Brushless vs. brushless motors: pros and cons
Brushless or standard brush motors? What are the pros and cons for each?
You’ve probably noticed the brushless motors on cordless drills, peorators, etc. etc seem to be the most powerful power tools in the DIY world.
But you’re probably wondering what a brushless motor is? It’s just another marketing gimmick? Let’s try to figure it out together, and make you real experts on brushless power tools.
What’s the difference between brushless and brushed motors?
First of all, brushless motors. Definitely not a marketing ploy. There are several distinct and significant advantages over their counterparts.
What really powers the engine?
In both brushless and brushless motors, magnets are responsible for the motor shaft.
In brush motors, the power source passes through two brushes (small blocks made up of small carbon filaments) on opposite sides of the motor shaft, one on each side.
These brushes physically make contact with a part of the motor called the commutator, which is attached to the motor shaft. The commutator transmits the electric current from the carbon brushes to another part of the motor, called the armature, which is also attached to the motor shaft.
It is simply a bundle of copper wires that are actually wrapped in tight coils. An electromagnetic field is created when it goes through an electric field.
Brushless motors are a bit more complicated, although they use the same basic principle of counteracting magnetic forces.
Remember that in a brush motor, the armature (copper wire) is attached to the motor shaft (rotor), and the N and S magnets are firmly fixed outside the motor. In a brushless motor, they snap together; the armature is on the outside of the motor (fixed) and the N and S magnets are on the rotor (rotating part).
However, without the carbon brushes from which the brushless motor is powered to create opposite electromagnetic fields?
Brushless motor requires an additional set of electrical components to operate. It is usually a small board that controls the power to the armature, and a sensor that is responsible for the movement of the rotor. When the board applies an electric current to the coils, the same opposite magnetic field is created and the magnets on the rotor (motor shaft) begin to rotate.
Which electric screwdriver to buy in 2020?
|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 Nm|
|3||Bosch GSR 120-LI 1.5Ah x2 Case|
|The best 18-volt screwdrivers||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. In brushless models it reaches 90%, so the energy is used much more efficiently. This is especially important for cordless tools, which is why brushless motors are more common in standalone tools.
1.5 times more energy efficiency results in a corresponding increase in autonomy. So, if a normal brush tool can drive 200 screws on a single charge, then a brushless tool with the same power and battery capacity can drive all 300.
Brushless electric screwdriver is in most aspects better than a brushless screwdriver: it is 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, then budget wire model with collector motor like SPETS BShE-400M is enough for all tasks. Overpaying for an improved motor makes no sense, and a lack of power from the wall outlet certainly doesn’t bother you.
When choosing a standalone electric screwdriver for occasional home use, saving money also makes sense. If you don’t need to turn screws by the hundreds, 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 brushless counterpart.
For semi-professional and professional use, the choice, brush or brushless electric screwdriver is better to take, you can remove. Definitely overpay and get a model with a modern motor like the DeWALT DCD777S2T is worth it. You will pay more, but you will get a more comfortable and autonomous tool that can better cope with the task at hand, thereby allowing you to earn more.
How to choose?
The main criteria in choosing an electric screwdriver are budget, purpose and intended frequency of use. Once you have determined these points, you will understand which device is right for you.
When buying a Vortex electric screwdriver in a case, two batteries are always included
Brush-type electric screwdriver can work very long and regularly, but when really high loads and continuous work (especially for professional purposes), it is worth paying attention to the brushless version.
You can find the entire assortment of brush-type and brushless screwdrivers in our catalog. “Vihr”. the leaders of the power tool market in Russia according to the 2020 study of the Association of Trading Companies and Manufacturers of Power Tools.
The electric motor is a relatively simple device, which has a long service life under optimal loading conditions. It is the control element (collector or inverter) that is the weakest part, subject to wear and tear. Brush node is simple and cheap, so it is difficult to break it prematurely, while transistors can be damaged in corrosive environments. But, on the other hand, the “sticking” of the rotor under overload (when there is not enough power to rotate it, and the ratchet does not work or is blocked) can lead to burnout of the winding. In such a situation, a good quality electronic unit is able to cut off the current supply. So it’s hard to say which is better in terms of reliability.
With the device of the brushless motor have already been dealt with, and now it is worth considering the positive and negative sides of such tools.
There are several advantages of these motors
- They do not have the same problems as the brush models. They are more resistant to wear and tear, as the brushes do not give internal friction. Fire rate is also lower. No sparking allows operation in the most difficult conditions.
- Easier torque control. The number of levels (15), allows you to choose immediately the desired mode and just press the button. They have higher efficiency level.
- Economical in terms of electricity consumption. This is especially true. If the engine is battery operated. The tool can work on any material.
Important! Brushless motors can also deliver their maximum performance almost immediately.
Disadvantages of modern equipment
Theoretical advantages are fully realized in practice. This is something to consider when choosing a brush-type or brushless electric screwdriver.
Specialists note that such a tool:
- Much lighter and smaller in size. Compact size makes it possible to work in hard places and carry even in a normal bag.
- powerful and efficient in electricity consumption. The modern principle of motor operation, based on the use of electronics, increases user characteristics.
- Cordless brushless models operate for a long time on a single charge. Compared to conventional motors, it is up to 30 percent more efficient.
- Requires no additional cooling and no breaks in operation thanks to low heat generation.
- Doesn’t make too much noise when running, no sudden jerks.
- No sparks. It allows you to work in difficult conditions near fuel tanks, gas appliances.
- Easy to maintain. No need to buy and match brushes.
- It breaks down less often, as the absence of a brush allows you to work even under high loads, without the fear of clogging the engine.
The advantages of brushless motors in theory
The device of the brushless motor has already been dealt with, and now it is worth considering the positive and negative aspects of such tools.
There are several advantages of such motors:
- They don’t have the problems that brush models have. They are more resistant to wear and tear because the brushes do not produce internal friction. The fire rate is also lower. The absence of sparking allows operation in the harshest conditions.
- Simpler torque control system. 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 in terms of energy consumption. This is particularly important. If the motor is cordless. The tool can work on any material.
Important! Furthermore, brushless motors can deliver their maximum torque output almost immediately.
Advantages and disadvantages of a brushless power tool
The advantages of brushless screwdrivers are the following qualities:
- Easy speed adjustment. Variable torque over a wide range.
- No brush-collector unit. This has prevented the occurrence of faults associated with it and facilitated maintenance of the tool.
- Good tolerance of short-term torque overloads.
- Economical power consumption. Brushless motors have an efficiency of about 90%.
- Longer MTBF than tools with CSC.
- No electric sparking and therefore safe working in explosive gas mixtures.
- Small size and weight.
- Models with reversing feature the same power in both directions of rotation.
- No fall in rpm with an increased load on the chuck.
Only one disadvantage of these tools is noticeable. They are slightly more expensive than their collector-based counterparts.
Brush type electric screwdriver
Brush type motors. time-tested technology. On the side of this tool. small size, affordable price, long service life.
Construction and operating principle
Another name for a brush motor is the collector motor. It consists of:
The rotor is wrapped in copper wire. Current creates a magnetic field around the winding, which converts electricity into mechanical energy. This sets the armature in motion.
The task of the commutator (collector) is to switch the voltage from one winding to another and, accordingly, change the direction of rotation of the armature. To carry the current 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 current. It also changes the magnetic field so that the armature can continue to rotate.
The rotor with collectors and brushes is located inside the stationary stator. It also has another coil with a winding or a permanent magnet. This element produces a magnetic field that is reversed in the rotor 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.
- Easy to repair. If the brushes fail, you only need to replace them instead of buying additional parts or a whole new motor.
- Small size, easy to transport.
- Low efficiency of up to 60%. A lot of energy is expended on creating friction between the brushes and the collector.
- The graphite brushes are subject to wear and tear very quickly because of this. They should be replaced every 2-3 years. In addition, the graphite clogs the collector and can cause the electric screwdriver to malfunction.
- Brush tools are not capable of generating more than 3,000 rpm. For home use it is enough, but for more complicated tasks brushless models look preferable.
- Friction between brushes and commutator creates sparks. That is why you should work with the tool only in places where there is no risk of fire, away from flammable substances. Also check that the tool does not overheat as a result of friction and give it a “cooling off period”.
Brushless electric screwdriver
Tools without brushes and collector have been on the market since this century. Compared to a brushless electric screwdriver, brushless screwdrivers have greater efficiency, smaller size, longer life.
Design and principle of operation
In a brushless electric screwdriver motor, there is no collector and no brush assembly. All work is entrusted to an electronic control system.
The very principle of operation of a brushless electric screwdriver motor makes wear and tear very unlikely and ensures greater productivity. The key difference between this unit and the collector unit:
- The magnet of the motor is much smaller and lighter.
- Rotation is created by voltage, not centrifugal force.
- There is no coil on the motor armature, but it is the magnets inside the housing that create the magnetic field.
- Sensors on the control board figure out by themselves when to apply current. They work by a potential difference, like the Hall effect. The system reads all pulses and generates Pulse Width Modulation (PWM) signals. They are transmitted to inverters whose job is to increase the current they produce. Around the stator is a magnetic field and begins to interact with the field around the rotor. This sets the motor armature in motion.
Pros and Cons
- Efficiency reaches 90%, which is one and a half times higher than that of a collector device. No unnecessary energy is wasted on friction and spark formation.
- The motor quickly reaches the required rotation speed.
- The control system protects the brushless motor from overheating, which is undesirable in an electric screwdriver. This is not the case with collector tools.
- The battery lasts about twice as long as its brush-based counterpart.
- No sparking allows working in a fire-hazardous area.
- This electric screwdriver is quieter than a collector screwdriver.
- Smaller size, lighter weight.
- High price. It is the “merit” of the motor control system.
- Difficulty in replacing parts. If the trigger, for example, fails, then you have to buy the control board and the motor stator with it. these 3 parts are sold in one set. It costs up to 75% of a new electric screwdriver. After the warranty expires, it makes no sense to repair the tool.
Electric electric screwdriver: advantages of the device and disadvantages
220 Volt screwdriver: what to look for when choosing?
To choose a conventional device for long and comfortable work, it must have:
Collector vs. brushless: summary table
Now. a comparative characteristic of the two types of tools in the form of a table with key parameters.
|Characteristics||Type of electric screwdriver|
|EFFICIENCY||up to 60%||90%|
|Wear and tear||faster||longer|
|Battery life||less||lasts almost twice as long|
|Working in a fire hazardous environment||high risk||safe|
Which tool to choose?
Looking at the table above, you can come to an unambiguous conclusion: brushless screwdrivers win, as they say, one-way. Almost all characteristics are in their favor, and only a few parameters make the collector tool look preferable.
However, this is on paper. Brushless equipment is better, more modern, but for this superiority will have to pay well. Before laying out a solid amount, it is worth answering yourself a few questions:
No need to spend a lot of money on a brushless electric screwdriver, which will be needed only a couple of times, and the rest of the time will gather dust in the closet.
For home work, a brush tool is enough
One of the main points with which you should choose the type of tool is the possibility of repair. Even if we exclude the obligatory replacement of brushes every couple of years, the collector unit will most likely leave the LADA already when the money paid will have been worked off in full. It’s not a shame to throw out your old tool and buy a new one for the same money.
Conclusion! If an electric screwdriver is only needed for occasional, localized jobs around the house, a collector tool will suffice. But replacing one part in a brushless electric screwdriver will entail buying several more (otherwise. nothing), which will make up from half to 75% of the price of a new device. It will probably last longer than a brush saw, but if it breaks, there’s no point in repairing it.
The three main criteria in choosing the type of electric screwdriver are budget, purpose, and planned frequency of use. And you can see the difference in performance between a collector tool and a brush tool here: