toroidal core meaning in English

环形铁芯
环形铁心
环状铁心

Toroidal core transformer
环芯变压器
Edd - current power loss in partly stuffed toroidal cores with rectangular cross section
部分填充矩形截面环形磁芯的涡流损耗计算
Standard test method for alternating - current magnetic properties of toroidal core specimens using the voltmeter - ammeter - wattmeter method
使用伏特计-电流计-瓦特计方法测试环形铁芯试样交流磁性能的标准试验方法