Stepper motor as a digital actuators, widely used in the motion control system. Many users friends when using stepper motor, sensory motor work with larger fever, suspicious, I do not know this kind of phenomenon is normal. Fever is actually a common phenomenon of stepper motor, but how the degree of fever is normal, and how to minimize the stepper motor fever General electrical engineer pointed out that first of all, to understand why stepper motor fever For a variety of stepper motor, the internal is composed of iron core and the windings. Winding resistance, electricity will produce loss, the loss is proportional to the square of the size and the resistance and current, this is the copper loss, we often say that if the current is not a standard dc or sine wave, will also produce harmonic loss; Core has hysteresis eddy current effect, also can produce loss in the alternating magnetic field, its size and material, current, frequency, voltage, this is called iron losses. Copper loss and iron loss will be displayed in the form of heat, which affects the efficiency of the machine. Stepper motor general pursuit of position precision and torque output, the efficiency is low, the current is compared commonly big, high harmonic components, the frequency of the alternating current is also change with speed, thus stepping motor are widespread fever, than the general ac motor serious condition. Moreover, to control the step motor heating within a reasonable range Electric heating allows to what extent, depends on motor internal insulation class. Internal insulation performance at high temperatures (130 degrees) will be destroyed. So as long as within no more than 130 degrees, the motor will not damage, while the surface temperature under 90 degrees. So, step motor surface temperature in 70-70 degrees are normal. Simple useful point thermometers, temperature measurement method can also be rough judgment: by hand can touch more than 1 to motor part 2 seconds, no more than 60 degrees; Only with the hand touch, about 70-80 degrees; Drop a few drops of water gasification rapidly, more than 90 degrees; , of course, also can be used to detect temperature gun. Third, the stepper motor heat change with speed Using constant current drive technology, stepping motor under static and low speed, the current will remain relatively constant, to maintain a constant torque output. High speed to a certain extent, the motor internal counter potential, current will gradually decrease, the moment will decline. Therefore, because of the copper loss of fever is related to the speed of the story. Generally high fever when static and low speed, high speed low fever. But the iron losses (smaller) while the percentage of change is not at all, and motor of the fever is the sum of the two, electrical engineer pointed out that the above is just normally. Fourth, the effects of fever Motor heat while generally will not affect the life of the motor, for most customers don't need to ignore. However, serious fever can bring some asynchronous motor negative impacts. Internal parts such as motor thermal expansion coefficient of different lead to the change of structural stress and internal air gap of tiny change, affects the dynamic response of the motor, high speed will be easy to out of step. And as some situation does not allow excessive heating of the motor, such as medical equipment and high-precision test equipment, etc. So the control of the heating of the motor should be necessary. Finally, reduce the heating of the motor To reduce fever, is to reduce the copper loss and iron loss. Reduce copper loss, there are two directions, resistance and current, choose as far as possible when this request in the selection of small resistance and the rated current of the motor, the two-phase motor, motor without parallel in tandem. But this often conflict with the moment and the requirement of high speed. For motor has been selected, should make full use of the drive of automatic flow control function and offline function, the former automatically reduce current when motor is static, the latter will be the current be cut altogether. In addition, the subdivision driver due to the current waveform is close to sine, less harmonic, electric heating will be less. Reduce iron loss method, related voltage level, although will bring high speed characteristics of high pressure driven motor, but also brings the increase of the heat. So should choose the appropriate drive voltage grade, www.facebook.com/dongfeng.motor recommend suite, give attention to two or morethings stationarity and fever, noise, etc.
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