JB 16-630mm² 70-230mm Overhead Cable Parallel groove clamp Wire Clamp
JB series aluminum parallel groove clamps are suitable for non-load-bearing connection of aluminum conductors and steel strands of overhead line power lines, and also used for jumper connection of non-linear poles and towers. It can be used together with an insulating cover for protection and insulation. This series of aluminum parallel groove clamps can be divided into JB-0, JB-1, JB-2, JB-3, JB-4... to meet different needs of power lines.
Parallel groove clamps are all non-load-bearing types, mainly including bolt type parallel groove clamps, H-type (or C type) parallel groove clamps and wedge-shaped parallel groove clamps. Among them, bolt type parallel groove clamps are further divided into three types. There are two types of equal-diameter parallel groove clamps and different diameter parallel groove clamps.
The meanings of the letters of the product model are:
J- connection, B- parallel groove, T- copper, L- aluminum
1. Use anti-oxidation aluminum alloy material.
2. Tooth structure, small contact resistance and reliable wiring.
3. The parts are connected together, and the parts will not be dropped during installation.
4. The arc is held tightly in a large area, and the wire is not easy to creep.
Insulation cover performance characteristics:
1. Power frequency withstand voltage: ≥18kv hold pressure for 1 minute without breakdown
2. Insulation resistance: >1.0×Ω
3. Ambient temperature: -30℃~90℃
4. Weather resistance: Good performance after 1008 hours of artificial weathering test.
Product installation and reliability
1. The degree of contamination of the contact surface when installing the parallel groove wire clip has a certain influence on the contact resistance. Before installing the wire clip, ensure that the wire groove is clean.
2. In the contact form of the parallel groove wire clip, the larger the contact area, the lower the contact resistance. When designing the wire clip, try to use surface contact and increase the contact area.
3. When the parallel groove clamp is installed, the greater the contact pressure, the smaller the contact resistance. Choose standard parts with well-processed and uniform coating, and apply conductive grease during installation, which can effectively improve the contact performance of the parallel groove clamp and reduce the contact resistance.
The reliability of the parallel groove clamp:
From the characteristics of metal materials, we know that under the condition of stress, the wire will inevitably produce a certain amount of creep, which is more serious in the parallel groove clamp with high local pressure, which makes the wire slightly thinner and the diameter decreases. Without a proper compensation function, the grip of the grooved wire clip on the wire will decrease, resulting in stress relaxation. When the material is determined, the creep of the wire is related to time, pressure, tension and ambient temperature. The greater the pressure or tension on the wire and the higher the ambient temperature, the more serious the creep of the wire, and the change curve is exponential and increases with time. growing and increasing.
In order to maintain the stability of the holding force of the parallel groove clamp on the wire, during construction and installation, there must be enough external force to generate a suitable pressure on the wire to prevent the parallel groove clamp and the wire from loosening or relative slippage; After the external force disappears, the parallel groove clamp should be able to provide a relatively constant pressure on the wire to compensate for the creep effect of the wire caused by changes in current, temperature, wind speed, corrosion, etc.
When the bolt-type parallel groove clamp is installed, the torque applied to the bolt or nut often varies from person to person, and generally no special measuring instrument is used to check the torque, resulting in different bolts of the same clamp or between clamps installed by different personnel. The resulting stress on the wire is inconsistent. If the pressure is too large, the wire will creep too much; if the pressure is too small, the clamp and the wire will lack sufficient pressure and gripping force in the early stage of operation. The quality of the spring washer also seriously affects the mechanical stability of the clip. If a poor spring washer is selected, the plastic deformation of the spring washer will be large after being subjected to external force, which will cause the installed wire clip to not obtain the proper pressure compensation when the wire creeps.
The H-type parallel groove wire clamp is installed with special hydraulic tools, and the pressure on the wire is relatively uniform and constant. The connection with the wire is a one-time hydraulic setting, so that the inner wall material of the wire clip is embedded in the outer layer of the wire. Because the wire clip and the outer strand of the wire are the same aluminum-based material, it can reduce stress relaxation and compensate for wire creep.
The best mechanical stability should belong to the wedge-type parallel groove clamp. Due to the use of the bow-shaped structure and the wedge block, when the wire creeps due to various reasons, the bow-shaped structure and the wedge block can compensate for the creep, and the initial pressure during installation is provided by the special bullet, which can be achieved by reasonable control of the dose. goal of controlling stress