in gol si in scurtcircuit
Chestiuni de studiat :
Determinarea experimentala a raportului de transformare;
Determinarea experimentala a rezistentei infasurarii statorului;
Incercarea de mers in gol a motorului asincron trifazat. Determinare experimentala a parametrilor schemei electrice echivalente corespunzatoare ramuriide magnetizare xμ2, Rw. Metoda separarii pierderilor.
Incercarea de scurtcircuit a motorului asincron trifazat. Determinarea experimentala a parametrilor schemei electrice xσπ, Rπ. Determinarea grafica a curentului de pornire.
Predeterminarea caracteristicii mecanice n=f(M) U=U1n=ct
Schema electrica de montaj :
R
RT
S
T
R M
Date nominale :
Y Dnn=910 rpm fn=50 Hz cosφ= U20=17 V I2=21 A |
M 3
Pn=5kW
UnI/UnII=220/380 V
InI/InII=21.6/12.5 A
Tabele de date masurate si calculate :
Determinarea raportului de transformare:
kT= Conexiunea stea : U1f= U2f= |
U1 |
U2 |
U1f |
U2f |
kT |
V |
V |
V |
V |
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kT=
Rezistenta infasurarii statorului
R1f= U1f= |
U2
U1f
U2f
kT
V
V
V
V
R1f=0.88 Ω
Incercarea de mers in gol :
U1f=
I10f=I10=3 A
cosφ=
Iw=I10cosφ10=3*0.288=0.864 A
Iμ=I10sinφ10=3*0.95=2.87 A
Rw=
xμ=
Separarea pierderilor :
P10=PFe1+PJ+PFe2+PJ2+PF1v
f2=sf1
s 0 =>f2 0=>PFe2 0
E2s=E20*s
s 0 =>E2s 0 =>I2 0 =>PJ2 0
R1 xσ1 xσ2 R2
U1f R2 Iμ
R1 xσ1
U1f Rw xμ
U10 |
I10 |
P10 |
U10f |
I10f |
cosφ10 |
Iw |
Iμ |
Rw |
xμ |
P10I |
V |
A |
W |
V |
A |
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A |
A |
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W |
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Incercarea de mers in gol :
U1k |
I1k |
P1k |
U1kf |
I1kf |
cosφ1k |
Rk |
xσk |
R2I |
zk |
V |
A |
W |
V |
A |
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U1kf=U1k=210V
I1kf=
cosφ1k=
Rk=
Zk=
xσk=
R2I=Rk-R1f=1.92-0.88=1.04Ω
Determinarea curentului de pornire Ip
Caracteristica mecanica n=f(M) U1=U1n=ct
f1=f1n=ct
s |
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n |
Rpm |
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M |
N*m |
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n1=910rpm
s=n=n1(1-s)=910(1-0.9)=91
M=
xσ1+xσ2=xσk
Observatii si concluzii :
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