Introduction of main main bus grooves in the market
1, air type (insulation) composite insulating air type busbar is divided into ordinary and high strength, the difference is not great, after 20 years of development, with the process of change and new materials appear continuously, the old air and high strength has gradually withdrawn from the market, replacing them is "imitation of German" the product, the product will be made one set of their underlying potential, their respective advantages, reasonable and effective to avoid the disadvantages.
2, in order to solve the problem of large current transportation in coastal areas or outdoor areas, the casting busbar has a waterproof casting busbar in the market in 2000. This bus bar belongs to a special branch product. It is made of copper or aluminum (copper and aluminum) as conductor, insulation resin as shell, and molded in a certain shape mold. The joint part is cast after field connection, so the whole bus system is completely waterproof. Advantages: dustproof and waterproof, it can work under water for a long time. Disadvantages: hermetic and poor radiation effect, the same specifications of busbar section need to increase, not with plug-in unit (box).
3, the intensive bus has talked about the structure and advantages and disadvantages of the dense bus bar. The advantage of the dense bus is fast heat dissipation. Therefore, the mainstream intensive busbars are made of aluminum alloy material with better thermal conductivity. When it comes to heat must be aware of an electrical conductor (common sense, the same way with the same material, the same section of insulation, the same) at ambient temperature and conductivity are not the same, see the table below: correction coefficient table type K temperature conductor ampacity temperature (c) -5 05101520253035 404550 902.14 1.95 1.14 1.11 bare conductor 1.07 1.04 1 0.96 0.92 0.88 0.83 0.7770 1.29 1.24 1.20 1.15 1.11 1.05 1 0.94 0.88 0.81 0.74 0.67 801.24 1.20 1.17 1.13 1.09 1.04 cable 1 0.95 0.90 0.85 0.8070 1.29 1.24 1.20 1.15 1.11 1.05 1 0.94 0.88 0.81 0.7465 1.32 1.27 1.22 1.17 1.12 1.06 1 0.94 0.87 0.79 0.7160 1.36 1.31 1.25 1.20 1.13 1.07 1 0.93 0.85 0.76 0.6655 1.41 1.35 1.29 1.23 1.15 1.08 1 0.91 0.82 0.71 0.5850 1.48 1.41 1.34 1.26 1.18 1.09 1. 0.89 0.78 0.63 0.45
Note: (1) the K column in this table shows the permissible working temperature of the conductor, and the unit is "degree".
(2) this table is mainly used for bare conductors and cables.
(3) the standard ambient temperature of the rated flow rate is 25.
(4) the geographical line can be corrected by the reference cable allowing the working temperature to be 65 degrees centigrade. Therefore, conductor temperature rise and cut-off flow is a vicious spiral, when the temperature rise, decline and closure of conductor capacity, current carrying capacity decline will lead to increased temperature rise, from this point we can understand the function, good heat dissipation conditions of busbar plays a very important role.
Several important ways to achieve good heat dissipation are:
The overall structure of a, intensive is close to the bus conductor, and the shell is also close to the assembly, by air cooling principle type "convection" into "intensive heat conduction";
B, the aluminum alloy material with better thermal conductivity is used as the shell, so that the heat dissipation speed is quickened.
C, conductor insulation materials select new materials (such as fixed polyester film, etc.), instead of PVC casing. Because heat shrinkable sleeves are generally insulating materials with low thermal conductivity, heat shrinkable sleeves are rarely used in current dense bushings.
D, the middle of the conductor (mainly in the middle of B, C) with aluminum plate heat sink, heat sink and shell connection, increase the surface of heat dissipation, improve the effect of heat dissipation. This way can reduce the temperature rise to a certain extent, but the cost gap between material and labor cost and copper cost is not clear. The importance of bus cooling is mentioned above. In fact, in the final analysis, the purpose of improving the cooling effect is to reduce the cross section of conductor under the same current to save cost, which is also an important reason for the popularity of aluminum alloy shell and busbar trough in the market.