75KW减压起动柜毕业设计

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1、 毕业设计论文毕业设计论文 论文题目：论文题目：75KW 减压起动柜 系 部： 电气工程系 专 业： 电机与电器 班 级： 电 器 1 摘要摘要 电机的起动电流近似的与定子的电压成正比，对于因直接起动冲击电流过大 而无法承受的场合，要采用降低定子电压的办法来限制起动电流，这就是降压起 动。此时，起动转矩下降，起动电流也下降，所以只适合必须减小起动电流， 又 对起动转矩要求不高的场合。常见降压起动方法：定子串电阻降压起动、Y/ 起 动控 制线路、延边三角起动、软启动和自耦变压器降压起动。本产品是采用自耦 变压器降压启动的方法来设计的。 降压启动他是以牺牲功率为代价来换取降低启动电流来实现的。所以

2、不 能一概而以电机率的大小来确定是否需采用降压启动，还得看是什么样的负 载，一般在需要启动时负载轻运行时负载重尚可采用降压启动，一般情况下 鼠笼型电机的启动电流是运行电流的 57 倍，而对电网的电压要求一般是正 负 10%为了不形成对电网电压过大的冲击所以要采用降压启动，一般要求在 鼠笼型电机的功率超过变压器额定功率的 10%时就要采用降压启动。只有鼠 笼型电机才采用降压启动。 关键词： 三相异步电动机、自耦变压器、降压启动、启动方法 ABSTRACT Motor starting current of stator voltage approximate with direct propor

3、tion, so to reduce the stator voltage way to limit the starting current, is step-down start. Due to excessive current direct starting shock and could not afford the occasion, usually with step-down start by, at this time, starting torque drop, starting current decline, so only suitable for must redu

4、ce starting current, and the demand is not high starting torque of the occasion. Common step-down start methods: of the stator resistance step-down start, Y/ start control system in yanbian triangle line, starting, soft start-up and self cou pling transformer step-down start. Step-down start his exp

5、ense the cost of power in exchange for reduced starting current to fulfill. So cant all electrical and the chance of whether to determine the size of the necessary step-down start, will have to see what kind of load, generally in the need to start running negative heavy load light can start using st

6、ep-down, usually the squirrel-cage motor starting current is to run the current 5-7 times, and the requirements for grid voltage is plus or minus 10% general in order not to the formation of the network voltage big impact so to make use of the buck start, general requirement in the 2 squirrel-cage motor power more than 10% of the rated power transformer, be about to start the buck. Only the squirrel-cage motor used only step-down start. Keywords: three-phase asynchronous motor, Since