電機啟動計算

電機啟動計算:????? 系統(tǒng)容量視為無窮大，變壓器為630KVA油浸變壓器，上級母線距車間母線采用2根185電纜連接（150米），電動機距車間母線50米。????????
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一、? 電動機不頻繁啟動????????
(1) 選用電機為75KW三相鼠籠異步電機????????
主要電氣參數(shù)????????
S"?SrT?xT?Skm? Qfh? Sfh?Xl?SqM?Sq
∽?0.63?0.045 ?14.00 ?0.302 ?0.504 ?0.039 ?0.645 ?0.549
IrM?UrM?kq?S?uqm?uqM???
0.140 ?0.380 ?7 ?70 ?0.963 ?0.82 ???
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(2) 選用電機為55KW三相鼠籠異步電機????????
主要電氣參數(shù)????????
S"?SrT?xT?Skm? Qfh? Sfh?Xl?SqM?Sq
∽?0.63?0.045 ?14.00 ?0.302 ?0.504 ?0.041 ?0.470 ?0.415
IrM?UrM?kq?S?uqm?uqM???
0.102 ?0.380 ?7 ?50 ?0.972 ?0.86 ???
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二、? 電動機頻繁啟動????????
(1) 選用電機為37KW三相鼠籠異步電機????????
主要電氣參數(shù)????????
S"?SrT?xT?Skm? Qfh? Sfh?Xl?SqM?Sq
∽?0.63?0.045 ?14.00 ?0.302 ?0.504 ?0.047 ?0.322 ?0.292
IrM?UrM?kq?S?uqm?uqM???
0.070 ?0.380 ?7 ?25 ?0.980 ?0.89 ???
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(2) 選用電機為30KW三相鼠籠異步電機????????
主要電氣參數(shù)????????
S"?SrT?xT?Skm? Qfh? Sfh?Xl?SqM?Sq
∽?0.63?0.045 ?14.00 ?0.302 ?0.504 ?0.054 ?0.322 ?0.288
IrM?UrM?kq?S?uqm?uqM???
0.070 ?0.380 ?7 ?16 ?0.980 ?0.87 ???
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一、? 電動機不頻繁啟動????????
?Skm=SrT/(xT+SrT/S")=14 (MVA)????????
(1) 選用電機為75KW三相鼠籠異步電機(SqM=0.645 MVA)。????????
?Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/70)*0.05=0.031+0.008=0.039????????
Sq=1/(1/SqM+Xl/U2m)=0.549????????
?Qfh=0.302????????
?uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.851=0.963????????
uqM =0.963*Sq/SqM=0.963*0.549/0.645=0.82????????
(2) 選用電機為55KW三相鼠籠異步電機(SqM=0.470MVA)。????????
?Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/50)*0.05=0.031+0.010=0.041????????
Sq=1/(1/SqM+Xl/U2m)=0.295????????
?Qfh=0.302????????
?uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.718=0.972????????
uqM =0.972*Sq/SqM=0.972*0.416/0.472=0.86????????
故電機功率為55KW三相鼠籠異步電機可直接啟動。????????
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二、? 電動機頻繁啟動????????
?Skm=SrT/(xT+SrT/S")=14 (MVA)????????
(1) 選用電機為30KW三相鼠籠異步電機(SqM=0.262 MVA)。????????
?Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/16)*0.05=0.031+0.023=0.054????????
Sq=1/(1/SqM+Xl/U2m)=0.288????????
?Qfh=0.302????????
?uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.541=0.984????????
uqM =0.983*Sq/SqM=0.983*0.2386/0.262=0.90????????
(2) 選用電機為30KW三相鼠籠異步電機(SqM=0.322 MVA)。????????
?Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/25)*0.05=0.031+0.016=0.047????????
?Qfh=0.302????????
Sq=1/(1/SqM+Xl/U2m)=0.292????????
?uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.597=0.980????????
uqM =0.980*Sq/SqM=0.980*0.307/0.322=0.89????????
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故電機功率為30KW三相鼠籠異步電機可直接啟動。????????