選粉機(jī)上的應(yīng)用:傳統(tǒng)的選粉機(jī)是電磁調(diào)速異步電動(dòng)機(jī)(滑差電機(jī))拖動(dòng),其優(yōu)點(diǎn)是調(diào)速系統(tǒng)簡(jiǎn)單、價(jià)格低廉、有一定的調(diào)速范圍,缺點(diǎn)也較多,電機(jī)本體噪音高、振動(dòng)大、能耗高、功率損耗大、軸承故障率特高,滑差控制儀安裝于粉塵飛揚(yáng)的電機(jī)旁邊,多次出現(xiàn)帶負(fù)荷起動(dòng),不能調(diào)速和突然失速等故障,現(xiàn)場(chǎng)維護(hù)量大,影響整個(gè)系統(tǒng)的安全運(yùn)行。
2.2變頻器容量的合理選配
變頻器容量選定過程,實(shí)際上是變頻器與電機(jī)的最佳匹配過程,最常見、也較安全的辦法,是按變頻器生產(chǎn)廠家要求,即變頻器的功率應(yīng)大于或等于電動(dòng)機(jī)額定功率的1.1倍。
但水泥廠設(shè)備選型時(shí),所選能力都比實(shí)際需要作了放大,拖動(dòng)電機(jī)又在所選設(shè)備基礎(chǔ)上留有一定的裕量,這樣在實(shí)際運(yùn)行中,運(yùn)行負(fù)荷常常只有額定裝機(jī)功率的60~70%。所以合理的選擇方法應(yīng)以設(shè)備的實(shí)際運(yùn)行情況為基礎(chǔ)進(jìn)行計(jì)算和分析,決定變頻器的容量。這不僅能節(jié)省投資,而且本身也是一種節(jié)能降耗的措施。根據(jù)資料和經(jīng)驗(yàn),可按下列方法選配:
(1)電機(jī)實(shí)際功率確定法。首先測(cè)定電機(jī)的實(shí)際功率,以此來選用變頻器的容量。
(2)公式法。安全系數(shù)取1.05,則變頻器的容量為:
Pb=1.05Pm/hm×cosy(kW)
式中,Pm為電機(jī)負(fù)載,hm為電機(jī)效率,cosy電機(jī)功率因數(shù)。
(3)按電機(jī)的實(shí)際功率選擇變頻器,一定要注意:①電機(jī)加載后總的負(fù)荷電流不得超過變頻器的額定電流;②負(fù)載峰值電流不得超過變頻器的過載量。運(yùn)行經(jīng)驗(yàn)表明,變頻器的容量最小不得小于電機(jī)容量的65%。
在下列情況下使用普通變頻器還須增大變頻器的容量,一般向上放大一檔:①起動(dòng)時(shí)機(jī)械慣量較大的負(fù)載;②要求電動(dòng)機(jī)頻繁進(jìn)行加、減速;③在希望的加減速時(shí)間內(nèi),電機(jī)最大電流大于變頻器的過載容量(當(dāng)1min內(nèi)達(dá)1.5倍額定電流時(shí))。
2.3水泥廠變頻器使用時(shí)應(yīng)注意以下問題
(1)使用環(huán)境。變頻器的額定容量是針對(duì)一定的使用環(huán)境而標(biāo)出的,變頻器工作溫度一般要求為0℃~55℃,最好控制在40℃以下,相對(duì)濕度應(yīng)控制在20%~90%。變頻器對(duì)環(huán)境溫度要求較高,同時(shí)它又是發(fā)熱量較大的設(shè)備,水泥廠在使用大功率變頻器時(shí),在考慮降溫時(shí),一定要考慮變頻器的發(fā)熱,一般按變頻器容量的3~4%的功率核算變頻器的發(fā)熱量。critical process point is separation and inactivation. A large amount of ethanol is used in the separation process, which has the risk of explosion. Therefore, corresponding countermeasures should be taken to ensure the safety of production. Rongsheng pharmaceutical needs to upgrade its production facilities for blood products due to various considerations. First, modernize production. The equipment of old factories has long been out of date, and it is more and more difficult to meet the requirements of modern production standards and GMP. Second, improve production capacity. In the Chinese market, the demand for blood products is growing rapidly. Finally, we take "pursuing the leading of product technology and quality" as our development strategy, rather than becoming the so-called largest blood products company. In 2004, the basic design of the project was completed, and the engineering company selected by Rongsheng pharmaceutical recommended Siemens