断续或短时工作制电动机的设备功率,当采用需要系数法或二项式法计算时,是将额定功率统一换算到负载持续率为()时的有功功率。...
Thursday, September 15, 2022
变更接线或试验结束,应()试验电源,并将升压设备的高压部分放电、短路接地。...
Thursday, September 22, 2022
Thursday, September 22, 2022
消防控制、通信和警报线路采用暗敷设时,宜采用金属管或经阻燃处理的硬质塑料管保护,并应敷设在不燃烧体的结构层内,且保护层厚...
Thursday, September 22, 2022
Friday, September 16, 2022
Tuesday, September 20, 2022
问答题一380V三相线路,供电给下表所示4台电动机,计算该线路的尖峰电流。(Ijs=为起动电流与额定电流差值最大一台电动机的起动电流)...
Sunday, November 26, 2023
单选题声波传播时,媒质中的声阻抗是指()。A 声压与媒质体积速度之比B 声压与媒质质点速度之比C 声压与流阻之比D 声压与风阻之比...
Sunday, December 10, 2023
单选题通常配套电动机功率在()以下风机、水泵不采用调速装置。A 30kWB 25kWC 15kWD 不确定...
Friday, November 24, 2023
Thursday, September 22, 2022
保护配电柱上的断路器、负荷开关和电容器组等的避雷器,其接地线应与设备外壳相连,接地电阻不应大于()Ω。...
Monday, September 19, 2022
某车间AB、BC相电焊机均为47kW,功率因数为0.6,负载持续率为60%;需要系数为0.5;C相照明共6kW,功率因数...
Thursday, September 22, 2022
Thursday, September 22, 2022
Thursday, September 22, 2022
Monday, September 19, 2022
Thursday, September 22, 2022
Tuesday, September 20, 2022
单选题一类防雷建筑物防直击雷的避雷带网格尺寸不应大于()。A 10m×10mB 5m×5mC 3m×3mD 2m×2m...
Sunday, October 16, 2022
Wednesday, September 21, 2022
()可以避免静车时各放大器零漂引起可控硅整流电路有输出使电机爬行的不正常现象...
Thursday, September 15, 2022