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15kV Drop-Out Fuse Cutout - Reliable Short-Circuit Protection for 10kV Distribution by China Suppliers and Factory
Working Principle
The moving contacts at both ends of the fuse tube are fastened by the fuse (melting element). After pushing the upper moving contact into the protruding part of the "duckbill", the upper static contact made of phosphor copper sheet etc. presses against the upper moving contact, so that the fuse tube is firmly clamped in the "duckbill". When the short-circuit current passes through and fuses the fuse, an electric arc is generated. The steel paper tube lined inside the fuse tube produces a large amount of gas under the action of the electric arc. Since the upper end of the fuse tube is sealed, the gas is sprayed downward to extinguish the electric arc. Due to the fuse melting, the upper and lower moving contacts of the fuse tube lose the tension of the fuse. Under the action of the fuse tube's own gravity and the spring sheets of the upper and lower static contacts, the fuse tube falls rapidly, disconnecting the circuit and cutting off the faulty line section or faulty equipment.
Applicable Environment
The 10kV drop-out fuse is suitable for outdoor places where the ambient air is free of conductive dust, corrosive gases, flammable, explosive and other hazardous environments, and the annual temperature difference ratio is within ±40℃. Its selection is based on two parameters: rated voltage and rated current, that is, the rated voltage of the fuse must match the rated voltage of the protected equipment (line).
Installation Tips
- 1 During installation, the melting element should be tightened (so that the melting element is subjected to a tension of about 24.5N), otherwise it is easy to cause contact heating.
- 2 The fuse should be firmly installed on the crossarm (frame) without any shaking or wobbling.
- 3 The fuse tube should have a downward inclination angle of 25°±2° to facilitate the rapid fall of the fuse tube by its own weight when the melting element fuses.
- 4 The fuse should be installed on a crossarm (frame) with a vertical distance of not less than 4m from the ground. If installed above the distribution transformer, it should maintain a horizontal distance of more than 0.5m from the outermost contour boundary of the distribution transformer to prevent other accidents caused by the falling of the fuse tube.
- 5 The length of the fuse tube should be adjusted appropriately. It is required that after closing, the duckbill tongue can hold more than two-thirds of the contact length to avoid accidental self-falling during operation. The fuse tube should not push the duckbill to death to prevent the fuse tube from failing to fall in time after the melting element fuses.
- 6 The melting element used must be a standard product from regular manufacturers and have a certain mechanical strength. Generally, the melting element is required to withstand a tension of at least 147N.
- 7 The 10kV drop-out fuse is installed outdoors, requiring a phase-to-phase distance greater than 70cm.
Frequently Asked Questions
Q How does a 10kV drop-out fuse extinguish the electric arc?
A When the fuse melts due to a short-circuit current, the steel paper tube inside the fuse tube generates a large amount of gas under the arc's heat. Since the upper end of the fuse tube is sealed, this gas is forced downward, effectively blowing out and extinguishing the electric arc.
Q What environments are 10kV drop-out fuses suitable for?
A They are designed for outdoor use in environments free from conductive dust, corrosive gases, and flammable or explosive hazards, with an annual temperature difference within ±40℃.
Q What is the correct inclination angle for installing the fuse tube?
A The fuse tube must be installed at a downward inclination angle of 25°±2°. This angle ensures that the fuse tube drops quickly under its own weight once the melting element fuses, reliably disconnecting the circuit.
Q What tension should the melting element withstand during installation?
A During installation, the melting element should be tightened to a tension of approximately 24.5N. Additionally, standard melting elements from qualified manufacturers should be used, capable of withstanding at least 147N of mechanical tension during normal operation.
Q What is the minimum installation height above the ground?
A The fuse must be mounted on a crossarm or frame at a vertical height of no less than 4 meters from the ground. When installed above a distribution transformer, it must also maintain a horizontal clearance of more than 0.5m from the transformer's outermost boundary.
Q How should the fuse tube length be adjusted to prevent accidental self-falling?
A The fuse tube length should be set so that after closing, the duckbill tongue securely holds more than two-thirds of the contact length. However, the tube must not be pushed so tightly that it prevents the tube from falling when the melting element fuses.
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