https://www.youtube.com/watch?v=CWulQ1ZSE3c
https://www.youtube.com/watch?v=59HBoIXzX_c&ab_channel=TheEngineeringMindset
淺談節能水車：會變頻的不只有空調 養殖業也用得到！ - 農傳媒
3 Consequences Of Improper Generator Synchronisation