【单选题】一个具有2对极的异步电机,其同步转速为( )r/min
【简答题】一台四速笼型异步电动机的4个同步转速为:n s1 =3000r/min,n s2 =1500r/min,n s3 =1000r/min,n s4 =500r/min。试计算在下列两种空载分级起动的情况下,起动到最大转速时电动机的能量损耗: (1)两级起动:先由n=0到n s2 =1500r/min,而后到n s1 =3000r/min; (2)三级起动:先由n=0到n s3 =1000r/min,...
【简答题】一台四速笼型异步电动机的4个同步转速为:n s1 =3000r/min,n s2 =1500r/min,n s3 =1000r/min,n s4 =500r/min。,由最高转速空载逐级制动,试计算电机的能量损耗:
【简答题】The president promised to keep all the board /?The president promised to keep all the board members _________ of how the negotiations were going on. A) inform B) informing C) be inf...
【简答题】The president promised to keep all the board members ______ of the negotiations.(inform)
【简答题】The typical problems that exist in the board of Japanese Company include all the following EXCEPT( )