https://blog.gongquiz.com/2023/01/08/%ec%a0%95%ea%b2%a9%ec%a0%84%ec%95%95-250v-%ec%a0%95%ea%b2%a9%ec%b6%9c%eb%a0%a5-50kw%ec%9d%98-%ec%99%b8%eb%b6%84%ea%b6%8c-%eb%b3%b5%ea%b6%8c%eb%b0%9c%ec%a0%84%ea%b8%b0%ea%b0%80-%ec%9e%88%eb%8b%a4/