trac ngiem an toan dien

trac ngiem an toan dien

TRIJdNG DHSPKT TPHCM E E T H I 0 I ( 0 7 tr a n g )

Dirng cho ciic l6p:081022A

Thdi gian: 60 phrit(SV kh6ng iltloc sir dung tdi li6u)

4 Di€n trd cria cd thd ngddi 6nh hrrdng nhu thd nio ddi vdi mfic d6 tiic hai cfia ddng ili6nqua ngddi?

a DiQn tr& ngutdi ldn, mtc dQ tdc lmi tdng b DiQn trd ngadi nh6, mtc dQ tdc hqi gidm

c EiQn tr& ngtdi nh6, mftc dQ tdc hai tdng d Kh6ng xdc dinh dtqc '

5 Ddng di€n qua ngudi khi ngrrdi cham vdo I ctrc cia m4ng di6n 3 pha di6n r{p d6y U,tAn sd f, diQn trd c6ch di6n cfra dAy din so vdi da't R., di6n dung C vd cti6n trd Rnn ilddcxdc clinh bhng bidu thfc sau:

c Tudng, nAn bi rd diQn

2 DiQn 6p btrdc xut't hi6n khi ndo:

a Ddy ddn bi hu cdch di€n

c Ddy ddn diQn bi dtr t,d rrti xu6'ng ddt

3 Gi6 tri di6n tr6 hic binh thrrdng ld bao nhi6u?

b U.pac= 50V, U,.prc= I00V

d Urp,qc= 60V, U,.pDC= I00V

b Ltip d(r cdc thiA't bi chi€'u sdng

d Bi phdng di€n b&i di€n dp cao

a Cham tr(c tidp vito y\t rnang diAn

c Rd ri di€n & cdc dung cu cdm tay

7 Nguydn nhdn ndo kh6ng phii ld nguy6n nhAn dAn ddn tai nan ddi vdi di6n dp th6'p:

8 d ngay ch6 cham dt't, diQn trd cfra di't se do ddng chay qua diOn tich nh6 Cing

xa vi tri ndy, di6n trd cfra dA't sE theo khodng ci{ch, sd sut 6p di6n thd s6 nh6.

b 2 m

d 4 m

b AC: l5mA vd DC: 45mA

d AC: 20mA vd DC: 45mA

17 EiQn 6p tidp xric md ngddi se chiu ri{c dung khi o ngodi 20m ld:

a AC: I)mA vd DC: 50mA

c AC: 20mA vd DC: 50ntA

14 COng tdc vdi thidt bi di6n cao 6p kh6ng c6t rti6n ld:

a' Nhftng vi€c ldm bAn ngoai rdo chiin cila thidt bi dang mang cliQn hoQc ngodi khoringcdch an todn vdi thiAi bi dang mang diAn

b Nhrtng vi€c ldm tran cac thiA? bi dqng kin dang ltoat dilng nhu do d0 rung dQng co cli€ncao dp

c' Nhilng vi€c ldm 0 gdn hodc ffan cdc bQ phdn vd rhi\'r bi tlang mang diQn kh6ng c6 khdndng che chiin, c6 khd ndng gdy nguy hidm cho ngudi ldm t,iac

16 Gi6 tri ddng rli6n ldn nh6't kh6ng nguy hidm ddn ngudi li:

l8' Trong hC thdng di6n nio sau ddy: khi hu h6ng crlch di6n, ddng su cd g6y sut iip ngudn, nhi6u di6n tr) ldn vd cd khi ndng g6y ch6y cao.

19 Dd lo4i tril hiQu frng mdn che trong ndi da't tQp trung, khodng c6ch gifa c6c cocthrrdng bhng mdy ldn chidu clhi coc (hiQu fng ldm gi6m khi nang tdn ddng cham ddt cfiamdt coc vio virng rlt't lAn c{n):

20 Nguy6n nhAn kh6ng ph6i ld nguy6n nh6n dAn ddn tai nan cldi vdi mang di6n 5p cao:

21 Khoingcdch an todn phu thu6c vdo:

22.C6 ttrd Uidu di6n strphAn bddiOn thdchung quanh ch6 cham dA't qua vat ndi ddt hinhb6n cdu theo cdng thffc nho sau dAy:

24.86o v€ ndi d6't clugc rip dung vdi:

25.Tdc dung cria ddng di6n Adi vCi cd thd con ngddi phq thuQc nhidu ydu td Kh6i niQmndo ld kh6ng thing?

a Thdi gian tdc dung cdng lAu cdng nguy hidm

b Di€n tr& crta ngtdi gidru ti l€ t,6i thdi gian tdc dung cfia ddng diAn

c Tdn sd ddng diQn cdng cao c'dng ngur hidm

d Ddng di€n bd c6 thd BAt,chAi ngildi

26 Pham vi sfi dung hO thdng ndl ddt TT ld:

c Mang diQn c6 khd ndng mt| r6ng cdi rqo d Tdt cd diu ding

27.Kh1c6 hi€n tdQng cham clat, ngudi g{p nguy hidm khi:

a Khodng cdch so didm chatn tlA'r ngoai 20nt

b Dtng rd1 gdn didm clrum dti't

c Dttng cdch didm cham ddlt vd khodng cdch girta hai chdn rd't nhd

d Dirng tAn vbng trdn ddng ilft'

28 Tim ph6t biOu sai, trong m?ng TN, dC gi6m trl sO Aien rip ti6p xfc ta c6 th6 thgc hiQntheo c6c ciich sau dAy:

a Gidm tidt di€n ddy trung ttuh

b N6i v6 thi€t bi tdi mQt hQ ttuing nai dat ph1r

c Vila bao t,€ ti€p dAt cho thiAt bi t,*a bao vQ ily trung tinh

d Co a vd b diu drtng

2 9 K h i b f c h a m v 6 , d i 6 n 6 p t i d p x f c s € b l n g 0 k h i :

30 D4c didm cfia h€ thdng ndi Odt nio sau ddy th6a cdc ydu td: Thidt kd vh vAn h)nh phfic tap, srJ b6o drldng crich diQn cdn phii c6 chuy6n m6n; Su md r6ng ludi g4p kh6 khdn; C6 d0 tin c{y cung cdp di6n cao; Ddi h6i b6o vO qu6 6p m6t c6ch nghi6m ngat.

31 MQt ngddi cham truc tidp vdo mdt cdc cfra mAng diQn TT Ddng tliQn chay qua nguldi

ld bao nhi€u khi tti6n iip ngu6n 380/220V, Rng- 1000fJ?

32 MQt ngddi cham tnJc tidp vdo mdt pha cria m4ng diQn TN Ddng diQn ch4y qua ngddi

ld bao nhi6u khi di€n rip ngu6n 3801220Y, Rng- 1000eJ?

b 380ntA

d l27mA

crrc cfra mqng di6n I pha, phadi6n rip tJ=220Y, Rne = 2kf),ngddi c5 gi6 tri lh bao nhi6u:

b 73 mA

d KAl qud khdc

33 MQt ngUdi cham gi6n tidp vdo mang diQn IT, diQn

r{p tidp xfic d4t l6n ngrrdi bhng bao nhi€u khi khi tliQn

34 Khi ngudi cham vdo I

cdn lai bi ch4m ildt gidt

Rncn= l0ko Ddng diQn qua

35 Ddng diQn qua ngUdi khi ngudi cham vdo I ctlc

ctia mang dien 3 pha diQn,{p U - 3801220 V, tAn sd

f = 50 Hz, di6n trd cdch di6n cira dAy dAn so vdi dA't

36 Trong ludi diQn dd hoc, cham vio lrrdi cli€n nio nguy hidm nhdt:

a Cham vdo I cuc cila lttdi I pha c6 trung tfuh cdch ly

b Chqm vdo I ctc, m|t dAy b1 clmm ctia ltdi I pha cd trung tinh cdclt Ly

c Cham vdo 2 ctc crta Mdi I pha c6 trung tinh cdch ly

d Chqm vdo I cttc cila ludi I pha cd trung tlnh n6'i ddt

37 Muc dich cria vi6c ndi dat lAp lai dAy trung tinh ld:

a BdovQ mdt pha b Bdo v€ ngdn mach pha

38 LJu didm ldn nht't cria sd dd TNS so vdi c6c sd dd ndi da't nrac ta:

39 Ndi dt't v6 thidt bi ld ndi d{t an todn vi:

a Ldm gidm nhd nhdt ddng diQn qua ngtdi khi ngtdi cham vdo thidt bi cham vd

b Ldm gidm nhd nhdt ddng di€n cham v6

c Ldm gidm nh6 nhdi ddng diln cham tldt

d Ldm tdng diAn ff& cdch diAn crta thiAi bi

40 Vdi thidt bi c6 diQn 5p < 1000 V, qury dinh cliOn trd ndi ddt le:

41 Vdi m?ng diQn 3 pha 380/ 220V c6 trung tinh ndi d6't:

a Khbng cdn bdo vQ ndi ddy rrung tinh

b Chi cdn thuc hi€n bdo t,A n6'i ddy trung tinh ndu tdi cd c1ng sudi ldn

c Thqc hi€n bdo vQ ndi ddy tlnh tqi nhrtng nrti ddc biAt nguy hidm vd mQt an todn

d Tdt cd d0u sai

4 2 T r o n g h Q th d n g c l i O n n d o s a u d A y : k h i x i y r a h u r h 6 n g c d c h d i Q n , d b n g s r , r c d t h r l n h t ' tthddng th6'p vd kh6ng g6y ra nguy hidm, vd khi sy cd thff hai x6,y ra trdn pha khi{c, n6 sOtao n6n dbng ng6n mach v) gdy nguy hidm

43 Vai trd cfra thidt bi d6ng cdt lh:

44.D6i vdi CB ha 6p c6ng nghiQp lo4i MCCB, ngddng ti{c dQng ti6u chudn cfra bQ phdnril:

a 1 , , = ( 5 + 1 0 ) I , b 1 , , = ( 7 + 1 4 ) I ,

4 5 D A m b 6 o b 6 o v O c 6 c h o n lo c l h :

a Ndu CB nhdnh kh1ng rdc d1ng tli CR nhdnh chinh tdc d6ng

b Qud tdi & nhdnh phqt thi CIJ nhdnh plru plfii tdc d6ng

c Ngdn mach & nhdnh ndo tlti chi CB nlfinh d6 tdc dQng

d CB nhdnlt chtnh vd CII nhdnh plru cung tdc dQng

4 6 D d n g I , , l i :

47 Chi sd P la:

a Qui dinh mtc chdng xAm nhLp cfia vAt thd riin t'u ntoc

b Qui dlnh mftc an rodn ch6'ng nd

c Qui dinh mtc an todn cl6ng chdy

d Tdt cd cdc cdu tAn dAu dilng

48 C6c thidt bi RCD vd RCCB cdn sfr dung gh6p vdi mr{y c6t ha 6p hay cAu chi ddb6o vd chdng qud ddng vi chdng ng{n rnach:

49.Ddi vdi b6o vQ chdng cham cliQn gi6n tidp trong hQ thdng c6 ndi dd't kidu TT, gi6 tri thdi gian cdt cdc dai rlng v6i I ^, kh6ng dr/dc vt/dt quii:

b Khing cri khd ndng bdo v€ diAn gigt

d Nguy co hoa hoan cao

b Gidm diQn dp ri|fu xtic

d Gidm diQn dp budc

rb d phia tai, (2) Ddng tric clQng clinh mfc crla thidt bi chdng ddng rd d4t d phia ngu6n phii ddng ttinh mfc cfia thidt bi chdng ddng rd dflt d phia tii:

53 Trong m?ng 3 pha c6 trung tinh ndi Aa't, Oidm ndo kh6ng lh r-ru ti€n cfia mang:

a Khi xdy ra ngiin mach I plru cham ddi, tdc dQng ciit ngu6n vdi thdi g,ian ngdn

b Ddm bdo tinh hAn nc cung cA'p diAn

c Gidm bdt su nguy hidm do clnm dd't gdy n€n

2 r ^ \

d I a I c a a e u s a l

54 Mang diQn duqc rhrlc hi6n b6o v€ ndi aay trung tinh khi t[ng sd ndi d6't lap l4i thi:

a Tdng diQn dp budc

c.Tdng diQn dp tidp xilc

55 EiQn trd cfra hQ thdng ndi dA't phu thuQc

a ChiAu ddi coc ndi ddt

c Ei€n tro sudt cia dat

56 MQt ngudi cham tr{c tidp vdo hai ctlc cfia m4ng

di6n TT Ddng cli6n chay qua ngddi li bao nhi€u khi

c 380 V

58 Cho m4ng diQn

d K€t qua khdc

Cho U,6 virri cham = I 1(V), diQn trd ngucri Rne = 1 (KQ)' Rn =0,

Rno = 4(Q) Ddng diQn qua nguoi ld:

a Ing = 10,95 mA

b Inx = 1095 mA

c Irt< = 10A

d Ins = 20A

59 Ngucri dimg cr{ch ch6 ch4m dAt x = I l00cm, ddng diQn

cham d6t tu = 10004, diQn tro su6t cira d6t p6 = 100 Q.m, bucvc

chdn a = 0.8m DiQn 6p budc li:

a U6 = 1.05 V

c U6 = 25.4 V

60 Dbng <liQn qua ngudi khi ngrfdi cham vio I cr"fc

cfia mang diQn 3 pha tli6n 6p ddy U = 400V, tAn sd

f = 50H2, cliQn trd crlch rliQn cria ddy d6n so vdi

tldt R.= 66.3 MQ, di6n dung C=10FF vd diQn tr6

Rne=lKQ c6 gi6 tri li bao nhi€u:

Dilng cho c6c l6P 081022A Thdi gian: 60 Phft (SV kh6ng drrgc sfi dung tii liQu)

1 Tidp xric trt/c tidp ln tidp xf c vdi:

a V6 dQng co bi rb di€n b Ddy ddn di€n kh1ng bQc cdch di€n

c Trtdng, nin bi rd diQn d' Cd 3 cAu rAn

2 Ngodi tdc h4i <ldn hQ thAn kinh vi thinh gi6c, ngddi ldm viQc 6 m6i trddng c6 tidng 6n

vd rung dQng vddt qu6 quy clinh cdn bi t6c h4i ndo?

3 Gi6 tri di6n trd khi mdt ldp sifng li bao nhi6u?

a it nguy hidm hon

c C6 gid tr! nhu nhau

a Tay- thAn- tuY

c Tay phdi- thdn- chdn

a Ua = K/x

c U a = x / K

8 Ngudi cing dfng xa vi tri tidP ddt

ldn T4i virng diQn thd kh6ng thi:

b 80 - 1.000 0

d 10.000 -100.000 o ddng xoay chidu c6 tdn sd c6ng nghiOp

b Nguy hidm hon

6 Tai nan lao dQng x6y ra do thidu rdo chdn, thidu bao che thuoc nguyen nh6n nio?

a Nguy|n nhan ki thuQt b' NguyAn nhAn td chtrc

c Nguy€nnhdnv€ sinh d' Nguy€nnhdn khdc

i C6tnd Uidu di6n su phdn bd diQn thd chung quanh ch5 cham ddt qua vat ndi ddt hinh b6n cdu theo c6ng thfc nho sau ildY:

9 DiQn 6p tidp xric md ngddi sO chiu t6c dung khi o ngodi 20m ld:

b U u = R , t ' l , t

d' U,, =U,

10 C6c thinh phdn diQn trd cira bQ phQn ndi ddt E9 g<\

Cdn b0 coi thi khong Siai thich gi thAn

a DiQn tr& tdn crta ctc n6'i dd'r (kd cd diQn tr7 fia'p xric).

b Di€n tr6 thudn cfia bdn than cuc n6'i dd'r vd ddy ndi ddt.

c EiQn tr& thudn crta bdn thAn ctc n6'i ddi.

d Cd avd b d)u dilng.

11 Theo dudng cong an todn (d4c ruydn thdi gian- diQn dp), vdi criQn d,p c6 gid tri u, = 50V, thdi gian cho ph6p ddng qua ngddi ld:

15 Di6n 6p budc xud't hiQn khi ndo:

a Ddy ddn bi hu cdch cti€n b V6 dQng co bi cham pha

c Ddy ddn di€n bi drrt t,d roi xu6'ng crdt d Tudng bi nhi6m cti€n

16 d ngay ch6 cham dA't, cliOn trd cfia dd.t se do ddng chay qua diQn tich nh6. cing xa vi tri ndy, di€n trd cfia da't s€ theo kho6n g cl,ch,sd sut rip ctiQn thd s€ nh6.

a V6 han

c I}s

12 Nguydn nhdn kh6ng ph6i ln

a Vi pham khodng cdch an rodn

c Cdc ddy ddn boc cdch dien bi hu h6rtg

13 Nguydn nhdn d6n ddn ho6 hoan vi chiiy

a 16 ) I,o

c ChQp di€n & m6i rrrdng hori cttd't d6 chdt, nd

14 Tidp xfc gidn tidp li tidp xfc vdi:

b Ddng crit cdc thi|i bi cao dp

d Sft d4ng diQn kh6ng dung qui cdch

nd vd dicn:

b Ngiin mach

cl Cd 3 cdu d)u dilng

b DAy ddn diQn kh6ng boc cdch di€n

d COng tiic bi ht cdch dien

b nhd vd tdn7

d ldn vd tdng

b 8 m - I ) n t

d 6 m - 8m

b DiQn tich yd cip sud't ilA'p xtic

d Cd 3 cdu diu dilng

1 7 ' N g u y d n n h d n n i o k h 6 n g p h i i l d nguyOn n h a n d A n d d n ta i nan doi vdi di6n 6p th6.p:

a Clnm trLtc tidp vdo t'Qt rnung crian b Liip ddt cdc rhi\i bi chi€'u sang

c Rd ri di€n & cdc dung cu cdm my d Bi ph6ng criQn b&i di€n dp cao

18' Khoing cr{ch nh6 nh6't theo quy ttinh cAm nguoi dOn gAn thict bi di6n ngoai troi khi xdy

b Cdch di€n ctia mang diQn

(

20 Di€n trd crja ngddi phu thu6c vio ctic ydu td nio?

21 Ei€n 5p budc kh6ng phu thuQc vdo ydu td nio?

a Khodng cdch budc chdn ngtdi 6 Ddng cliOn cha1, trong dd.t

c Khodng cdch til chdn ngudi ddn didnt cham ddt d Tidt di€n ddy ddn

22.DiQn6p brrdc phr; thuQc vio ydu td nio:

a Khodng cdch tit vd thiAl bi r)uqc ndt ddt vit didm ndi ddt b Vbng trbn ddng thA'

d C h i c 6 a v d c

c Mtlc d0 cdn bdng thd

23 DiQn 6p tidp xric ldn nhdt cho ph6p d4t l€n

l d :

ngddi trong didu kiQn kh6 rrlo theo TCVN

24 Dd loai tril hiQu rlng min che trong ndi ddt t6'p trung, khoing c6ch giira c6c

25 Khi c6 hiQn tddng cham clt't, ngudi g4p nguy hidm khi:

a Khodng cdch so didm clmm ddt ngodi20m

b Drtng rdt gdn tlidm cham dA't

; ;:i;, caci adm chqm ddt vd khodng cdch girta hai chan rdt nh6

d Drtng tAn vdng trbn ttdng rhd

26 Khi bi cham v6' tli€n 6p tidp xric sE bhng 0 khi:

a Dirng trAn ghd cdch dtQn

c Etng tr?n sdn kim loai drrQc L , l J U I l S a t c t , r u t ' ndi vdi thidt bi

2,l.Dlcdidm cfia hQ thdng ndi Odt ndo sau dAy th6a c6c ydu td: Sd dd don gi6n' dd ki€ gi6n, d6 ki6m tra, bio dddng, c6 thd md iqng ho4c cii tao; chdng duoc nguy cd h6a hoan'

b 2.s

28 MOt ngddi cham tnJc ddp vho hai ctJc cria mqng di6n TT'

29 MOt ngddi cham gi6n tidp vdo mang di6n TN'

diQn 6p tidp xric dat 16n ngddi bhng bao nhi6u khi

khi diQ,n 6p ngudn 3801220V Rng - 1000Q' Rn= RP=

4f), vcri Rp lddiQn trd n6i d6t cho thii5t bi?

b 2 2 0 m A d.440mA

30 Nguoi dimg cdch ch5 ch4m d6t x = l l00cm, ddng di6n

cham d6t tu = 10004, diQn rro su6t cira d6t p6 = 100 O.rn, UuO.

chdn a = 0.8m DiQn rip buoc li:

a U6 = 1.05 V

b Ub = 98.09 V

c U6 = 25.4 V

d K€t qud khtic

31 Khi ngddi cham vio I cr-/c cria m?ng di6n I pha Bidt di6n 6p

Rndn= l0kQ, Ro = 4f) Bo qua dQ sqt iip do R6, Rp, 21,i1, ,rV-\

Ddng ili6n qua ngddi c6 gi6 tri ld bao nhi6u:

U

trl

r r o

32 Di6n 6p ti€p xfc Utxl vd Utx2 khi ngrrdi cham

gi6n tidp vio mang di€n 3 pha ili6n dp U= 3g0/220V,

di6n trd.Rne=l kO, Rpl=le, Rp2= lge vcyi Rp lidiQn

trd n6i dAt cho thitit bi, cd gi6 tri ld bao nhi6u?

a N6'i ddi ddy trung ttnh

c Ndi dAi he thdng ch6hg sir

b 18 mA

d K?'t qud

b Utxl = 20 V vd Urx2 = 360 V

d Ket qua khdc

33 Trddng hop ndo di6n 6p pha s6 thay ddi ndu l pha cham cla.t:

a Mang 3 pha cd trung tinh ngu6n n6'i ttdt

b Mqng 3 pha c6 trung tinh ngudn hodn todn c(tch ty

c Mang 3 pha c6 trung tfnh ngu6n cdch ly qua m6t tr& khdng 22

d TAi cd d0u sai

34 Trong mang 3 pha c6 trung tinh ndi ddt, didm nio kh6ng l) uu ti€n cria mang:

a Khi xdy ra ngiin mach I pha cham dd't, tdc dQng ciit rgu6n vdi thdi gian ngdn

b Ddm bdo t{nh hln nc cung cd'p di\n

c Gidm bdt su nguy hidnt do cham tl6't gd1,n€n

d Tdt cd d|u sai

35 Khuydt didm ldn nh6't cr.ia sd Od tN ta:

b Kh6ng c6 khd ndng bdo v0 tti€n gidt

d Nguy co hod hoan cao

b N6'i dd't v6 thiei bi

d Tdt cd cdc trtdng hop tAn

37 Trddng hop ndo nguy hidnr hdn khi con ngddi cham vio I pha cia mach 3 pha:

c Cd trung t{nh cdch ly qua c'u6n khdng c6 tinh cdm cao d Tdt cd ddu sai

38' Mang di6n duoc thdc hicn b6o vd ndi day ffung rinh khi tdng sd ndi da't tAp tai thi:

a Tdng diQn dp budc

_ _ _ t l

<-U=220 V, Rnn = lkf),

Cdn bo coi thi kh6ng gidi thich gi th€n

b Gidm diQn dp fiA'p xtic

Page 4

c.Tdng diQn dp tidp xilc d Gidm diQn dp budc

39 DiQn trd cria hQ thdng ndi Adt phu thuQc vdo:

a Chi6u ddi cpc ndi ddt b Khodng cdch giira cdc c7c

c Ei€n tro sudt cila diit d- Tdt cd diu dung

40 DiQn 6p budc U5 ddQc x6c dinh bhng bidu thfic sau:

42 Chfic ndng cfia dao c6ch ly:

43 D6m b6o bio vO c6 chon loc ld:

a Ndu CB nhdnh khbng tdc dQng thi CII nhdnh ch{nh tdc dQng

b Qud tdi & nhdnh phq tli CB nhdnh phry phdi tdc d6ng

c Ngdn mach & nhdnh ndo tlti chi CB nlfinlt do tdc dQng

d CB nhdnh chinhvd CB nhdnh phu cilng tdc dQng

44 Chtc ndng chinh cria RCCB li:

45 Cdu nio sai vdi MCB:

c Ddng ctit ngtin mqch 25 kA +65 kA d 2, 3, 4 c{c

46 Chon ddyl c6p t<dt hgp vdi chon thidt bi b6o v6 nhim muc clich:

a Ddm bdo ddy/ crip kh6ng bi chqm chQp

b Ddm bdo thidt bi bdo t,0 bti6 t,A dtoc dd1'/ cdp khi qud tdi/ ngdn mach

c Ddm bdo thidt bi bdo vA hout d)ng chinh xdc

d Tdt cd cdc cdu tAn dAu dting

47 Chtc ndng chinh cira rndy bidn ddng ld:

a Cdch ly so cdp vd tltt cdp

b BiA'n ddi aang diQn so cA'p thdnh ddng diQn c6 gid tri 5 A

c Bdo vA chdng ngiin mach

d, BdovQ chdng qud tdi

48 Vdi 1&, le ddng rd ti{c cl6ng lim vi€c thi th6ng sd quan trong nhd't cira thidt bi chdngddng rd RCD le ddng rd kh6ng t6c dQng 1^ thidt bi RCD kh6ng tdc d6ng ndu:

50' Trong thuc td do diQn trd ngddi thay ddi rrong pham vi r6't r6ng, vi vay dd an todn cho ngtrdi trong moi trddng hop, dien 6p tidp xric U1 cdn cd gi6 tri:

a I o 1 0 5 I ^ ,

c I o : 0 5 I^,

49.DiQn r{p tidp xric mi ngr/di

a U,, -Ud -U, = 0

c U o = U ,

a < 25V

c < l 2 V

a AC: I)mA vd DC: 50ntA

c AC: 20mA vd DC: 50ntA

b Mach 3 pha c6 trung tinh cdch ty

d Tdi cd diu sai

b AC: I5rnA t,d DC; 45rnA

d AC: 20mA t,d DC: 45mA

b Cdch di€n cila mang diAn

52' Nguyen nhdn kh6ng phii ld nguycn nh6n d6n ddn tai nan ddi vdi mang di€n iip cao:

a Vi pham khodng cdch an todn b D6ng ciit cdc thiA.t bi cao ap

c Cdc ddy ddn boc cdch diQn bi hu lt6ng d st)r dung diQn kh6ng dung qui cdch

53 86o vQ ndi d6't duoc rip dung vdi:

a Mach 3 pha cd trung tinh n6'i dd't

c.Cdc mqng cdp ngdm quun trl)ng

54 Gi6' tri ddng didn ldn nhait kh6ng nguy hidm ddn ngudi rd:

55' Tr{c dung cria ddng di6n ddi vdi cd thd con ngLrdi phu rhu6c nhi6u ydu t6 Khrli ni6mnio li kh6ng rtring?

a Thdi gian tdc dungcdng ldu cdng nguy ltidm

b Di€n tr& cila ngildi gidm t! rQ vdi thdi gian rdc dung crta ddng cliQn

c Tdn sd ddng di€n cdng cao cdng nguy hidm

d Ddng diQn bd c6 thd gAt,ch\'r ngtdi

56' Di6n trd cfia cd thd ngrrdi inh hrrdng nhu thd nio ddi vdi mrlc d6 t6c hai cria ddngdi6n qua ngridi?

a' Di€n tr& ngtdi ldn, mtc' dQ tric hai tting b DiQn tr& ngurdi nh6, mtc d6 tdc hati gidm

c DiQn trd ngudi nh6, mt?c' d6 rd rni tdng d Kh6ng xdc dinh dtoc

57 Khodng cdch an todn phu rhu6c vdo:

58' M6t ngudi cham trdc tidp vdo hai ct/c cfra m?ng di6n TT Ddng cli6n chay qua ngddi

li bao nhi6u khi di€n i{p ngudn 390/220V, Rng- 1000e?

Cdn bo coi thi khong gidi thich gi th€n

Page 6

59 MOt ngudi ch4m gidn tidp vio mang cliQn TT,

diQn 6p tidp xric tlat l€n ngddi bXng bao nhi6u khi

tliQn 6p ngu6n 3801220Y, Rng=lQggf), R6=Rn= {Q

voi Rp lhdiQn trd n6i d6t cho thi6t b!?

b 2 2 0 v

d K€t qua khdc

60 MOt ngtrdi cham gi6n tidp vdo mang <liQn IT, iliQn

6p tidp xric d4t l6n ngddi bXng bao nhi€u khi diQn 6p