【简答题】异步电动机拖动额定负载运行时,若电网电压过高或过低,会产生什么后果 ? 为什么 ?
【简答题】异步电动机拖动额定负载运行时,若电网电压过高或过低,会产生什么后果?为什么?
【判断题】邮轮客舱设计的因素: 1、邮轮的定位; 2、邮轮的经济效益; 3、宾客需求;
【多选题】After Effects6.5新增支持几种视频格式,便于和其他后期软件更好地整合,以下对新增格式的说法哪些是正确的?()
A.
Windows平台上运行的After Effects6.5支持输MPEG-2编码格式,更加简化了DVD的制作
B.
新增支持OMF(Open Media Framework)文件格式的导入和输出
C.
专业版还支持导入AAF(Advanced Authoring Format)文件格式,通过这种格式After Effects6.5可以和Adobe Premiere Pro 1.5交互使用时间线、编辑、关键帧等其他数据
【简答题】异步电动机拖动额定负载运行时,若电网电压过高或过低,会产生什么后果?为什么?
【简答题】一台三相4极、星形联结的异步电动机,额定值为:P N =1.7kW,U N =380V,I N =3.9A,n N =1445r/min。今拖动一恒转矩负载T L =11.38N·m连续运行,此时定子绕组平均温升已达到绝缘材料允许的温度上限。若电网电压下降为300V,在上述负载下电动机的转速为1400r/min,求此时电动机的铜耗为原来的多少倍?在此电网电压下该电动机能否长期运行下去(忽略励磁电流...
【单选题】_______tomorrow, we will still join hands to help the poor in the outside.
A.
However the weather is like
B.
However is the weather like
C.
Whatever is the weather like
D.
Whatever the weather is like
【简答题】We often talk about the weather. If we want to know about the weather, we can turn on the radio and 小题1: the weather report. We can also turn on the TV and watch the Weather 小题2: . And we can ask othe...
【简答题】阅读理解。 We often talk about the weather. If we want to know about the weather, we can turn on the radio and listen to the weather report. We can also turn on the TV and watch the Weather Show. We can ju...