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The advantage and disadvantage of Brushless tool or Brush tool
- Aug 17, 2018 -

The progress of the tool industry is really slow. Until now, there is no universal popularity. There are still many people who have never heard of the four-axis six-axis fixed-wing helicopter flying in the sky. Basically all brushless motors are not brushless motors. I am really embarrassed to take out and play with domestic brushless motors and ESCs are very mature. The price is already close to the cost of universal popularity. Look at the electric bikes on other roads. The advanced ones are DC brushless motor. The computer industry has long popularized the hard disk drive in the computer. All the fans are DC brushless motor. The life of the DC brushless motor has been abnormal. Recently, the electric fans in the home have been replaced with DC brushless motors. Infinitely adjustable speed power failure, you can also directly use the battery

It seems that this is the future of electric motors.

Many people who have not touched a brushless motor will ask why there is no advantage in brushless.

Let me briefly talk about the advantages and disadvantages of brushless


1 The biggest advantage of brushless is the torque.

    

Everyone says that the brushless torque is small. This is how many people talk with colored glasses. If you use it yourself, you will find that the torque of the brushless tool is very large. Many times, the most obvious place beyond the brush tool is the output torque at low speed, such as electric drill. Brushed electric drills have a torque of less than 30%. There is almost no torque. 30% to 50% of the torque is less than one-third of the maximum torque. Only when the speed is high, will it work normally. The torque of this point is brushless electric drill. The brushless electric drill has no torque. The output torque is almost constant. The low speed also has a huge output torque. Even 5 percent of the rotational speed is more than 70%. Say the maximum torque, we know that the output shaft torque depends not only on the motor but also how many stages of reduction gear brushless motor. Because there is no wear resistance and no wear life, the speed can be made very high without reducing the output shaft speed. You can add one or two stages of reduction gears, which will greatly increase the loss. Torque can beat any resistance to heat and abrasion brush motor brush motor carbon brushes output can not high speed without a solution


2 Everyone likes another advantage. It is power saving.

    

      The brushless motor has no carbon brush rotor and is completely free to rotate without any frictional resistance. Moreover, the computer can accurately control the rotation angle of the rotor without wasting a little energy. Therefore, the power saving of many brushless tools is very large. Hundreds of watts seem to be very expensive, but in actual use, you will find that the battery is very useful. The benefit of the brushed impact drill is no more than seven amps per ampere. The top-grade brushless impact drill is empty. More personally, I feel that the light and lively small battery life is at least four times to five times longer. The heavy work is also twice the use time of the brush tool. However, the brushless angle grinder is very expensive. The use time is very short, ten minutes, no electricity, I don’t know if there is a brush, the angle grind is more expensive, no other brushless tools are better than the brush saver. The used person has obvious feeling electric drill hammer I don’t know how to save electricity. I don’t know if the brushless circular saw is a power-saving comparison. There is no comparison too afraid to talk nonsense


3 Another advantage is the speed

    

      Because there is no carbon brush rotor completely free to rotate without frictional resistance and no carbon brush wear, so the speed can be done very high 35,000 or even 100,000 is possible, but high speed is not a brushless advantage. The advantage of brushless is accurate. The rotor of the control speed brushless motor is equipped with an angle sensing magnet. There are three Hall sensors behind the rotor. The amplitude and speed of the rotor can be monitored every moment. This detection is very accurate. He determines the energization timing and energizing current of the stator coil. If the tool is dry and the rotor speed is reduced, the angle will be incorrect. The computer will give the stator coil a higher voltage and a larger current to ensure that the rotor speed will not decrease. This is why the brushless motor has a low torque when the motor rotates at a low speed. There will also be a very high voltage and a large current to generate a strong magnetic field to twist the rotor. When the brush motor has a low speed, the supply voltage is very low, there is no current, so there is no torque. This is destined to have the brush tool eliminated by the speed of the brushless tool. Accurate adjustment you want a hundred turns You want three hundred turns, you want a thousand turns, no problem, no more guarantees, no more idling, no work, no heavy changes, because it is a computer that detects and controls the speed.

     

4 If you want to say the next advantage, it is life.

    

     Brushless motor can be said to be the life of bearings and electronic circuits because of the lack of wear life. But I don’t know that many official propagandas say that the life is very long. I also removed some of the old foreign garbage brushless tools. The motor part is very good, but there is no wear but gears. Partly finished, everyone knows the tool of the gear machine, the shell switch, these have a long life, especially the gear, often dry and heavy, the reduction gear will wear very seriously, even if the life of the brushless motor tool will not be extended, I listen to one every day. The friend who works hard on the tool says that there are generally tools for brushing three or four times after the original carbon brush. The stator of the machine motor has gears to the limit. How to change the carbon brush is not the machine. This seems to be a brushless tool and Compared with the brush tool, the lifespan is extended by three times to four times. It is no longer the trouble of replacing the carbon brush. The gear will be the same as the motor before the motor. Of course, if you don’t work hard, it doesn’t matter. The life may not be the advantage of the brushless tool.


5 Suddenly think of an advantage. Radiation


     The spark generated between the brush motor carbon brush and the commutator is a strong source of electromagnetic radiation. I have seen a foreign test razor is your home's strongest battery radiation source is several times stronger than the mobile phone radiation. The radiation is also small, no brush, no spark, it should be a lot smaller.

     


Can't report good news and don't report worry

    

Disadvantages, there are still many disputes. Some people say that it is a shortcoming. Some people think it is not a fault. I will simply talk about it.


1 Maintenance is very difficult. The control circuit is complicated. There are single-chip control timing. Hall sensor is also needed to detect the angle of the motor rotor. The power supply voltage is detected. The battery temperature must be monitored in real time. There is a little abnormality, but it is because the protection circuit is compared. Perfect circuit part failure rate is very low, the circuit part of the factory is fully filled with glue, sealed, dustproof, moisture proof and waterproof.


2 Some people don't buy brushless and feel that brushless is too expensive. This is really a disadvantage. It is more expensive than the same grade brush. We have the omnipotent Taobao. The price of Dewei's top brushless impact drill has been very close to me. Tool enthusiasts do not hesitate to start with the low-cost brushless tools such as Miwoqi Richie Makita and other Taobao treasures believe that the price is not a barrier to the popularity of brushless.


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