Why does the stepping motor of the advertising engraving machine get hot?
1. For all kinds of stepper motors, the interior is composed of iron core and winding coil. The winding has resistance, and power will generate loss, which is proportional to the square of the resistance and current. This is what we often call copper meteorite. If the current is not a standard DC or sine wave, harmonic loss will also occur; the iron core has hysteresis The eddy current effect also produces loss in the alternating magnetic field, and its size is related to material, current, frequency, and voltage, which is called iron loss. Both copper loss and iron loss will be manifested in the form of heat, which will affect the efficiency of the motor. Stepper motors generally pursue positioning accuracy and torque output. The efficiency is relatively low, the current is generally relatively large, and the harmonic content is high. AC motors are serious.
2. The reasonable range of stepping motor heating The allowable degree of motor heating mainly depends on the internal insulation level of the motor. The internal insulation performance will be destroyed at high temperature (above 130 degrees). So as long as the inside does not exceed 130 degrees, the motor will not be damaged, and at this time the surface temperature will be below 90 degrees. Therefore, it is normal for the surface temperature of the stepper motor to be 70-80 degrees. The simple temperature measurement method is useful with a spot thermometer, and it can also be roughly judged: you can touch it with your hands for more than 1-2 seconds, and it does not exceed 60 degrees; you can only touch it with your hands, about 70-80 degrees; , then more than 90 degrees.
3. Heating of the stepping motor changes with the speed. When the constant current drive technology is used, the current of the stepping motor will remain relatively constant at static and low speeds to maintain constant torque output. When the speed is high to a certain extent, the internal counter electromotive force of the motor will increase, the current will gradually decrease, and the torque will also decrease. Therefore, the heat generation caused by copper loss is related to the speed. Generally, the heat is high at static and low speed, and the heat is low at high speed. However, the change of iron loss (although it accounts for a small proportion) is not always the case, and the entire heat generation of the motor is the sum of the two, so the above is only a general situation.
4. Although the heating of the motor generally does not affect the life of the motor, it is unnecessary for most customers. However, severe fever can come with some negative side effects. For example, the different thermal expansion coefficients of various parts inside the motor lead to changes in structural stress and small changes in the internal air gap, which will affect the dynamic response of the motor, and it will easily lose synchronization at high speeds. Another example is that some occasions do not allow excessive heating of the motor, such as medical equipment and high-precision testing equipment. Therefore, the heating of the advertising engraving machine motor should be controlled as necessary.
