Induction melting furnace induction wire coil copper tube cross-sectional dimension of the selection method
In order to improve the electrical efficiency and the convenience of winding, the copper tube of the induction melting furnace induction coil is made of a pure copper tube with a small resistivity, and is cooled by a cooling water in a pure copper tube during operation. When the coil works, the alternating current, due to the skin effect, the ring effect and the proximity effect between the blank, the current is concentrated on the inner side of the conductor, so that the cross-sectional area of the conductor is not fully utilized. When the thickness of the conductor is selected to be small, the current density on the conductor cross section increases, and the power loss of the inductor increases. When the thickness of the conductor is chosen to be large, it will result in an inefficient waste of copper. For a certain frequency of current, the conductor thickness is 1.57 times the penetration depth at this frequency , and the resistance value is the smallest, and the inductor can obtain the best electrical efficiency. In engineering, the actual application generally takes a conductor thickness greater than 1.2 times the current penetration depth.
The optimum wall thickness of the induction coil pure copper tube at different current frequencies and the actual use values can be referred to the following table:
Pure copper tube wall thickness ( mm ) | Current frequency ( Hz ) | ||||||
50 | 150 | 500 | 1000 | 2500 | 4000 | 8000 | |
Current penetration depth mm ( 50 °C) | 10.1 | 5.8 | 3.2 | 2.3 | 1.4 | 1.12 | 0.8 |
Optimum value mm | 15.9 | 9.1 | 5.0 | 3.6 | 2.2 | 1.76 | 1.3 |
Actual value mm | 12 | 7 | 4 | 3 | 2 | 1.34 | 1-1.5 |
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