How to choose welding cable?
Selection of welding cables
Welding cable refers to connecting a primary side coil of the machine, a bracket, and a grounding clip to form a welding circuit cable.
In order to make the welding operation convenient and flexible, soft welding cables should be used, especially near the welding area of 2-3m. The wires should be flexible cables as far as possible. If the welding position is fixed, you can also choose hard wiring for grounding, but must not use iron or iron frame to overlap, otherwise, not only a lot of electric energy is wasted, but also the welding performance may be affected by the excessive grounding voltage drop. Among the cable products in our country, there are special types of YHH welding rubber flexible cables and YHHR type special flexible welding cables
The length of the welding cable is mainly determined according to the production needs. Large-scale welding personnel or in order to expand the working range of the welder can appropriately extend the welding cable, but it should be noted that as the welding cable grows, its resistance value increases, and the power loss also increases. For example, the cross-sectional area of the 60mm2 cable , if the load current is 300A. When the total length is 40m, the power loss is 1.15kW. When the total cable length is increased to 8Om, the power loss increases to 2.3kW. Therefore, from an energy saving point of view, the shorter the welding cable, the better.
In addition, the welding current through the welding cable also produces a large voltage drop, which causes the welding current to drop. Therefore, the no-load voltage should be limited to 5% (i.e. no more than 4V) using the voltage drop on the welding cable. For on-site installation and welding, the welding positions are divided into far, near, high and low, and the method of lengthening the welding cable in sections can be used. About 10m between the end of the connecting cable and the installation can be fixed, and the welding can be lengthened or shortened as needed.
The selection of the cross section of the welding cable should consider two factors: temperature rise (current) and voltage drop. Welding cables with a length of 2Om are negligible, the effect of the voltage drop is negligible, and only the size of the weld in the load is selected. On YHH cables, when the length is more than 20m, the current density is generally 4 - 10 Am. When thicker cables are used, lower current densities should be used. When the length of the welding cable exceeds 50m, in addition to the temperature rise, the voltage drop should not exceed 4V. For example, for the following welding cable with a length of 20mm, when the welding current is 300A, the load duration is 60%, then 300Ax60%=300Ax0.78=234A current selection welding cable. If the current density is mm2/7A, the cable cross section should be 7A/234A/mm2=33.4mm2. YHH-35 rubber sheathed flexible cable can be used.