一、通信電源為什么是-48V
1、-48V的電(dian)(dian)源(yuan)電(dian)(dian)壓會比較(jiao)安全一點:例(li)如人身體是(shi)50K歐姆電(dian)(dian)阻,電(dian)(dian)壓-48V,48/50000=0.00096A=0.96mA,人體流(liu)過9mA就有生命危險了。
2、歷史的(de)沿襲:多(duo)年前,使(shi)用(yong)(yong)電(dian)子管和(he)PNP型鍺管的(de)時候(hou),電(dian)路正極接(jie)地來得直(zhi)觀簡單方便。負電(dian)源(yuan)的(de)抗干擾性(xing)要(yao)好一些,不過這是很久以(yi)前的(de)原因,現在的(de)數字(zi)化技術(shu)對這要(yao)求已(yi)不高,所以(yi)現在設備也(ye)有用(yong)(yong)正電(dian)源(yuan),但考慮習慣通用(yong)(yong)性(xing)大多(duo)也(ye)還是-48V。
3、電(dian)源系統正(zheng)極接地可以減少蓄(xu)電(dian)池正(zheng)極的(de)腐蝕現(xian)象(xiang)。
4、降低(di)系(xi)統雜音,減少干擾(rao)。
5、早期通信可用大(da)地(di)作回路,節(jie)約線材。
6、為保護線(xian)纜,使(shi)其不會由于電池反(fan)應而被腐蝕,線(xian)纜必須為負極(ji)。
7、電壓(ya)比-24V高,有利于電量傳輸,減(jian)少損耗(hao)。
二、通信電源系統有哪幾部分組成?
1、交流(liu)配(pei)電(dian)(dian)(dian)單元:交流(liu)配(pei)電(dian)(dian)(dian)單元將市電(dian)(dian)(dian)接入,經過(guo)切換(huan)送入系(xi)(xi)統,交流(liu)電(dian)(dian)(dian)經分(fen)配(pei)單元分(fen)配(pei)后,一(yi)部(bu)(bu)分(fen)提供給開(kai)關整(zheng)流(liu)器,一(yi)部(bu)(bu)分(fen)作為備(bei)用輸出,供用戶使用。 系(xi)(xi)統可以由(you)兩(liang)路市電(dian)(dian)(dian)(或一(yi)路市電(dian)(dian)(dian)一(yi)路油機(ji))供電(dian)(dian)(dian),兩(liang)路市電(dian)(dian)(dian)主備(bei)工(gong)作方式,平(ping)時(shi)由(you)市電(dian)(dian)(dian)1供電(dian)(dian)(dian),當市電(dian)(dian)(dian)1發生(sheng)故(gu)障時(shi),切換(huan)到市電(dian)(dian)(dian)2(或者油機(ji)),在切換(huan)過(guo)程中(zhong),通(tong)信設備(bei)的供電(dian)(dian)(dian)由(you)蓄電(dian)(dian)(dian)池來供給。
2、整流(liu)(liu)(liu)(liu)部分(fen):整流(liu)(liu)(liu)(liu)部分(fen)的功能是將由(you)交流(liu)(liu)(liu)(liu)配電(dian)單(dan)元(yuan)提供的交流(liu)(liu)(liu)(liu)電(dian)變換成48V或(huo)者24V直流(liu)(liu)(liu)(liu)電(dian)輸出到直流(liu)(liu)(liu)(liu)配電(dian)單(dan)元(yuan)。整流(liu)(liu)(liu)(liu)部分(fen)包括整流(liu)(liu)(liu)(liu)模(mo)塊(kuai)和結構部分(fen)(機(ji)架)。
3、直流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)元(yuan)(yuan):直流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)元(yuan)(yuan)完(wan)成直流(liu)(liu)(liu)的(de)分配(pei)(pei)(pei)和備用電(dian)(dian)池(chi)組的(de)接(jie)入。開(kai)關(guan)整流(liu)(liu)(liu)器的(de)輸(shu)(shu)出(chu)(chu)經匯(hui)流(liu)(liu)(liu)母排接(jie)入直流(liu)(liu)(liu)配(pei)(pei)(pei)電(dian)(dian)單(dan)元(yuan)(yuan),配(pei)(pei)(pei)電(dian)(dian)單(dan)元(yuan)(yuan)為負載分配(pei)(pei)(pei)不同(tong)容量的(de)輸(shu)(shu)出(chu)(chu),可滿(man)足不同(tong)的(de)需要,后備電(dian)(dian)池(chi)組的(de)輸(shu)(shu)入與開(kai)關(guan)整流(liu)(liu)(liu)器輸(shu)(shu)出(chu)(chu)匯(hui)流(liu)(liu)(liu)母排并聯,以保證開(kai)關(guan)整流(liu)(liu)(liu)器無輸(shu)(shu)出(chu)(chu)時,后備電(dian)(dian)池(chi)組能向負載供電(dian)(dian)。
4、蓄電池組(zu):通(tong)信電(dian)源系統(tong)中采用(yong)整流(liu)器和(he)蓄(xu)電(dian)池(chi)(chi)組(zu)并(bing)聯(lian)冗余(yu)供電(dian)方式。蓄(xu)電(dian)池(chi)(chi)組(zu)既為備(bei)用(yong)電(dian)源,又可以吸收(shou)高頻紋(wen)波(bo)電(dian)流(liu)。目(mu)前(qian)常用(yong)的蓄(xu)電(dian)池(chi)(chi)為閥控式密(mi)封鉛酸蓄(xu)電(dian)池(chi)(chi),即(ji)VRLA,因(yin)為較之傳統(tong)的開(kai)口型電(dian)池(chi)(chi)密(mi)封性好、自放(fang)電(dian)小(xiao)、壽命(ming)長,又被稱為“免維護(hu)蓄(xu)電(dian)池(chi)(chi)”。
5、監(jian)(jian)(jian)(jian)控(kong)(kong)系(xi)統(tong):監(jian)(jian)(jian)(jian)控(kong)(kong)系(xi)統(tong)以多(duo)(duo)級(ji)自(zi)下而上(shang)逐級(ji)匯(hui)接的方式構成。每個監(jian)(jian)(jian)(jian)控(kong)(kong)級(ji)一般按輻射(she)方式與若干下級(ji)監(jian)(jian)(jian)(jian)控(kong)(kong)級(ji)連接成一點(dian)對多(duo)(duo)點(dian)的監(jian)(jian)(jian)(jian)控(kong)(kong)系(xi)統(tong),最低一級(ji)為設備(bei)監(jian)(jian)(jian)(jian)控(kong)(kong)單元(監(jian)(jian)(jian)(jian)控(kong)(kong)模塊)與其(qi)監(jian)(jian)(jian)(jian)控(kong)(kong)的若干設備(bei)的連接。