符号√表示已修改 习题十一 1√解:1)p?60f60?50??1对极 n300060f60?502)n???54.55r/min
p55
2√ 解:(1)气隙磁密表达式为
b???B?vmsin??, ??1,3,5,7??
设转子处于图示位置时作为时间起点,t=0。???t
所以:e(0)?b?lv?l?v?1?B?e(?)?b?lv?l?v??B?vmsin??t, ??1,3,5,7??
vmsin(??t???1)??1,3,5,7??
(2)
p?360?2?360???20? 3 √解:??Z36 由于第1槽导体电势 e1?E1msin?t
所以第2槽导体电势 e2?E1msin(?t?20?)
第10槽导体电势 e10?E1msin(?t?9?20?)??E1msin?t 第19槽导体电势 e19?E1msin(?t?18?20?)?E1msin?t
e28?E1msin(?t?27?20?)??E1msin?t e36?E1msin(?t?35?20?)?E1msin(?t?20?)
习题十二
1√ 解:线匝电动势=线圈边感应电动势之差
ET?2E1cos15??2E1?0.9659?1.932E1
E1.932E1ky?T??0.966
2E12E1
2√ 解:1)绕组展开图
2)n? v?60f60?50??1500r/min p2?
?11.78m/s 6060 设t?0时刻导体1处于??0位置,各导体编号顺转子转向
?Dn??0.15?1500
ea1?b?1lv?0.1?11.78?(sin??0.3sin3??0.2sin5?)?1.178(sin?t?0.3sin3?t?0.2sin5?t)伏特
p?360?2?360???20? ?1?Z36nean?b?l?v =1.178{sin[?t?(n?1)?20]?0.3sin3[?t?(n?1)?20]
?? ?0.2sin5[?t?(n?1)?20?]}伏特Z36??3 3)q?2pm4?3 kq1q?13?20?sinsin0.522????0.959 8??10.520920qsin3?sin22q??13?3?20?sinsin22???0.666 7???13?20qsin3?sin22 kq3 kq5q??13?5?20?sinsin0.522????0.217 6???12.2985?20qsin3?sin22 单层绕组为整距绕组,ky1?ky3?ky5?1 整距线匝,
eT?2ea?2.356(sin??0.3sin3??0.2sin5?)?2.356(sin?t?0.3sin3?t?0.2sin5?t)?2.356(sin314t?0.3sin942t?0.2sin1570t)伏特 整距线圈,
ec?WceT?2.356?100(sin314t?0.3sin942t?0.2sin1570t)?235.6(sin314t?0.3sin942t?0.2sin1570t)伏特
线圈组,
eq?qek(qckq?3?235.61?678.39sint3?14
一相绕组,
sin?3t143kq0.3?sitn59qk420.2tsin?706.8(0.9598sti?n314?0.6667t?0.3si?n9.24s2in10.52t7107141.3t6?sin9423t0.伏特76sin1570e??4)
p2eq?eq?eq a2?678.39sin314t?141.36sin942t?30.76sin1570t伏特222E??E?1?E?3?E?5?(678.3922)2?(141.3622)2?(30.762)2?490.5V
22 El?3E?1?E?5?(678.39)2?(30.76)2?831.71V
pn1?3000??50HZ 6060Z30??5 q?2pm2?33√ 解:1)f?p?360?1?360???12? ?1?Z30 kq1q?15?12?sinsin0.522????0.9567 ??10.522612qsin5?sin22 整距绕组,ky1?1 所以: kw1?kq1?0.9567
E?1?4.44f1WkW1?1?4.44?50?20?0.9567?1.505?6392.9V
2)kq5q??15?5?12?sinsin0.522????0.2 ???12.55?12qsin5?sin22kw5?kq5?0.2
3)要消除五次谐波,y???15?14Z430????????12 ?552P52y4 短距后,ky1?sin(?90?)?sin(?90?)?0.951
?5E1?4.44f1W1kW1?1?ky1E?1 ?4.44?50?20?0.9567?0.951?1.505
?0.951?6392.9?6079.65V4)绕组展开图
4 √解:1)Z?2pqm?4?1?3?12槽,整距双层绕组
??
Z12??3,y???3,q?1 2p4
2)由于q?1,所以每个线圈组的电势=线圈电势。
由于为整距线圈, 线匝基波电势=2×导体基波电势=2×1=2伏,每槽有两个导体,所以每个线圈有1匝,所以线圈基波电势=2伏。
?8伏a?12p4?28?E线圈组1????4伏a?2 E?1?aaa??2伏a?43)对于整距线圈,五次谐波磁密在线圈的两个有效边上,感应的电势大小相等、方向相反,
所以整距线圈的五次谐波电势=2×有效边导体五次谐波电势
=2×0.2=0.4伏。
E?5?1.6伏a?12p4?0.41.6??E线圈组5????0.8伏a?2 aaa??0.4伏a?4a?1a?2 a?4或者 E?5?1.6??4.44f5W1kw5?5?4.44f5kW5?5?W1?0.4W1??0.8?0.4?
习题十三
1 √解:1)整距线圈 Fc??其中ky??sin? Fc1?4??21???IcWcsin?sin?t, 2?2?2??1
4??2?100?5sin?t?450.16sin?t安匝/极 2 Fc3??1Fc1sin?t??150.1sin?t安匝/极 312)i?2?5sin?t??2?5?sin3?t
3411f?(?)???i?Wc??ky?co??s?2?
??4?1?22?100?1?co??sky?(5?sti?n35?sti n3)5?90cos??ky?(5sin?t?sin3?t)?35f1(?)?90c?os(5?st?in?stin3) 3 ? (45?0ts?in1?5t0si?n3)cos5f3(?)??30co?s3(?5ts?in?tsin3) 3 ??(150sin?t?50sin3?t)cos3? 三次谐波电流可以产生在空间上分布的基波脉振磁动势,只是其脉振频率为基波电流产生的基波磁动势的三倍。 3)若通以5A直流电流,磁动势为幅值固定的矩形波。
4114111000??Ic?Wc?ky????5?10?0ky??k ?2??2???y?1000?318安匝/极 Fc1??1000??106安匝/极 Fc3??3? Fc??
习题十四
1 √解: fa1?F?m1sin?tcos?
fb1?F?m1sin(?t?120?)cos? fc1?F?m1sin(?t?240?)cos? f1?fa1?fb1?fc1?0 fa3?F?m3sin?tcos3? fb3?F?m3sin(?t?120?)cos3?
fc3?F?m3sin(?t?240?)cos3? f3?fa3?fb3?fc3?0
2 √解: fa1?F?m1sin?tcos?
fb1?F?m1sin?tcos(??120?) fc1?F?m1sin?tcos?(?24?0) f1?fa1?fb1?fc1?0 fa3?F?m3sin?tcos3?
fb3?F?m3sin?tcos3(??120?)?F?m3sin?tcos3? fc3?F?m3sin?tcos3(??240?)?F?m3sin?tcos3?
f3?fa3?fb3?fc3?3F?m3sin?tcos3?
3 解:1)fa1?F?m1sin?tcos? fb1?F?m1sin?tcos(??90?)
f1?fa1?fb1?F?m1sin?t[cos??cos(??90?)]??2F?m1sin?tcos(??45) fa3?F?m3sin?tcos3?
fb3?F?m3sin?tcos3(??90?)
2)fa1?F?m1sin?tcos?
fb1?F?m1sin(?t?90?)cos(??90?) ?F?m1(?cos?t)(?sin?)?F?m1cos?tsin?f3?f?a3?fb3Fms?3in?t[co?s?3?c?o?s3?(?2F?m3si?ntco?s?(3135)
90)]
f1?fa1?fb1?F?m1(sin?tcos??cos?tsin?)?F?m1sin(?t??)
fa3?F?m3sin?tcos3?
?90)c?o?s3(??90Fm)3?f3?fa3?fb3?F?m3(sin?tcos3??cos?tsin3?)
?F?m3sin(?t?3?) fb3?F?(?t?m3sin? s?tco?sin34√ 解:(1)解析法
由于合成基波磁势为圆形旋转 磁势,所以两相电流大小相等。
令ib?2Isin(?t??)
fa1?F?m1sin?tcos? F?m1 ?[sin(?t??)?sin(?t??)]2fb1?F?m1sin(?t??)cos(??120?) F?m1???[sin(?t?????120)?sin(?t?????120)]2已知反转磁动势为零,则 sin(?t??)?sin(?t?????120?)?0?
sin(?t??)=-sin(?t?????120?)?
???120??180????60
所以 ib?2Isin(?t?60?)
(2)矢量法
?t?90?时相量图如右, ?t???90??ib?Imax,
?t(90?)?60????90??ib?Imax
所以??60,ib?2Isin(?t?60?)
5 解:C相断线后,ib??ia
设 ia?2Isin?t 则 ib??2Isin?t
s fa?Fm1sin?tco????120?) fb??Fm1sin?tcos(f合?fa?fb?Fm1(sin?tcos??sin?tcos(??120?)?Fm1sin?t?2[?sin60?sin(??60?)]??3Fm1sin?tsin(??60)?3Fm1sin?tcos(??30?)?
合成磁动势为脉动磁动势。
习题十五 1√ 解:(1)解析法 1)令 F?m1?0.9IW1kW1 p1F?m1[sin(?t??)?sin(?t??)] 21fB1?F?m1sin(?t?120?)cos(??120?)?F?m1[sin(?t???240?)?sin(?t??)]
21fC1?F?m1sin(?t?240?)cos(??240?)?F?m1[sin(?t???120?)?sin(?t??)]
2fA1?F?m1sin?tcos??f1?fA1?fB1?fC1?3F?m1sin(?t??)?F1sin(?t??) 2 ——圆形旋转磁势 ?当iA?10A,?t?时, 2f1?F1sin(90???)?F1cos?
2)当iA?5A,?t?5??150?时 6f1?F1sin(150???)?F1cos(60???) f3F?m12+A
iA?5A?90000600900?iA?10A
(2)由于三相绕组对称,通入的三相电流也对称,所以三相基波合成磁势为圆形旋转磁势,并且在空间按余弦规律分布。又由于当某相电流最大时,基波合成磁势的幅值位于该相绕组的轴线上。圆形旋转磁势的旋转角速度=电流的角频率。 1)iA?10A,?t?如上图所示。
?2?90?时,A相电流最大,所以F1位于+A轴上,
5??150?时,时间变化了150??90??60?,所6?以F1从+A轴沿正向转过了60。如上图所示。
2)当iA?5A,?t?2√ 解:
p=2 p=1
3√ 解:1)每个线圈的磁势Fc?WcIf?10?150?1500安匝/极
2)每极磁动势幅值 Fm?5?Fc?5?150?0
75安匝00极 /单层同心式绕组可看成另一种接法的单层整距绕组
Z201???10,由题知:?1?13 q?32pm2?11?10?13q?13sinsin12?2 kq1? ??0.791?111.26413qsin210?sin32 kW1?kq1?0.791 (单层同心式绕组可看成单层整距绕组)
1?10?3?13q??13sinsinsin200?22????0.1 kW3?kq3?????110sin201qsin3?132310?sin244基波 Fm1?FmkW1??7500?0.791?7553安匝/极
??三次谐波 Fm3?
4141?FmkW3???7500?(?0.1)??318.5安匝/极 ?3?3
1?10?13q?13sinsin12?2 kq1? ??0.791?111.26413qsin210?sin32 kW1?kq1?0.791 (单层同心式绕组可看成单层整距绕组)
1?10?3?13q??13sinsinsin200?22????0.1 kW3?kq3?????110sin201qsin3?132310?sin244基波 Fm1?FmkW1??7500?0.791?7553安匝/极
??三次谐波 Fm3?
4141?FmkW3???7500?(?0.1)??318.5安匝/极 ?3?3