Recently, TBEA announced its 2005 Interim Report, which reported average performance in the first half of the year with no highlights. Similarly, Xu Ji's semi-annual report shows that although the main business income increased by 7.56% compared with the same period last year, the profit fell by 20.65%, of which the transformer business profit fell by a relatively large margin. Affected by factors such as rising raw material prices and increasing financing costs.
The transformer manufacturing industry itself is characterized by a relatively long delivery cycle, generally 3 to 6 months, and even longer than 1 year. TBEA, Tianwei Baobian and other large enterprises even signed some contracts in 2007, another domestic transformer manufacturer Xidian Group Xibian Company production tasks are also very saturated.
Special transformer for powering electric arc furnaces for steel smelting. Large capacity, complex structure and high technical requirements. Its secondary voltage is low, usually from tens of volts to hundreds of volts, and it is required to be adjustable within a wide range; the current of the secondary side often reaches thousands to tens of thousands of amperes. In addition, in steel smelting, the melting period requires large power, and the transformer is required to have 20% overload capacity within 2 hours. During the steelmaking process, because the collapse of the charge is likely to cause an electrode short circuit, the primary side of the arc furnace transformer should be connected to a current-limiting reactor or have a large impedance to limit the short-circuit current.
Electric furnace operation also requires that the power supply transformer can adjust the voltage. There are two ways to adjust the voltage of the electric furnace transformer .
On the primary winding of the transformer, the tap is connected to the tap changer. △ -Y conversion can also be used between the three phases on the primary side to achieve secondary side voltage adjustment. △ -Y switching is a very economical voltage regulation method. Without changing the number of turns on the primary side, the secondary side voltage can be reduced to the original 1 /. Because there are 9 taps for each phase winding, plus △ -Y conversion, a total of 2 × 9, that is, 18 levels of voltage can be obtained.
The main transformer 1 is a three-winding transformer, 1 is a high-voltage winding, and is connected to the power grid; 2 is a winding with a tap, and is connected in series with the original winding 4 of the series transformer Ⅱ through a tap switch; The winding 5 is connected in series to supply power to the electric furnace load. By changing the primary voltage of the series transformer Ⅱ through the tap changer, the output voltage of the 3 and 5 windings can be changed. The 3 and 5 windings connected to the load usually have only 1 or 2 turns, and usually a figure 8 coil is made of copper or aluminum plate.
However, the prices of the products in the contract were calculated based on the prices of the raw materials at that time. Most manufacturers did not expect that the prices of raw materials would rise so rapidly. Therefore, its performance is not fully reflected. Recently, Wuhan Iron and Steel Co., Ltd. adjusted the sales prices of some products in September this year. Against the background of various steel product price reductions, the prices of oriented silicon steel sheets have instead increased by 2,000 yuan / ton, and further price increases may not be ruled out.