问题 问答题

—台具有四个磁极的三相异步电动机,其额定电压为380V,额定电流为75A,额定功率为40kW,采用三角形接法。在额定负载下运行时,其转差率为0.02。电动机的TO/TN=1.2IO/IN=6.5。试求进行星形一三角形联结起动时的起动电流和起动转矩.

答案

参考答案:

对于4极电动机,P=2,依式n1=,得

依式,得n=n1(1-S),代入数据得

n=1500(1-0.02)r/min=1470r/min

依式,得Tn=9550×≈259.86N·m在采用星形白三角形联结起动的情况下,则有

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A firm handshake is key to interview success. As any serious job-hunter knows, it helps to dress smartly and smile at that all-important interview. But research has showed that a firm handshake is what really matters when it comes to impressing potential employers.

The US research looked at 98 undergraduates taking part in mock (模拟) interviews with businesses. As each undergraduate was graded on their overall performance, five "handshake raters" also marked them on their grasp, strength, duration, vigor and eye contact.

Professor Greg Stewart, from the University of Iowa, who led the study, said those who scored highly with the handshake raters were also considered to be the most hirable by the interviewers. Students with " wimpy" shakes were judged to be more timid and less impressive.

The study also found women with a firm handshake were likely to be evaluated more favorably than their male counterparts.

Professor Stewart said: "We've always heard that interviewers make up their mind about a person in the first two or three minutes of an interview. But we found that the first impression begins with a handshake that sets the tone for the rest of the interview. We don't consciously remember a person's handshake but it is one of the first non-verbal clues we get about the person's overall personality, and that impression is what we remember."

Women were less likely to have a highly rated handshake, partly because traditionally they shake hands less than men. But when women did possess a firm handshake, they were likely to be evaluated more favorably than their male counterparts.

Body language experts warn, however, that the firmness needs to be just right, - as an over enthusiastic "bone crusher" handshake can indicate self-importance, a controlling personality and a lack of trustworthiness.

The handshake is thought to have originated in medieval Europe as a way for kings and knights to show that they did not intend to harm each other and possessed no hidden weapons.

小题1:The passage is probably intended for ______.

A.job-hunters

B.an undergraduate

C.employers

D.handshake raters小题2:From the first paragraph we know that in an interview ______.

A.dressing smartly is more important than a firm handshake

B.smile has no effect on impressing potential employers

C.a firm handshake is more important than dressing smartly, and smile

D.dressing smartly, smile and a firm handshake are of the same importance小题3:Which of the following statements is NOT true according to the passage?

A.The firmer your handshake is the better impression you leave.

B.The undergraduates without a firm handshake are thought to be less impressive.

C.Generally speaking, women shake hands less with others.

D.It's said that the handshake dates back to medieval Europe.小题4:What is the main idea of the passage?

A.Women with a firm handshake were likely to leave a better impression than men.

B.A successful job interview starts with a firm handshake.

C.Dressing, smile and a firm handshake are all important to a successful job interview.

D.Job interview success depends on interviewees' body language.