve and twist the upper one, it allows the jaws to open. To accelerate the process, the mowing head can be locked in place by grasping the upper clutch and pressing the start button to clamp, and the reverse button to unclamp.
Why are brushless tools so expensive?
The main disadvantage of this tool is its high price. It is due to the presence of an expensive power board and electronic control. This makes the motor more reliable.
But the high price of such a tool sometimes becomes a decisive factor when buying a tool. Which electric screwdriver is better brushed or brushless each user decides for himself. And many tend to favor the cheaper product.
Important! Brushless tools always cost a lot of money to replace.
Why brushless tools are so expensive
The main disadvantage of such tools is their high price. It is caused by the presence of an expensive power board and electronic control. That makes the electric motor more reliable.
But the high cost of such a tool is sometimes a deciding factor when buying a tool. Which electric screwdriver is better brushed or brushless each user decides for himself. And many tend to favor the cheaper product.
Important! Replacing parts with brushless tools is always expensive.
What electric screwdriver to choose
Of the variety of tools available on the power tool market, we can recommend brushless screwdrivers of the following, both Russian and foreign. Bosh, Enkor, Hilti, Vihr, DeWALT, Ermak, Makita, Hitachi, Ridgid, AEG, GreenWorks, Black-Decker.
The choice of a particular manufacturer and its model of electric screwdriver depends on the tasks that will be entrusted to this tool and on the available budget.
According to most customers in the Russian market of power tools the most trusted are brushless screwdrivers, such as. “Makita and Interskol.
If the choice in favor of a brushless tool is obvious, it is not so clear what kind of battery it should be equipped with. Here we can give two recommendations:
- Lithium-ion batteries are preferred for regular professional work. They can be recharged an unlimited number of times, have no so-called “memory effect”. They should be accompanied by a reliable professional battery charger. Such batteries work exactly as prescribed in their warranty. about 4-5 years.
- Nickel-cadmium or nickel-metal hydride batteries are better for occasional DIY jobs. It does not wear out over time, it depends on the number of use cycles. Another advantage of them, in addition to the budget price, is frost resistance.
- If you are not using the electric screwdriver for a long period of time, store the tool with the battery disconnected. The optimum storage temperature is about 15 degrees Celsius. Away from heaters and sunlight. If an oxide film appears on the contact pads, it must be removed with a solvent recommended by the manufacturer (to avoid damage to the tool itself). These are usually ethanol-based formulations.
Collector versus brushless: summary table
Now, a comparative characteristic of two types of tools in the form of a table with the key parameters.
|Features||Type of electric screwdriver|
|EFFICIENCY||Up to 60%||90%|
|Wear and tear||faster||longer|
|Long battery life||less||almost twice as long|
|Working in rooms with fire risk||higher risk||safely|
Which tool to choose after all
If you look at the above table, you can draw an unequivocal conclusion: Brushless screwdrivers win, as they say, all by one goal. Almost all characteristics are in their favor, and only a few parameters make the collector tool look preferable.
However it is on paper. Brushless equipment is better, more modern, but you have to pay well for this superiority. Before you shell out a solid sum of money, it’s worth answering yourself a few questions:
You don’t want to spend a lot of money on a brushless electric screwdriver that you might need just once or twice and gather dust in your closet the rest of the time.
For home work, a brush tool is enough
One of the main points with which to choose the type of tool is the possibility of repair. Even if you exclude the mandatory replacement of brushes every couple of years, the collector unit is likely to go out of the LADA already when the money paid will be fully worked out. You don’t mind throwing out your old machine and buying a new one for the same money.
Conclusion! If an electric screwdriver is needed only for occasional local work in the house, the collector tool will suffice, too. But the replacement of one part in a brushless electric screwdriver will entail the purchase of several more (otherwise. no way), which will amount to half to 75% of the price of a new device. It will probably last longer than a brush type, but if it breaks, there is no sense in repairing it.
The three main criteria in choosing the type of electric screwdriver are budget, purpose, and planned frequency of use. And to see the difference in the work between the collector and brush tool can be seen here: