The matching principle of the insulation grade of the three phase asynchronous electric motor with the usage environment is mainly reflected in that the selection of the insulation grade should be comprehensively considered based on factors such as the usage environment, working conditions, rated voltage and rated power.
1. Definition and classification of insulation grades
The insulation grade reflects the withstand voltage capacity and performance of the motor insulation material, which is usually represented by letters such as A, B, F, H, etc., among which grade A is the lowest and grade H is the highest. Different insulation classes correspond to different temperature resistance capabilities. For instance, the maximum allowable temperature for Class B insulation is 130℃, for Class F it is 155℃, and for Class H it is 180℃.
2. The matching principle between insulation grade and usage environment
- Ambient temperature: In high-temperature or humid environments, motors with higher insulation grades should be selected to extend their service life. For instance, H-class insulation is suitable for high-temperature environments (such as metallurgical sites). The higher the ambient temperature, the higher the requirement for insulation grade.
- Working conditions: In equipment operating at high load and full load for long periods, motors with high insulation grades should be given priority.
- Environmental humidity and protection grade: In dusty or humid environments, choosing motors with a high protection grade (such as IP55) can effectively prevent external factors from eroding the internal components of the motor.
- Altitude and temperature rise: Altitude and ambient temperature have an impact on insulation grade. For instance, when the altitude exceeds 1000m or the ambient temperature exceeds 40℃, the insulation grade should be adjusted in accordance with the provisions of GB 755.
3. Specific application cases
-YE3 series motors: Their insulation class is B (155℃), suitable for ambient temperatures ranging from -20℃ to +40℃, with an altitude not exceeding 1000m.
-IE3 series motors: Insulation class F, suitable for ambient temperatures ranging from -15℃ to 40℃, with an altitude not exceeding 1000m.
-YZR series motors: Insulation class is F or H, suitable for places where the ambient temperature does not exceed 40℃ or 60℃.
-K series motors: With F-class insulation grade, they are suitable for general locations where the ambient temperature does not exceed 40℃.
4. The relationship between Insulation grade and temperature rise
The insulation grade not only affects the temperature resistance capacity of the motor, but also influences its temperature rise limit. For instance, the temperature rise limit of F-class insulation is 105K, and that of H-class is 125K. A higher insulation grade helps to extend the service life and improve reliability.
5. Summary of Matching principles
- Environmental adaptability: Select the appropriate insulation grade based on environmental conditions such as temperature, humidity, and altitude.
- Load and Lifespan: In high-load or high-temperature environments, select motors with high insulation grades to extend their service life.
- Standards and Specifications: Comply with national standards such as GB 755, and adjust the insulation grade according to specific usage conditions.
Conclusion
The matching principle of the insulation class of the three phase asynchronous electric motor with the usage environment should comprehensively consider factors such as environmental temperature, humidity, load conditions, and altitude, and select the appropriate insulation class (such as F class, H class) to ensure the safe operation and service life of the motor. At the same time, relevant standards and norms should be followed to ensure the stable operation of the motor under various working conditions.
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