Comparison of advantages and disadvantages of brushless motor and brush motor
A) "brushless" brush "basic concepts: widely used electric bicycle is a permanent magnet DC motor, DC permanent magnet motor according to whether use the brush can be divided into brushless motor and brushless motor two, brush motor is the mainstream product of DC motor, the vast majority of electric bicycle motor is a brushless motor. Brushless motor is a DC motor special, it uses a built-in sensor and method of electronic commutator for electronic commutation of brushless motor, the main purpose is to eliminate the brush wear, and the noise generated by the brush contact.
Two) brush motor faults did not become restraints it is widely used in the electric bicycle: brush wear and noise of the motor is "brush" and "two major drawbacks of brushless", but in spite of these two disadvantages, why the vast majority of domestic brand manufacturers are still using the brush motor the scheme, are they not aware of this problem? The reason lies in:
A) brush wear does not constitute a major problem of electric bicycle is a kind of intermittent working vehicle, a battery discharge time is usually the longest (riding time) is generally 2-3 hours, the average time of users use every day trade is about 1-2 hours, and now, the disc rotor motor is widely used in electric bicycle by using the plane commutator and brush type quality extended working life, usually within 1500 hours or more, therefore, calculated according to the average user every day for 1.5 hours, a set of brushes using time for up to 1000 days. As can be seen, a set of qualified brush service time is close to three years, and the replacement of a group of brush costs only about 5 yuan, an average of less than 2 yuan per year! What's more, the use of electric bicycles for 3 years is really necessary to do some comprehensive vehicle inspection and maintenance, replacement of some parts wear, promote trade ten years of maintenance free motor exaggerated this point of view, there is suspicion of misleading consumers.
B) motor noise is normal I visited the market, a brushless motor of electric vehicle sales, to demonstrate characteristics of mute brushless motor under no-load condition, in order to prove the brushless motor than the brush motor is much superior to that in fact, the purchase of electric vehicles is not to buy air conditioning equipment, consumers need not it is no noise and make a decision whether or not to buy. In fact, the use of a brushless motor of electric vehicle users will know, brushless motor in no-load or low load (such as flat without wind) motor sound is very small, but when running to the heavy load such as uphill, against the wind, it tends to be a far more than brush motor "huge" the sound, even electromagnetic shaking uncomfortable, but the sound is not in the promotion process in quiet. In fact, the vehicle motor running a sound is normal, after all, it is a kind of outdoor use of transport, the provisions of the state standard for noise less than 62 decibels, the vast majority of domestic brush motor can be controlled in decibels below 55 dB, is a qualified product. Brushless motor sales guide consumers to pursue the "mute", to promote electric vehicle promotion like air conditioners, also suspected of misleading consumers, air-conditioning noise affect sleep, while the electric car noise will not affect the use of the!
Three) without a series of problems of the existing motor scheme: an evening "brushless brush" wins the arbitrary will brush motor accused of "short life, large noise, low efficiency, even pointed out that" the general use of 6 months to a year to replace the carbon brush motor. "The voice of Crusade without fear! For this reason, this article also does some research on the disadvantages of brushless motor for electric bicycle.
(A) poor working conditions of sensors lead to system failure! Normal brushless motor design is generally set photoelectric or magnetic in non heat source region (Holzer element) sensor for detecting the rotation of the motor position signal control, and now sold most of the so-called brushless motor wheel electric bicycle, by design size and installation restrictions, can not the sensor and heat isolation, almost always used in the stator core slot and positioning to install sensors, with the method of fixed three Holzer components of the motor heat glue as everyone knows, is an objective existence, it comes from the motor copper loss and iron loss, especially when the motor works in low efficiency area, heat accumulation the speed is very fast, so the core will be fever, direct sensing elements arranged in the heat zone will drift performance, lead to commutation error, once the wrong direction The mistake will lead to a big drop in the efficiency of the motor and a further increase in the temperature, which leads to a vicious cycle, which directly results in the burning of the electronic commutator, which is generally manifested as a short circuit". Once the "short circuit", the brushless motor has a "stuck" feeling, the rotation is very difficult, users can not even ride on foot. Please only tricycle or taxi back, experienced users will own a pair of scissors, once the short circuit card die, the motor input line cut, the "open", so, the burned "brushless", you can return to the maintenance department.
B) induction electromotive force, resulting in burning: the controller to the identity of the customer visit in the market, there is a brush salesman, after I proudly presents the "silent" characteristics, and to demonstrate the self charging function in the best of spirits of brush motor Magic: turn off the power supply, rocking axis, turn the rear wheels then, said the unit has been sent