《电机与拖动(专科)》武汉理工大学20春作业二

电机与拖动(专科)-作业二
1.[判断题] 三相异步电动机在轻载运行时,适当的降低电源电压,可以起到降低损耗,提高效率和功率因数的目的。
奥鹏作业答案可以联系Q  Q
    A.正确
    B.错误
    正确答案:——A——
2.[判断题] 直流电机实质上是一台带有换向器的交流电机。
    A.正确
    B.错误
    正确答案:——A——
3.[判断题] 电机在调速时,静差率越大,相对稳定性越好。
    A.正确
    B.错误
    正确答案:——B——
4.[判断题] <p class="MsoNormal" align="left" style="margin-bottom:7.5pt;text-align:left;  mso-pagination:widow-orphan;background:white"<span style="mso-bidi-font-size:  10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"采用电动机惯例的一台他励直流电动机</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext;position:relative;  top:6.0pt;mso-text-raise:-6.0pt"  <!--[if gte vml 1]<v:shape id="对象_x0020_20"   o:spid="_x0000_i1034" type="#_x0000_t75" style='width:100.2pt;height:18pt'   ole=""   <v:imagedata src="djytdpdt.files/image017.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="134" height="24" v:shapes="对象_x0020_20" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image018.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_20"    DrawAspect="Content" ObjectID="_1617439817"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"则电动机运行于倒拉反转状态。</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext;mso-font-kerning:0pt"  <o:p</o:p</span

    A.正确
    B.错误
    正确答案:————
5.[判断题] 只要电磁转矩等于负载转矩,电力拖动系统就能在某一转速下平衡稳定的运行。
    A.正确
    B.错误
    正确答案:————
6.[判断题] <p class="MsoNormal" align="left" style="margin-bottom:7.5pt;text-align:left;  mso-pagination:widow-orphan;background:white"<span style="mso-bidi-font-size:  10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"单相变压器原</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext"/</span<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";  mso-hansi-font-family:"Times New Roman";color:windowtext"副绕组的标志方式不仅与绕组的绕制方式有关,还与绕组的首端</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext"A</span<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";  mso-hansi-font-family:"Times New Roman";color:windowtext"(</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext"a</span<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";  mso-hansi-font-family:"Times New Roman";color:windowtext")和尾端</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext"X(<span style="position:relative;top:3.0pt;mso-text-raise:-3.0pt"   <!--[if gte vml 1]<v:shape   id="对象_x0020_48" o:spid="_x0000_i1048" type="#_x0000_t75" style='width:10.2pt;   height:10.8pt' ole=""   <v:imagedata src="djytdpdt.files/image045.wmz" o:title=""/  </v:shape<![endif]--   <!--[if !vml]--<img width="14" height="14" v:shapes="对象_x0020_48" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image046.png"   <!--[endif]--   <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_48"    DrawAspect="Content" ObjectID="_1617439831"   </o:OLEObject  </xml<![endif]--</span)</span<span style="mso-bidi-font-size:10.5pt;  font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"有关。</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext;mso-font-kerning:0pt"  <o:p</o:p</span

    A.正确
    B.错误
    正确答案:————
7.[判断题] 直流发电机电枢导体感应电动势和电流都是直流电。
    A.正确
    B.错误
    正确答案:————
8.[判断题] 他励直流电动机采用电枢电压反接制动迅速停车,位能性负载,当n=0时不断开电源,电机最后稳定运行在回馈制动状态。
    A.正确
    B.错误
    正确答案:————
9.[判断题] 直流发电机中电枢绕组只产生感应电动势,不产生电磁转矩。
    A.正确
    B.错误
    正确答案:————
10.[判断题] <p class="MsoNormal" align="left" style="margin-bottom:7.5pt;text-align:left;  mso-pagination:widow-orphan;background:white"<span style="mso-bidi-font-size:  10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"由变压器一相电动势表达式</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext;position:relative;  top:6.0pt;mso-text-raise:-6.0pt"  <!--[if gte vml 1]<v:shape id="对象_x0020_30"   o:spid="_x0000_i1038" type="#_x0000_t75" style='width:90pt;height:19.2pt'   ole=""   <v:imagedata src="djytdpdt.files/image025.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="120" height="26" v:shapes="对象_x0020_30" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image026.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_30"    DrawAspect="Content" ObjectID="_1617439821"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"可知,</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;  color:windowtext;position:relative;top:5.0pt;mso-text-raise:-5.0pt"  <!--[if gte vml 1]<v:shape   id="对象_x0020_31" o:spid="_x0000_i1039" type="#_x0000_t75" style='width:13.8pt;   height:18pt' ole=""   <v:imagedata src="djytdpdt.files/image027.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="18" height="24" v:shapes="对象_x0020_31" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image028.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_31"    DrawAspect="Content" ObjectID="_1617439822"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"相量落后于</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext;position:relative;top:6.0pt;mso-text-raise:-6.0pt"  <!--[if gte vml 1]<v:shape   id="对象_x0020_32" o:spid="_x0000_i1040" type="#_x0000_t75" style='width:19.2pt;   height:19.2pt' ole=""   <v:imagedata src="djytdpdt.files/image029.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="26" height="26" v:shapes="对象_x0020_32" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image030.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_32"    DrawAspect="Content" ObjectID="_1617439823"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"相量</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;  color:windowtext"90<sup0</sup</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext;mso-font-kerning:0pt"  <o:p</o:p</span

    A.正确
    B.错误
    正确答案:————
11.[判断题] <p class="MsoNormal" align="left" style="margin-bottom:7.5pt;text-align:left;  mso-pagination:widow-orphan;background:white"<span style="mso-bidi-font-size:  10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"额定电压为</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext"  <!--[if gte vml 1]<v:shapetype   id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t"   path="[email protected]@[email protected]@[email protected]@[email protected]@5xe" filled="f" stroked="f"   <v:stroke joinstyle="miter"/   <v:formulas    <v:f eqn="if lineDrawn pixelLineWidth 0"/    <v:f eqn="sum @0 1 0"/    <v:f eqn="sum 0 0 @1"/    <v:f eqn="prod @2 1 2"/    <v:f eqn="prod @3 21600 pixelWidth"/    <v:f eqn="prod @3 21600 pixelHeight"/    <v:f eqn="sum @0 0 1"/    <v:f eqn="prod @6 1 2"/    <v:f eqn="prod @7 21600 pixelWidth"/    <v:f eqn="sum @8 21600 0"/    <v:f eqn="prod @7 21600 pixelHeight"/    <v:f eqn="sum @10 21600 0"/   </v:formulas   <v:path o:extrusionok="f" gradientshapeok="t" o:connecttype="rect"/   <o:lock v:ext="edit" aspectratio="t"/  </v:shapetype<v:shape id="对象_x0020_5" o:spid="_x0000_i1025" type="#_x0000_t75"   style='width:54pt;height:13.8pt' o:ole=""   <v:imagedata src="djytdpdt.files/image001.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="72" height="18" v:shapes="对象_x0020_5" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image002.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_5"    DrawAspect="Content" ObjectID="_1617439807"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"的单相变压器,短路阻抗</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext"  <!--[if gte vml 1]<v:shape id="对象_x0020_6" o:spid="_x0000_i1026"   type="#_x0000_t75" style='width:97.8pt;height:18pt' o:ole=""   <v:imagedata src="djytdpdt.files/image003.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="130" height="24" v:shapes="对象_x0020_6" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image004.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_6"    DrawAspect="Content" ObjectID="_1617439808"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext",负载阻抗为</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext"  <!--[if gte vml 1]<v:shape id="对象_x0020_7" o:spid="_x0000_i1027"   type="#_x0000_t75" style='width:93pt;height:16.8pt' o:ole=""   <v:imagedata src="djytdpdt.files/image005.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="124" height="22" v:shapes="对象_x0020_7" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image006.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_7"    DrawAspect="Content" ObjectID="_1617439809"   </o:OLEObject  </xml<![endif]--,</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"从一次侧看进去总阻抗大小为</span<span lang="EN-US" style="mso-bidi-font-size:  10.5pt;color:windowtext"  <!--[if gte vml 1]<v:shape id="对象_x0020_8" o:spid="_x0000_i1028"   type="#_x0000_t75" style='width:70.8pt;height:16.2pt' o:ole=""   <v:imagedata src="djytdpdt.files/image007.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="94" height="22" v:shapes="对象_x0020_8" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image008.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_8"    DrawAspect="Content" ObjectID="_1617439810"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"。</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;  color:windowtext;mso-font-kerning:0pt"  <o:p</o:p</span

    A.正确
    B.错误
    正确答案:————
12.[判断题] 若要改变异步电动机的转向,可以改变定子绕组中三相电流的相序来实现。
    A.正确
    B.错误
    正确答案:————
13.[判断题] 在三相异步交流电动机中,如果将绕组三出线头中任二个接头换接一下,电机将反方向旋转。
    A.正确
    B.错误
    正确答案:————
14.[判断题] <p class="MsoNormal" align="left" style="margin-bottom:7.5pt;text-align:left;  mso-pagination:widow-orphan;background:white"<span style="mso-bidi-font-size:  10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:  "Times New Roman";color:windowtext"三相异步电动机的电磁功率</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext;position:relative;  top:5.0pt;mso-text-raise:-5.0pt"  <!--[if gte vml 1]<v:shape id="对象_x0020_35"   o:spid="_x0000_i1041" type="#_x0000_t75" style='width:55.2pt;height:16.8pt'   o:ole=""   <v:imagedata src="djytdpdt.files/image031.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="74" height="22" v:shapes="对象_x0020_35" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image032.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_35"    DrawAspect="Content" ObjectID="_1617439824"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext;position:relative;top:5.0pt;mso-text-raise:-5.0pt",</span<span style="mso-bidi-font-size:10.5pt;font-family:Microsoft Yahei;mso-ascii-font-family:"Times New Roman";  mso-hansi-font-family:"Times New Roman";color:windowtext"机械功率</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;color:windowtext;position:relative;  top:6.0pt;mso-text-raise:-6.0pt"  <!--[if gte vml 1]<v:shape id="对象_x0020_36"   o:spid="_x0000_i1042" type="#_x0000_t75" style='width:52.8pt;height:18pt'   o:ole=""   <v:imagedata src="djytdpdt.files/image033.wmz" o:title=""/  </v:shape<![endif]--  <!--[if !vml]--<img width="70" height="24" v:shapes="对象_x0020_36" src="http://wljy.whut.edu.cn:80/uploadfiles/word/djytdpdt.files/image034.png"  <!--[endif]--  <!--[if gte mso 9]<xml   <o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="对象_x0020_36"    DrawAspect="Content" ObjectID="_1617439825"   </o:OLEObject  </xml<![endif]--</span<span style="mso-bidi-font-size:10.5pt;font-family:  宋体;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";  color:windowtext"。</span<span lang="EN-US" style="mso-bidi-font-size:10.5pt;  color:windowtext;mso-font-kerning:0pt"  <o:p</o:p</span

    A.正确
    B.错误
    正确答案:————
15.[判断题] 直流电动机反接制动过程的机械特性一定是一条过原点的直线。
    A.正确
    B.错误
    正确答案:————
16.[判断题] 一台他励直流发电机,当磁极固定,电刷与电枢同时旋转时,电刷两端的电压是直流电压。
    A.正确
    B.错误
    正确答案:————
17.[判断题] 改变并励直流电动机电源的极性,电动机旋转方向反向。
    A.正确
    B.错误
    正确答案:————
18.[判断题] 他励直流发电机的效率一直随着负载电流的增大而增大。
    A.正确
    B.错误
    正确答案:————
19.[判断题] 一台变压器原设计的频率为50HZ,现将它接到60HZ的电网上运行,当额定电压不变时,铁芯中的磁通将减少。
    A.正确
    B.错误
    正确答案:————
20.[判断题] 直流发电机电刷位于几何中心线上,若磁路不饱和,这时仅产生交轴电枢反应。
    A.正确
    B.错误
    正确答案:————
21.[单选题] 直流电机电枢反应导致合成磁密为零的地方偏离了空载时的(   )
    A.磁极中心线上
    B.物理中性线上
    C.几何中性线上
    正确答案:————
22.[单选题] 他励直流电动机降低电枢电压的人为特性的特点为(     )
    A.特性直线的斜率与电压成正比变化
    B.理想空载转速不变
    C.斜率不变
    正确答案:————
23.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;line-height:20.0000pt;mso-line-height-rule:exactly;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"一台变单相压器在高压边做空载实验求得的励磁参数和在低压边做空载实验求得的参数应(    )。假设</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="230" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD36321.png"</span.<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    A.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"大</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:3.0000pt;mso-text-raise:-3.0000pt;"<img width="50" height="54" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD36433.png"</span倍 <span style="mso-spacerun:'yes';font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"          </span<span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    B.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"小</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:3.0000pt;mso-text-raise:-3.0000pt;"<img width="50" height="54" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD36556.png"</span             <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    C.一样大
    正确答案:————
24.[单选题] 变压器的电源电压不变,随着负载减少到空载,主磁通将(  )
    A.随之增大
    B.随之减少
    C.先减少后增大
    D.基本不变
    正确答案:————
25.[单选题] 他励直流电动机的人为特性与固有特性相比,其理想空载转速和斜率均发生了变化,那么这条人为特性一定是(          )。
    A.串电阻的人为特性;
    B.降压的人为特性;
    C.弱磁的人为特性
    正确答案:————
26.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;line-height:20.0000pt;mso-line-height-rule:exactly;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"关于三相异步电动机转子边产生的磁动势</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="50" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD30744.png"</span的旋转速度说法正确的是( <span style="mso-spacerun:'yes';font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  </span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;")</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    A.<p class="MsoNormal" style="display:inline;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"相对定子边磁动势</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="44" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD30878.png"</span <span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"静止 </span<span style="mso-spacerun:'yes';font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"    </span<span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    B.相对定子静止
    C.相对转子静止
    正确答案:————
27.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;line-height:20.0000pt;mso-line-height-rule:exactly;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"三相绕线式异步电机定子边电压降低时,最大转矩</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="50" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD19805.png"</span和临界转差率<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="54" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD19919.png"</span <o:p</o:p

    A.增大、不变
    B.增大、变小
    C.变小、不变
    D.变小、增大
    正确答案:————
28.[单选题] 异步电动机等效电路中的励磁电抗Xm为(  )
    A.漏磁通引起的电抗
    B.基波旋转磁通引起的电抗
    C.铁耗产生的电抗
    正确答案:————
29.[单选题] <p class="MsoNormal" style="line-height:20.0000pt;mso-line-height-rule:exactly;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"变压器主磁通</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="50" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD18138.png"</span的主要特征是:<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span
    q1 6 4 7 861640
    A.一个幅值恒定的旋转磁场
    B.一个幅值变化的旋转磁场
    C.一个幅值变化,位置不变的脉动磁场
    D.必须在自定义函数后面
    正确答案:————
30.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"一台他励直流发电机的输入功率</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="40" height="59" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD39625.png"</span等于( <span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;" </span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;")</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    A.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="148" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD39741.png"</span           <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    B.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:12.0000pt;mso-text-raise:-12.0000pt;"<img width="157" height="99" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD39862.png"</span           <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    C.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="103" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD39983.png"</span <o:p</o:p

    正确答案:————
31.[单选题] 并联运行时,变压器短路阻抗越小,则该变压器流过的电流( )。
    A.越小
    B.越大
    C.不变
    正确答案:————
32.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;line-height:20.0000pt;mso-line-height-rule:exactly;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"单相变压器磁路饱和时,主磁通</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="35" height="54" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD28530.png"</span和励磁电流<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="38" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD28643.png"</span的波形( <span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;" </span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;")</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    A.同时为正弦波
    B.同为尖顶波
    C.不会同时为正弦波
    正确答案:————
33.[单选题] 他励直流电动机拖动位能性恒转矩负载,采用降压调速的方法,当转速降低时,电枢电流不变,输入功率
    A.增大
    B.不变
    C.减小
    正确答案:————
34.[单选题] 自耦变压器的绕组容量与变压器容量的关系是(   )。
    A.<p class="MsoNormal" style="margin-right:0.0000pt;mso-para-margin-right:0.0000gd;mso-para-margin-left:0.0000gd;mso-layout-grid-align:none;layout-grid-mode:char;text-autospace:ideograph-numeric;mso-pagination:none;" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:15.0000pt;mso-text-raise:-15.0000pt;"<img width="279" height="113" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD25960.png"</span      <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    B.<p class="MsoNormal" style="margin-right:0.0000pt;mso-para-margin-right:0.0000gd;mso-para-margin-left:0.0000gd;mso-layout-grid-align:none;layout-grid-mode:char;text-autospace:ideograph-numeric;mso-pagination:none;" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="235" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD26076.png"</span     <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    C.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:15.0000pt;mso-text-raise:-15.0000pt;"<img width="273" height="113" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD26191.png"</span <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    正确答案:————
35.[单选题] 一台三相变压器的额定电压U1N/U2N=10000/400V,绕组为Y/Δ—11接法,则其变比为
    A.14.43
    B.25
    C.43.3
    正确答案:————
36.[单选题] 直流电机的气隙磁动势是由(       )产生的
    A.励磁磁动势
    B.电枢磁动势
    C.励磁磁动势和电枢磁动势
    正确答案:————
37.[单选题] 当电动机的电枢回路铜损耗比电磁功率或机械功率都大时,这时电动机处于
    A.电压反接的反接制动状态
    B.能耗制动状态
    C.倒拉反转制动状态
    D.回馈制动状态
    正确答案:————
38.[单选题] 变压器副边额定电压是变压器原边加额定电压,副边(   )
    A.空载相电压
    B.空载线电压
    C.额定负载相电压
    D.额定负载线电压
    正确答案:————
39.[单选题] <p class="MsoNormal" style="margin-left:0.0000pt;mso-para-margin-left:0.0000gd;text-indent:0.0000pt;mso-char-indent-count:0.0000;"<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"一台三相6极电动机,每极每相槽数q=3,则定子总槽数Z</span<sub<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;vertical-align:sub;"1</span</sub<span style="mso-spacerun:'yes';font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"和极距</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:3.0000pt;mso-text-raise:-3.0000pt;"<img width="35" height="38" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD38712.png"</span分别为( <span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;" </span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;")</span<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    A.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="328" height="59" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD38829.png"</span <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    B.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="328" height="59" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD38940.png"</span  <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    C.<p class="MsoNormal" style="display:inline;"<span style="font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:5.0000pt;mso-text-raise:-5.0000pt;"<img width="328" height="59" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD39052.png"</span <o:p</o:p

    正确答案:————
40.[单选题] 关于他励直流发电机功率关系说法正确的是:(          )。
    A.<p class="MsoNormal" style="line-height:20.0000pt;mso-line-height-rule:exactly;" style="display:inline;"<span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="235" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD12038.png"</span <o:p</o:p

    B.<p class="MsoNormal" style="line-height:20.0000pt;mso-line-height-rule:exactly;" style="display:inline;"<span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="215" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD12148.png"</span  <span style="font-family:Microsoft Yahei;font-size:12.0000pt;mso-font-kerning:1.0000pt;"  <o:p</o:p</span

    C.<p class="MsoNormal" style="display:inline;"<span style="font-family:'Times New Roman';mso-fareast-font-family:Microsoft Yahei;font-size:10.5000pt;mso-font-kerning:1.0000pt;position:relative;top:6.0000pt;mso-text-raise:-6.0000pt;"<img width="247" height="60" src="http://wljy.whut.edu.cn:80/uploadfiles/word/DJYTD.files/DJYTD12260.png"</span <o:p</o:p

    正确答案:————


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