一臺三相繞線轉(zhuǎn)子異步電動機的額定值為:PN=150KW,UN=380V,λm=2.6,nN=1455r/min,E2N=213V,I2N=420A.。試求: ①起動轉(zhuǎn)矩Tst=? ②若使起動轉(zhuǎn)矩增大一倍,轉(zhuǎn)子每相繞組應(yīng)串多大電阻?