This product is a high-tech product oriented towards the 21st century. It has novel design, advanced performance, safety and reliability, high technical indicators, beautiful appearance and small volume. It is the first choice for three-phase load imbalance treatment. The manual phase change switch for three-phase unbalance treatment can effectively reduce the terminal low voltage, voltage drift, etc. caused by the increase of transformer loss, line loss, transformer output reduction and other reasons caused by three-phase load imbalance, as well as many safety hazards caused by three-phase imbalance. Reduce the frequency of overvoltage/undervoltage caused by three-phase load imbalance.