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三相异步电机软启动设计 总被引:1,自引:0,他引:1
介绍了三相异步电机的软启动工作原理及各种负载下的启动方式,并分析了这几种软启动方式的优缺点,给出以ATS48D62Q为软启动器的电机软启动设计方案,比较在软启动和直接启动电机方式下的电机电流状况. 相似文献
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介绍了软起动器技术组成,在船舶电动机采用软启动器减小了电机频繁起动对系统的冲击,克服了启动电流过大、启动时间过长对电机造成的损害。 相似文献
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文章叙述了交流电机直接起动存在的弊端与危害,设计了智能型电机启动器,系统结构采用可变电抗器来隔离高压和低压,实现电机软启动。控制器采用九点控制思想,使启动电流在整个启动过程无瞬间冲击且能连续变化。试验表明,启动器能有效地控制启动电流,具有一定的应用价值。 相似文献
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某船艏侧推器电机启动困难实例 总被引:1,自引:0,他引:1
<正>0引言为增强船舶的操纵灵活性,现在很多船舶都装配侧推装置,这些侧推装置大多采用电机带动调距桨(CPP)的形式,使用的常规动力三相电源(50 Hz、400 V)大多由柴油发电机或主机带动的轴带发电机供给。必须限制电机启动电流,否则启动电流过大容易影响电网稳定,导致电机启动失败甚至烧毁电机。1 故障现象某船的艏侧推器电机三相为380 V、385 kW、50 Hz,经常出现启动失败、主配电板上艏侧推器主开关脱扣甚至轴带发电机主 相似文献
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王守海 《船舶标准化工程师》2019,52(2)
针对某船舵机启动箱断路器频繁跳闸的故障现象,对断路器自身状态、电机正常起动时的电流冲击、电机瞬间断电再上电及电网压降等因素进行了分析,给出了有效的解决方案。为今后此类问题的解决及相关设计提供借鉴和参考。 相似文献
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介绍了我国港口资源的整合现状,指出港口整合可以提升港口的形象和地位,也为区域经济和城市的发展注入强大的动力。最后指出在港口资源整合中要避免的几个问题。 相似文献
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广州集装箱码头的轮胎式场桥小车制动器使用10多年后,出现了许多问题,故进行了改造.分析了轮胎式集装箱龙门起重机小车制动器的主要故障现象,提出了改造方案,并加以实施. 相似文献
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本文对现有的选定球面轴承的三种工程方法进行了分析比较.引入了“合力系数”,并给出了合力方向上投影面积的精确解. 相似文献
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分析柴油机故障中常见的机体裂纹故障原因,认为由于设计缺陷和管理及操作不当,易造成船舶柴油机缸体上的裂纹多发生在气缸套凸肩处。如不及时处理这些裂纹和故障,就会造成缸套的裂纹直至出现缸套漏水等严重后果,针对NANTAIQUEEN轮柴油机对该类型故障的检修提出具体措施。 相似文献
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The hydrophysical and hydrochemical structure of the Sea of Azov, with developed bottom anoxia, was studied during the RV “Akvanavt” cruise from July 31 to August 03, 2001. The anoxic zone with a thickness from 0.5 to 4 m above the bottom was found in all deep regions of the Sea. Concentrations of hydrochemical parameters were similar to the pronounced anoxic conditions (about 90 mmol m− 3 of hydrogen sulfide, 17 mmol m− 3 of ammonia, 6 mmol m− 3 of phosphate, 7 mmol m− 3 of total manganese). The hydrophysical structure was characterized by the uniform distribution of temperature in the upper 6–7 m mixed layer (UML). Below this a thin (0.4–0.8 m) thermocline layer was observed, just above the anoxic waters. Formation of this phenomenon was connected with that summer weather conditions. Intensive rains led to increased influx of river waters in June. That resulted in large input of allochtonous organic matter (OM) and inorganic nutrients; the latter were consumed on the additional autochthonous organic matter production. In July the weather was characterized by a significant rise in the daily averaged air temperature and large oscillations of temperature during the day. In this period a wind of constant direction was absent, but wind bursts were observed. The completed analyses showed that the formation of such a structure could be connected with the following factors: (i) positive growth trends of the daily averaged temperature and the daily oscillations of temperature, (ii) presence of wind bursts. The joint action of these factors resulted in the formation of the UML. The amplitude of wind bursts determined the depth of UML, and the value of trend determined the value of the temperature change in the thermocline. An initial presence of bottom halocline (caused by the Black Sea water influx to the bottom of the Sea of Azov) prevented the heating of the bottom layer and therefore led to an increase of vertical gradient of temperature in the thermocline. The spatial distribution of the turbulent exchange coefficient confirmed the existence of a “stagnation” area located above the anoxia zone, which is also, apparently, the reason for its occurrence. 相似文献
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