Stepper Motor Temperature aspect
On the temperature requirements:
Stepping motor insulation material standard is ULB level, which refers to the motor insulation system temperature within 130 °, taking into account the motor inside and outside the temperature difference and safety factor, so the motor surface temperature is less than 100 degrees. Taking into account the general temperature at room temperature within 40 °, so the requirements of the motor coil temperature control within 80K. If the motor coil temperature exceeds the temperature limit of the insulation system, it is easy to burn the motor coil enameled wire and insulation box, PCB board and other insulation systems, resulting in motor failure (usually open, but there are short circuit phenomenon).
The rated current of the motor is mainly based on the motor can withstand the heat to calculate it. If the working temperature of the motor is relatively high, it is necessary to consider reducing the motor operating current to reduce the temperature rise, and ultimately the internal heating control of the insulation system can withstand the range. For example, if the ambient temperature is 60 °, the motor temperature will be controlled within 60K. Because the vast majority of stepper motor manufacturers are insulating materials B-class standard, a higher level of insulation material is almost impossible to correspond or cost is too high, so the work environment temperature is relatively high applications, the more realistic choice is to control The temperature rise of the motor, that is, to strengthen the cooling conditions or reduce the motor current to achieve.
Stepping motor temperature is too high, in addition to the safety of the insulation system, but also affect the stability of permanent magnets. Permanent magnet with the temperature rise will demagnetization, thereby reducing the motor torque. Stepper motor magnets within 130 ° of the demagnetization factor can be ignored, but some manufacturers of magnet even in the insulation system can bear the problem, there have been significant torque attenuation problem.
Stepper motor temperature is too low, will allow the bearing grease solidification, thus losing the bearing lubrication, so less than 0 degrees to consider the case of choice of low temperature bearings. If the customer in the motor before the first power to let the motor heat up to reach the motor requirements of the working temperature and then let the motor rotation is acceptable, but the device startup process to be set accordingly.