20AD5P0A3AYNANC0 20AD5P0A3AYNANC0
優(yōu)勢品牌:Allen-Bradley Siemens ABB
庫存現(xiàn)貨 *優(yōu)惠
陜西欣鴻然自動化設(shè)備有限公司
:寧超
:
:1293858601
:1293858601
傳真:
地址:西安市灞橋區(qū)浐河東路水岸東方1單元14棟602室。
基本組成
變頻器通常分為4部分:整流單元、高容量電容、逆變器和控制器。
整流單元:將工作頻率固定的交流電轉(zhuǎn)換為直流電。
高容量電容:存儲轉(zhuǎn)換后的電能。
逆變器:由大功率開關(guān)晶體管陣列組成電子開關(guān),將直流電轉(zhuǎn)化成不同頻率、寬度、幅度的方波。
控制器:按設(shè)定的程序工作,控制輸出方波的幅度與脈寬,使疊加為近似正弦波的交流電,驅(qū)動交流電動機。
(1)運算電路:將外部的速度、轉(zhuǎn)矩等指令同檢測電路的電流、電壓信號進行比較運算,決定逆變器的輸出電壓、頻率。
(2)電壓、電流檢測電路:與主回路電位隔離檢測電壓、電流等。
(3)驅(qū)動電路:驅(qū)動主電路器件的電路。它與控制電路隔離使主電路器件導通、關(guān)斷。
(4)速度檢測電路:以裝在異步電動機軸機上的速度檢測器(tg、plg等)的信號為速度信號,送入運算回路,根據(jù)指令和運算可使電動機按指令速度運轉(zhuǎn)。
(5)保護電路:檢測主電路的電壓、電流等,當發(fā)生過載或過電壓等異常時,為了防止逆變器和異步電動機損壞
直流電動拖動和交流電動機拖動先后生于19世紀,距今已有100多年的歷史,并已成為動力機械的主要驅(qū)動裝置。由于當時的技術(shù)問題,在很長的一個時間內(nèi),需要進行調(diào)速控制的拖動系統(tǒng)中則基本上采用的是直流電動機。
直流電動機存在以下缺點是由于結(jié)構(gòu)上的原因:
1、由于直流電動機存在換向火花,難以應用于存在易燃易爆氣體的惡劣環(huán)境;
2、需要定期更換電刷和換向器,維護保養(yǎng)困難,壽命較短;
3、結(jié)構(gòu)復雜,難以制造大容量、高轉(zhuǎn)速和高電壓的直流電動機。
(1)信號線與動力線要垂直交叉或分槽布線。
(2)不要采用不同金屬的導線相互連接。
(3)屏蔽管(層)應可靠接地,并保證整個長度上連續(xù)可靠接地。
(4)信號電路中要使用雙絞線屏蔽電纜。
(5)屏蔽層接地點盡量遠離變頻器,并與變頻器接地點分開。
(6)磁環(huán)可以在變頻器輸入電源線和輸出線上使用,具體方法為:輸入線一起朝同一方向繞4圈,而輸出線朝同一方向繞3圈即可。繞線時需注意,盡量將磁環(huán)靠近變頻器。
(7)一般對被干擾設(shè)備儀器,均可采取屏蔽及其它抗干擾措施。
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The gentleman is not close to the evil.Emperor lost ground, name;Out the surname, name.
A minister of the: don't fight.Three to fight and don't listen to, it escaped.
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