Polymer resettable fuse inspection of electrical aging
The influence of the electrical aging process of the resettable fuse on the electrical performance such as current resistance, voltage resistance, and lightning resistance;
Among them, 220 V electrical aging conditions are the best.
From the perspective of overcurrent protection, the resistance change of polymer PTC materials is the main indicator of the stability of its electrical properties. The resistance value rises after energization and aging. This is because during aging, the polymer PTC material increases its own temperature due to Joule heat, until the disconnection temperature, the polymer PTC material is in a high resistance state. After the current resistance test, the unaging resistance value changes the most. After the current resistance test, the resistance value does not change much, although the resistance value is relatively stable despite repeated current shocks. It shows that after the aging effect of a strong electric field, the polymer PTC material is very stable in structure, which is also the purpose of electrical aging. Electrical aging improves the pressure resistance of polymer PTC materials. The pressure resistance performance continues to improve with the strengthening of aging conditions.
There are two reasons:
1. After aging, the internal conductive channels are "smooth". After further application of the electric field, although the resistance value changes, the change is smaller than that of the unaged one;
2, Through aging, the polyethylene in the polymer PTC material is polarized. In this way, the polyethylene and the conductive material conductive carbon black are more closely combined, and the overall material structure is more stable, thereby improving its pressure resistance.
Electric aging method:
Method 1: Power on according to product model and working current;
Method 2: Directly power on 220 V and stop for 1 min;
Method 3: Power on 100 V and stop for 2 s, then increase to 220 V and stop for 1 min.
1) Thermal aging can make the conductive channels of polymer PTC materials more substantial and stable, and the resistance distribution more balanced.
(2) Electrical aging can improve the current resistance, voltage resistance, and lightning resistance performance of polymer PTC materials, and 220 V electrical aging conditions are the best.
(3) In the actual use process, the polymer PTC material must undergo thermal aging, and the electrical aging depends on the performance requirements of the use occasion.