电压负反馈调速系统,在低速运行时容易发生停转现象,主要原因是电压...
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Friday, September 16, 2022
三相异步电动机转子旋转后,在转子中感应出电动势及电流,其频率f<...
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国家电网公司员工道德规范要求,在优质服务中,要坚持()、()、(...
Friday, September 16, 2022
Sunday, September 11, 2022
Thursday, September 15, 2022
Sunday, September 11, 2022
若两个正弦交流电压反相,则这两个交流电压的相位差是()。...
Sunday, September 11, 2022
时间继电器的种类很多,常用的主要有()、()、()和()等。...
Friday, September 16, 2022
在三相四线制中,当采用了漏电保护时,其开关后的零线()进行重复接...
Friday, September 16, 2022
直流电动机在额定负载下运行时,其换向火花应不超过()。...
Friday, September 16, 2022
Friday, September 16, 2022
Sunday, September 11, 2022
反时限过电流保护的动作时间与故障电流的大小有()关系。A、正比B、反比C、直线...
Wednesday, December 6, 2023
Sunday, September 11, 2022
SCR—D拖动方式直流电梯比F—D拖动方式直流电梯节能。...
Friday, September 16, 2022
Friday, September 16, 2022
Friday, September 16, 2022
Friday, September 16, 2022
Sunday, September 11, 2022