Structural Changes Of Fuse Tube Under Gravitational Moment

In the power distribution system structure, the mechanical structure of drop out fuse not only undertakes the task of conducting electricity, but also needs to withstand the combined effects of its own weight, tension and electrodynamic force. In operation, the fuse tube is typically suspended or installed at an angle. When the structure is affected by gravitational torque, corresponding mechanical changes occur in the internal components and contact points. For outdoor or drop-out fuses, this torque effect is directly related to the fuse tube's operating structure. The fuse tube is connected to the support via the contacts. After the fusible element melts, it undergoes mechanical displacement under gravity, forming a visible fracture.

Characteristics of Fuse Tube Movement Caused by Gravitational Torque

In the fuse's operating structure, the fuse tube exhibits certain mechanical behaviors driven by gravitational torque. These changes are related to the contact structure, fulcrum position, and mass distribution.

Specific manifestations include:

• Rotational Displacement: The fuse tube rotates around the lower contact or hinge point, forming a clear mechanical breaking path.

• Contact Separation: After the contact pressure disappears, the fuse tube deflects, causing the conductive contacts to quickly separate.

• Air gap formation: The fuse tube swings down, creating an air gap that provides space for the arc to lengthen and extinguish.

• Change in structural stability: The fuse tube, originally in the closed position, enters a suspended or dropped state, resulting in a redistribution of structural forces.

This mechanical action, driven by gravitational torque, causes a significant structural change in the fuse after a fault current occurs. The change in fuse tube position not only reflects the operating state of the equipment but also demonstrates the mechanical synergy in the structural design of electrical protection devices.