What is the maximum permissible temperature of the stepper motor?
Third, the stepper motor heating varies with speedWhen the constant current drive technology is adopted, the current of the stepping motor will keep relatively constant at the static and low speed, so as to keep the constant torque output. When the speed is high to a certain extent, the back emf will rise, the current will decrease gradually, and the torque will decrease. Therefore, the heat caused by copper loss is related to the speed. Static and low speed, generally high fever, low fever at high speed. But the iron loss (although the proportion of smaller) changes in the situation is not entirely, and the whole motor heating is the sum of the two, so the above is only general.
Moreover, the heating of the stepping motor is controlled in a reasonable rangeThe extent to which motor heating is allowed depends mainly on the internal insulation level of the motor. Internal insulation is destroyed at high temperatures (above 130 degrees). Therefore, as long as the internal is not more than 130 degrees, the motor will not damage, and then the surface temperature will be below 90 degrees. Therefore, the stepper motor surface temperature is normal at 70-80 degrees. A simple method for measuring temperature of useful point thermometer, also can judge roughly: hands can touch 1-2 seconds, not more than 60 degrees; hand can touch, at about 70-80 degrees; drop a few drops of water quickly gasified, above 90 degrees; of course, can also be used to detect temperature gun.
The maximum temperature that can be accepted depends on the quality of each brand. Under normal circumstances, 70-80 degrees Celsius is normal.First of all, to understand why the stepper motor heatingFor all kinds of stepper motors, the internal is composed of iron core and winding coil. Winding resistance, electricity will generate losses, losses and the size of the resistance and the current is proportional to the square, which is why we often say that the copper loss, if the current is not standard DC or sine wave will produce harmonic loss; core hysteresis effect of eddy current in the alternating magnetic field will also have a loss, its size and material, current the frequency, voltage, this is called iron loss. Copper loss and iron loss will be expressed in the form of heat, which will affect the efficiency of the motor. Stepper motor is the general pursuit of positioning accuracy and the torque output, the efficiency is relatively low, the current is relatively large, and the harmonic components of high frequency alternating current also increases with the speed change, thereby stepping motor universal presence of fever, and the situation is serious than the general AC motor.
Fourth, the effect of feverAlthough the heating of the motor will not affect the life of the motor, it is not necessary for most customers to pay attention to it. But serious fever can have some negative effects. If the thermal expansion coefficient of each part of the motor is different, the change of the structural stress and the small change of the internal air gap will affect the dynamic response of the motor, and the high speed will easily step out of step. In some cases, excessive heating of the motor is not allowed, such as medical instruments and high-precision testing equipment. Therefore, the motor heating should be necessary control.
