Requirements of stepping motor on Temperature

For stepper motor specification, the operating temperature range for stepper motor should be 0～50℃ while humidity should be 20%～90%RH, and storage temperature should be -20～70℃ while humidity should be 15%～95%RH. Now, environmental requirements for stepper motor usage are as follows: Requirements on Temperature: The standard of stepper motor insulation material is grade UL B, which indicates that heat resistance of motor insulation system is within 130℃. In consideration of motor temperature difference between inside and outside and safety coefficient, the surface temperature of motor is required below 100℃. In consideration of the normal room temperature within 40℃, temperature rise of motor coil should be controlled within 80K. If the temperature of motor coil is beyond the limit value of insulation system, the elements in it, such as enameled wire of motor coil, insulation slot, PCB board, etc. may be burnt out easily, resulting in motor failure (generally, open circuit occurs, sometimes, short circuit also occur). re realistic selection is to control the temperature rise of motor, which is to achieve the aim by strengthening the heat dissipation conditions or reducing the operating current of motor. The condition that the temperature of stepper motor is too high will not only affect the safety of insulation system, but also affect the stability of permanent magnet. The permanent magnet will be demagnetized as the temperature rises, reducing the working torque. Requirements on Humidity: The nema 17 stepper motor should meet the humidity requirements, which is mainly to avoid the condensation in motor. Silicon steel plates on rotor outer surface and stator inner surface of stepper motor has no other anti-rust measures except anti-rust oil application during processing. If the humidity is too high, condensation occurs easily on surface, causing rust. Because the clearance between rotor and stator of stepper motor is very small, the rusty spots may make rotor be seized, resulting in motor failure. On the other hand, the condition that humidity is too high can also affect the insulation characteristic of insulation material, which has little effect on small size stepper motor whose normal operating voltage is very low while has noticeable influence on those stepper motor whose drive voltage is high.