电机启动电流计算公式

SSrTxTSkmQfhSfhXlSqMSq∽10.05518.180.4800.8000.0340.6450.561IrMUrMkqSuqmuqM0.1400.38071500.9710.844SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0130.4700.450IrMUrMkqSuqmuqM0.1020.38071500.9690.93主要电气参数(1)选用电机为75KW三相鼠笼异步电机(2)选用电机为55KW三相鼠笼异步电机主要电气参数1、电动机频繁启动电动机启动计算系统容量视为无穷大，变压器为630KVA油浸变压器，上级母线距车间母线采用2根185电缆连接（150米），电动机距车间母线50米。一、计算数据系统示意图1-1SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0131.1291.022IrMUrMkqSuqmuqM0.2450.38071500.9330.84SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0140.9400.862IrMUrMkqSuqmuqM0.2040.38071200.9430.861、电动机不频繁启动Skm=SrT/(xT+SrT/S)=14(MVA)(1)选用电机为75KW三相鼠笼异步电机(SqM=0.645MVA)。Xl=(0.07+6.3/185)*0.5*0.15+(0.07+6.3/70)*0.05=0.031+0.008=0.039Sq=1/(1/SqM+Xl/U2m)=0.549Qfh=0.3020uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.851=0.963uqM=0.963*Sq/SqM=0.963*0.549/0.645=0.82(2)选用电机为55KW三相鼠笼异步电机(SqM=0.470MVA)。Xl=(0.07+6.3/185)*0.5*0.15+(0.07+6.3/50)*0.05=0.031+0.010=0.041二、计算过程uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.718=0.972主要电气参数(2)选用电机为110KW三相鼠笼异步电机2、电动机不频繁启动(1)选用电机为132KW三相鼠笼异步电机主要电气参数uqM=0.972*Sq/SqM=0.972*0.416/0.472=0.86Sq=1/(1/SqM+Xl/U2m)=0.295Qfh=0.302工厂配电设计手册150页表6-16，钢铁手册下册193页表23-42、电动机频繁启动Skm=SrT/(xT+SrT/S)=14(MVA)故电机功率为30KW三相鼠笼异步电机可直接启动。(2)选用电机为30KW三相鼠笼异步电机(SqM=0.263MVA)。Xl=(0.07+6.3/185)*0.5*0.15+(0.07+6.3/16)*0.05=0.031+0.023=0.054Qfh=0.302uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.541=0.984uqM=0.984*Sq/SqM=0.984*0.239/0.263=0.90Sq=1/(1/SqM+Xl/U2m)=0.292Qfh=0.302Sq=1/(1/SqM+Xl/U2m)=0.239Xl=(0.07+6.3/185)*0.5*0.15+(0.07+6.3/25)*0.05=0.031+0.016=0.047故电机功率为55KW三相鼠笼异步电机可直接启动。(1)选用电机为37KW三相鼠笼异步电机(SqM=0.322MVA)。uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.594=0.980uqM=0.98*Sq/SqM=0.98*0.292/0.322=0.89SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0390.6450.549IrMUrMkqSuqmuqM0.1400.3807700.9630.82SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0410.4700.415IrMUrMkqSuqmuqM0.1020.3807500.9720.86(1)选用电机为75KW三相鼠笼异步电机一、电动机不频繁启动电动机启动计算系统容量视为无穷大，变压器为630KVA油浸变压器，上级母线距车间母线采用2根185电缆连接（150米），电动机距车间母线50米。(2)选用电机为55KW三相鼠笼异步电机主要电气参数主要电气参数二、电动机频繁启动(1)选用电机为37KW三相鼠笼异步电机主要电气参数SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0470.3220.292IrMUrMkqSuqmuqM0.0700.3807250.9800.89SSrTxTSkmQfhSfhXlSqMSq∽0.630.04514.000.3020.5040.0540.3220.288IrMUrMkqSuqmuqM0.0700.3807160.9800.87一、电动机不频繁启动Skm=SrT/(xT+SrT/S)=14(MVA)(1)选用电机为75KW三相鼠笼异步电机(SqM=0.645MVA)。Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/70)*0.05=0.031+0.008=0.039Sq=1/(1/SqM+Xl/U2m)=0.549Qfh=0.302uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.851=0.963uqM=0.963*Sq/SqM=0.963*0.549/0.645=0.82(2)选用电机为55KW三相鼠笼异步电机(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(2)选用电机为30KW三相鼠笼异步电机主要电气参数Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/16)*0.05=0.031+0.023=0.054uqM=0.972*Sq/SqM=0.972*0.416/0.472=0.86故电机功率为55KW三相鼠笼异步电机可直接启动。(1)选用电机为30KW三相鼠笼异步电机(SqM=0.262MVA)。Sq=1/(1/SqM+Xl/U2m)=0.295Qfh=0.302Sq=1/(1/SqM+Xl/U2m)=0.288Qfh=0.302uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.541=0.984uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.718=0.972二、电动机频繁启动Skm=SrT/(xT+SrT/S)=14(MVA)Sq=1/(1/SqM+Xl/U2m)=0.292uqM=0.980*Sq/SqM=0.980*0.307/0.322=0.89uqM=0.983*Sq/SqM=0.983*0.2386/0.262=0.90故电机功率为30KW三相鼠笼异步电机可直接启动。(2)选用电机为30KW三相鼠笼异步电机(SqM=0.322MVA)。Xl=(0.07+6.3/185)*2*0.15+(0.07+6.3/25)*0.05=0.031+0.016=0.047Qfh=0.302uqm=(Skm+Qfh)/(Skm+Qfh+Sq)=14.302/14.597=0.980