three-to-single-phase welding transformer

例句：

1. 1. Thethree-phase welding transformer is essential for the power grid system.
   三相焊接变压器对于电网系统至关重要。
2. 2.The three-phase transformer was installed in the substation to improve its efficiency.
   在变电站安装的三相变压器是为了提高其效率。
3. 3. The three-phase welding transformer is used to convert alternating current into direct current.
   三相焊接变压器用于将交流电转换为直流电。