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基于80c51單片機的漏電保護裝置設(shè)計-在線瀏覽

2025-03-05 10:18本頁面
  

【正文】 、壓差小、靜態(tài)電流小、外接元件小的優(yōu)勢。綜合比較之后,選擇方案四。電流漏電檢測電路實現(xiàn)對三相交流電電壓、電流和漏電的檢測,以實現(xiàn)對過壓、欠壓、過流和漏電的保護。電流檢測由三相交流互感器、整流濾波電路和分壓電路組成。此電路質(zhì)量可靠,抗干擾性強。讓ADC0804能測得康銅絲兩端的電壓差。價格便宜、對電路影響可忽略不計、其阻值低、精度高、溫度系數(shù)低、具有無電感、高過載能力。經(jīng)過測試,在1Ω的康錳銅電阻絲上通過約2A電流,由于產(chǎn)生的熱量引起的升溫,對電流的穩(wěn)定起了很重要的作用。 關(guān)斷保護電路的設(shè)計方案一:漏電保護電路主要包括:檢測元件(零序電流互感器)、中間環(huán)節(jié)(放大器、比較器、脫扣器)、執(zhí)行元件(主開關(guān))等幾個部分。當(dāng)發(fā)生漏電或者有人觸電時,通過零序電流互感器一次測各相電流相量和不再等于零,產(chǎn)生了漏電電流。方案二:通過單片機I/O口控制,驅(qū)動電磁繼電器。當(dāng)輸入低電平時,晶體管截止,繼電器線圈斷電,觸點斷開。方案三:IGBT(絕緣柵雙極型晶體管)兼有場效應(yīng)晶體管輸入阻抗高、驅(qū)動功率小和雙極型晶體管電壓、電流容量大及管壓降低的特點。為了實現(xiàn)IGBT的短路保護,則必須進行過流檢測??紤]到可行性,綜合比較之后:選擇方案二。公式:。電阻增大則電路效率下降,所以康銅絲對電路的影響可以完全忽略不計。因取樣電壓很小很小,故使用INA128對它進行放大1000倍,使它有一個穩(wěn)定的電壓值。 圖6 采樣電路的設(shè)計 漏電檢測電路設(shè)計圖7 30mA漏電檢測電路 關(guān)斷保護電路的設(shè)計51單片機控制繼電器驅(qū)動原理:當(dāng)51單片機引腳輸出低電平時,三極管2N3906飽和導(dǎo)通,+5V電源加到繼電器線圈兩端,繼電器吸合,同時狀態(tài)指示的發(fā)光二極管也點亮,繼電器的常開觸點閉合,相當(dāng)于開關(guān)閉合。注:在三極管截止的瞬間,由于線圈中的電流不能突變?yōu)榱悖^電器線圈兩端會產(chǎn)生一個較高電壓的感應(yīng)電動勢,線圈產(chǎn)生的感應(yīng)電動勢則可以通過二極管IN4148釋放,從而保護了三極管免被擊穿,也消除了感應(yīng)電動勢對其他電路的干擾,這就是二極管D1的保護作用。采用低噪聲、高共模抑制、高輸入阻抗、低功耗的高性能儀表放大器INA128。圖11 報警電路三、程序設(shè)計主程序設(shè)計:圖12 主程序流程圖四、測試方案與測試結(jié)果UT39A數(shù)字萬用表、KXN30400高精密數(shù)字萬用表、UT805微機電源。:表3 負載調(diào)整率測試輸出電流(A)111輸出電壓(V)5負載調(diào)整率: ()/5*100%=%。 系統(tǒng)對題目的完成情況:表4 系統(tǒng)對題目的完成情況對照表基本部分要求實現(xiàn)輸出電壓5V輸出電壓5V最大輸出電流1A符合要求電壓調(diào)整率Su≤1%%負載調(diào)整率SL≤1%%輸入變化時輸出為5177。顯示輸出功率有顯示過流保護的動作電流30mA發(fā)揮部分漏電保護裝置沒有動作時,輸出電壓≥漏電保護裝置電流誤差絕對值≤5%實際誤差≤1%要求接入功耗低實際功耗低 結(jié)果分析: 各項結(jié)果都符合系統(tǒng)指標(biāo),產(chǎn)生誤差的原因包括:電阻精度不夠等。本次競賽極大的鍛煉了我們各方面的能力,雖然我們遇到了很多困難和障礙,但總體上成功與挫折交替,困難與希望并存,我們將繼續(xù)努力爭取更大的進步。 you don39。 your employer dismisses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, seetagainst the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal.Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept it.If you are worried about how the time limits apply to you, take advice from one of the organisations listed underFurther help.If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your pensation if you win the case. This is known as at charge you more than 35% of your pensation a damagesbased agreement, you should make sure you39。To find your nearest CAB, including those that give advice by , click onEmployment tribunals.The (lack of) air up there Watch mCayman Islandsbased Webb, the head of Fifa39。s 150th anniversary celebrations and will attend City39。s about how he felt and I would like to speak to him first to find out what his experience was.Uefa
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