论文部分内容阅读
目前工地临时布设供电线路时,选用的导线截面“非大即小”。当选用的导线截面过大时,则造成不应有的浪费;当选用的导线截面过小时,由于异步电动机的启动电流比额定电流高4—7倍,大电流启动会给临时供电系统产生大幅度的电压降,电压过低电机就会严重过载,难以正常工作,当绝缘导线的最高工作温度超过65摄氏度时,导线的绝缘保护层受到破坏,绝缘程度降低,会造成火灾及人身伤亡事故。为确保施工工地供电安全和正常施工,工地临时供电要按以下方法认真计算。 1.电源选择工地临时用电电源的供给通常有以下几种情况: ①完全由工地附近的电力系统供给; ②工地附近的电力系统只供给一部分,工
Currently laid temporary power supply lines on the site, the selection of the wire cross-section “big big or small ”. When the selected wire cross-section is too large, resulting in unnecessary waste; when the selected wire cross-section is too small, due to asynchronous motor starting current is higher than the rated current 4-7 times, high current start will give temporary power supply system Amplitude voltage drop, the voltage is too low, the motor will be a serious overload, it is difficult to work properly when the maximum working temperature of the insulated wire exceeds 65 degrees Celsius, the wire insulation protection layer is damaged, reducing the insulation will cause fire and personal injury. To ensure the safety and normal construction of power supply construction site, temporary power supply to be calculated according to the following methods. 1. Power supply options Temporary power supply at construction sites is usually provided in the following situations: (1) it is entirely supplied by the power system in the vicinity of the site; (2) only part of the power system