現在無刷摩打的磁芯大部分都是用上 Neodymium magnets (網上中文名叫釹磁, 唔敢肯定), 銀色很強磁力那些. 當溫度超過 80C, 磁力便會下降, 下降多少, 由質料決定. 我在網上找一些資料給大家參考.
Neodymium magnets are most powerful of any kind of magnetic materials
Br of Neodymium magnets are much more than 11,000 Gauss. Therefore, Neodymium magnets have strong holding strength on metal surface and could be used as component for holding, separating, etc.
Neodymium magnets must be carefully handled to avoid personal injury and material damage due to its extremely magnetic strength and brittle property.
Neodymium magnets are sensitive to temperature change and even lose magnet properties at high temperature
Neodymium magnets lose -0.09 ~ -0.13% of Br/°C and can work stably under 80°C for low Hci Neodymium magnets and 150°C for high Hci Neodymium magnets.
Neodymium magnets are corrupted in humid environment
Surface protection is strongly recommended, such as plating, varnishing and encapsulating.
Neodymium magnets are hard and brittle
Neodymium magnets can be abrasively machined with coolant served to absorb heating and dust. Without coolant, rare earth magnets could crack and chip by the heat produced during high speed cutting or grinding, and the sparks contain the easily oxidized grinding dust that could cause fire!
Tolerance of Neodymium magnets
Unless otherwise specified, tolerance on dimension of magnetization is ±.005”. Other dimensions are ±1.5% or ±.010”, whichever is greater.
所以我們有需要考慮摩打溫度, 避免過高.
至於摩打的 SPEC. 小弟也不太清楚, 只知道 MMM 的摩打在同一工作轉數下溫度比較低.
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樓主: sakura119
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