The physical pair of patented fasteners and ordinary bolts that can solve the problem of overheating of electrical contacts are shown. Compared with ordinary bolts, the patented fasteners have been optimized with optimization techniques and have the following advantages.
(1) Increase the bolt head and nut, thereby increasing the effective force receiving area of ​​the fastening electrical contact and increasing the effective current carrying cross-sectional area of ​​the electrical contact contact surface. 1 is the comparison of the effective current-carrying cross-sectional area between the patented fastener and the ordinary bolt. It can be seen that the patented fastener has obvious advantages in the current-carrying cross-sectional area.
(2) The concave surface of the bolt head and the nut receiving surface is slightly concave, and the force receiving surface is not a flat surface, but has a certain inclination from the inner edge to the outer edge. When the contact is fastened with a patented fastener, the outer edge of the nut is firstly stressed, and the inner force is relatively smaller than the outer side. The pre-pressure applied to the electrical contact can effectively overcome the outer edge of the electrical contact during online operation. The anti-warping force increases the fatigue resistance of the electrical contacts, especially the impact of the short-circuit current, and the dynamic stability performance is good, avoiding the overheating accident caused by the looseness of the contacts.
Thickened the nut. The increase of the nut thread increases the torque force of the nut and the screw, and the electrical contact is subjected to greater pressure, which reduces the contact resistance of the contact, improves the dynamic stability of the contact, and enhances the fatigue resistance of the electrical contact. ability. Remove the spring pad and use a nut to prevent loosening.
Test and actual operation of the electrical contact temperature rise test We have a temperature rise comparison test of the patented fastener and the ordinary bolt fastening electrical contact, as shown. Two electrical contacts made of aluminum rows connected with the same specification of the patented fastener A and the ordinary bolt B are strung together, and a certain current is used to simulate the operation of the actual electrical contact, and the two electrical contacts are all in the same Ambient temperature and heat dissipation conditions. In order to prevent the heat transfer of the two electrical contacts from affecting the test results, the test piece is placed in the oil medium. After a period of flow, the temperature changes at the two electrical contacts are measured.
Conclusion test and long-term actual online operation, the patented fastener can effectively avoid the overheating problem of ordinary bolt-tight electrical contacts, and has certain advantages for improving the safety production and economic benefits of the power system.
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