谐波电流的危害有（）。A.使电机、变压器等电气设备产生附加损耗

搜题请搜索小程序“爱下问搜题”

问题单项选择题

谐波电流的危害有（）。

A.使电机、变压器等电气设备产生附加损耗、加速绝缘老化、噪声加大、效率降低、缩短使用寿命

B.在某一谐波频率下，电容器组与电力系统可能发生危险的并联谐振，引起很高的谐波电压

C.产生脉动转矩，引起电机角速度脉动，严重时会发生机械共振

D.减少测量仪表的误差

答案

参考答案：D

选择题

查看答案

单项选择题

People often do not make decisions by using the basic economic principle of rationally weighing all possibilities and then making the choice that can be expected to maximize benefits and minimize harm. Routinely, people process information in ways that are irrational in this sense.
Any of the following, if true, would provide evidence in support of the assertions above EXCEPT:

A．People tend to act on new information, independent of its perceived relative merit, rather than on information they already have.

B．People prefer a major risk taken voluntarily to a minor one that has been forced on them, even if they know that the voluntarily taken risk is statistically more dangerous.

C．People tend to take up potentially damaging habits even though they have clear evidence that their own peers as well as experts disapprove of such behavior.

D．People avoid situations in which they could become involved in accidents involving large numbers of people more than they do situations where single-victim accidents are possible, even though they realize that an accident is more likely in the latter situations than in the former.

E．(E) People usually give more weight to a physician’s opinion about the best treatment for a disease than they do to the opinion of a neighbor if they realize that the neighbor is not an expert in disease treatment.

查看答案