[心得] 汽車接地迴路阻抗不專業測試
汽車電系中,發電機及各用電裝置,都是靠車身金屬部分接通電池負極,之前坊間的強化
接地,就是從主要組件上,額外拉接地線與電池負極連接,可以降低車身金屬部分阻抗所
產生的傳輸損失,到底車身金屬部分的阻抗有多大呢?以下是在下的不專業測試
被測對象:Honda CITY 一年車
電池正負極間的內阻,為9.43mΩ
http://i.imgur.com/p46ROuR.jpg
電池負極與車身金屬部分的連接線為3.35mΩ
http://i.imgur.com/Mv47Gwx.jpg
引擎變速箱接地線與電池負極間阻抗為6.9mΩ
http://i.imgur.com/NvIZyrG.jpg
引擎左側引擎腳接地線與車身連接線為2.14mΩ
http://i.imgur.com/ysJH0Nl.jpg
發電機外殼螺絲與引擎腳阻抗為2.06mΩ
http://i.imgur.com/DI26dxp.jpg
啟動馬達外殼螺絲與電池負極間阻抗為5.09mΩ
http://i.imgur.com/5e4V3H3.jpg
因為手上測試儀器的線不夠長,沒辦法直接從電池負極測量到發電機、左側引擎腳部分的
接地阻抗,從電池負極連接線3.35 mΩ來看,發電機外殼螺絲到電池負極會有2.06+3.35
mΩ的阻抗,左側引擎腳到電池負極會有2.14+3.35 mΩ的阻抗
結論:
阻抗對電流傳輸的影響,流過的電流X阻抗,就會產生壓降,電流越大,壓降越大,啟動
馬達在發動引擎瞬間會消耗最大的電流,引擎發動後車上發電機負責提供整車所需的電力
,這兩個都是會有大電流流動的元件,也最容易被接地電阻影響,所以對接地系統進行強
化,發電機與起動馬達可以優先列入強化考慮
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※ 文章網址: https://www.ptt.cc/bbs/car/M.1491832421.A.737.html
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04/10 21:55, , 1F
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04/10 21:56, , 2F
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※ 編輯: wolflsi (1.175.77.27), 04/10/2017 22:00:03
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04/10 22:02, , 5F
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因為正電線路已經經過保險絲了
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04/10 22:03, , 6F
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當車子使用時間增長,線路/接合面氧化後阻抗會增加
※ 編輯: wolflsi (1.175.77.27), 04/10/2017 22:04:51
噓
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是的
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因為測棒都是測在負電線路,兩端當然沒有電壓(或是測試器的電壓檔量不出來),
只用到此測試器的內阻測試功能
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這款測試器兩組測棒短路讀數為0.5mΩ
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04/11 00:00, , 33F
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※ 編輯: wolflsi (1.175.77.27), 04/11/2017 00:09:41
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測試這台車原廠就在引擎與變速箱各接一條地線到車身
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這款使用四線式探棒,也有測試多次看數值是否差異過大
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對岸便宜貨YR1030
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數改也算蠻久了(擦汗)
※ 編輯: wolflsi (115.82.148.3), 04/11/2017 12:27:20
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