INSTRUCTIOn MANUAL FOR BRUSHLESES. AC GENERATOR MODEL TWYFull description
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Spontaneous induction to the absolute
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Dave Elman Induction
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A useful induction form to use in Early Years settings.Description complète
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Descrição: Dave Elman Induction
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Quick revision for iit jee physics chapters
Mathematical Induction
Induction Quiz2Description complète
Dave Elman Induction
EE303
INDUCTION GENERATOR
Instructed By: Ms. P.M.A.U. Karunapala
Name
: G.R. Raban
Index Number
: 070384P
Field
: EE
Group
:8
Date of Performance
: 17/11/2009
Date of Submission
: 08/12/2009
OBSERVATIONS NAME
: G. R. Raban
INDEX NO.
: 070384P
GROUP
:8
FIELD
: EE
PRACTICAL : Induction Generator DATE OF PERFORMANCE : 17 – 11 – 2009 INSTRUCTED BY
: Ms. P. M. A. U. Karunapala
1)
Self-excited induction generator
a)
No load characteristics for varying capacitances and constant prime mover speed Speed
=
2500 rpm
Residual voltage
=
3.064 V
Capacitance (µF) (µ F)
Voltage (V)
Mag. Current (A)
Frequency (Hz)
71.2
276.4
2.95
40
69.7
273.6
2.90
40
67.7
268.4
2.70
40
65.7
263.6
2.60
40
60.7
246.1
2.30
40
50.7
174.8
1.30
40
b)
No load characteristics for varying prime mover speed and constant capacitance Capacitance
c)
=
60.7 µ F
Voltage (V)
Speed (rpm)
Current (A)
Frequency (Hz)
243
2496
2.25
40
229
2448
2.05
40
212
2402
1.90
39
188
2348
1.65
38
164
2302
1.70
37
Performance of loaded generator with constant speed Speed
=
2500 rpm
Capacitance
=
71.2 µ F
Voltage (V)
Gen. Current (A)
Load Current (A)
Frequency (Hz)
Torque (Nm)
280
3.00
0
40
2.2
269
2.90
0.50
40
3.0
262
2.90
1.00
40
3.8
251
3.00
1.40
40
4.5
238
3.05
1.75
40
4.9
d)
Performance of the loaded generator without speed regulation No load speed
2)
=
2500 rpm
Speed (rpm)
Voltage (V)
Gen. Current (A)
Load Current (A)
Frequency (Hz)
Torque (Nm)
2500
278
3.00
0
40
2.3
2472
264
2.80
0.5
40
3.0
2458
249
2.75
0.9
40
3.6
2448
234
2.70
1.3
39
4.1
2438
217
2.70
1.6
38
4.4
Grid connected induction generator
Current (A)
Voltage (V)
Power (W)
Speed (rpm)
Frequency (Hz)
Torque (Nm)
1.60
222.0
0
3037
49
2.4
1.75
222.3
40
3052
49
2.8
1.85
222.1
80
3063
49
2.8
2.10
222.3
160
3078
49
3.3
2.35
222.2
220
3098
49
3.7
Calculations 1.
Self Excited Induction Generator
Part (a) No load characteristics for varying capacitances and constant prime mover speed
(i)
Plot of Line Voltage Vs Magnetizing Current
Line Voltage Voltage Vs Magnetizing Current 300
280
260
240
220
) V ( e g a t l o 200 V e n i L 180
160
140
120
100 1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
Magnetizing Current (A)
2.4
2.5
2.6
2.7
2.8
2.9
(ii)
Plot of Line Voltage Vs Capacitance
Line Voltage Voltage Vs Capacitance 300
280
260
240
220
) V ( e g a t l o 200 V e n i L 180
160
140
120
100 50.5
52.5
54.5
56.5
58.5
60.5
62.5
Capacitance (μF)
64.5
66.5
68.5
70.5
Using the above graphs, following values can be calculated.
(i)
Capacitance required required to obtain the rated voltage of 240 V at 2500 rpm is; 68 µF
(ii)
Capacitance required to obtain the rated voltage of 240 V at the rated frequency of 50 Hz. Take this capacitance as C 0. Ic
=
Im
=
VCω E ω
Lm
Take, Ic
=
Im
Im
=
VC0ω
By the graph, Im ∴
C0
C0
= = =
2.175 A Im Vω
=
28.85 µF
2.175 240×2 π ×50
F
Part (b) No load characteristics for varying prime mover speed and constant capacitance
(i)
Plot of Voltage Vs Speed
Voltage Vs Speed 260
240
220
200
) V ( e g 180 a t l o V
160
140
120
100 2300
2320
2340
2360
2380
2400
2420
Speed (rpm)
2440
2460
2480
2500
(ii)
Plot of Frequency Vs Speed
Frequency Vs Speed 41
40
39
) z H ( y c n 38 e u q e r F
37
36
35 2300
2320
2340
2360
2380
2400
2420
Speed (rpm)
2440
2460
2480
2500
(iii)
Plot of Magnetizing Current Vs Speed
Magnetizing Current Vs Speed 2.4
2.2
2
) A ( 1.8 t n e r r u C g n i z i t e n g 1.6 a M
1.4
1.2
1 2300
2320
2340
2360
2380
2400
2420
Speed (rpm)
2440
2460
2480
2500
Part (c) Performance of loaded generator with constant speed
(i)
Plot of Voltage Vs Load Current
Voltage Vs Load Current 290
280
270
260
) V ( e g 250 a t l o V
240
230
220
210 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Load Current (A)
1.2
1.3
1.4
1.5
1.6
1.7
1.8
(ii)
Plot of Frequency Vs Load Current
Frequency Vs Load Current 45
40
35
30
) z H ( 25 y c n e u q 20 e r F 15
10
5
0 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Load Current (A)
1.2
1.3
1.4
1.5
1.6
1.7
1.8
(iii)
Plot of Generator Current Vs Load Current
Generator Current Vs Load Current 3.1
3.05
3
) A ( t n e r r u C 2.95 r o t a r e n e G
2.9
2.85
2.8 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Load Current (A)
1.2
1.3
1.4
1.5
1.6
1.7
1.8
Part (d) Performance of the loaded generator without speed regulation
(i)
Plot of Voltage Vs Load Current
Voltage Vs Load Current 300
280
260
240
220
) V ( e g 200 a t l o V 180
160
140
120
100 0
0.2
0.4
0.6
0.8
1
1.2
Load Current (A)
1.4
1.6
1.8
2
(ii)
Plot of Frequency Vs Load Current
Frequency Vs Load Current 41
(c)
40
39
38
) z H ( y c n 37 e u q e r F
(d)
36
35
34
33 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
Load Current (A)
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
Plot of Torque Vs Speed of Prime Mover
Torque Vs Speed 6
5
4
) m N ( e 3 u q r o T
2
1
0 2430
2436
2442
2448
2454
2460
2466
2472
Speed (rpm)
2478
2484
2490
2496
2502
2.
Grid Connected Induction Generator
(i)
Plot of Power Output Vs Speed
Power Output Vs Speed 250
200
150
) W ( t u p t u O r e w o P 100
50
0 3035
3045
3055
3065
Speed (rpm)
3075
3085
3095
(ii)
Plot of Line Current Vs Speed
Line Current Vs Speed 2.6
2.4
2.2
2
) A ( t n e r r 1.8 u C e n i L
1.6
1.4
1.2
1 3035
3045
3055
3065
Speed (rpm)
3075
3085
3095
Calculation of Efficiency and Power Factor
Efficiency
=
Input Power
=
Outp Output ut Powe Powerr Input Input Power Power
τ
Output Power =
×ω
Wattmeter Reading
E.g. By the data obtained from the observations; = 2.8 Nm
ω
Input Power
=
Efficiency
=
τ
∴
= 3052 rpm 2.8 ×
W = 40 W
3052 3052 × 2π
40 894.89
60
W
× 100%
=
894.89 W
=
4.47%
Real Real Power Power
Power Factor
=
Real Power
=
Wattmeter Reading
Apparent Power
=
VI
Appar Apparen entt Powe Powerr
E.g. By the data obtained from the observations; V = 222.3 V
∴
I = 1.75 A
Power Factor
=
W = 40 W 40 222.3 × 1.75
=
0.10
Speed (rpm)
Efficiency (%)
Power Factor
3037
0
0
3052
4.47
0.10
3063
8.91
0.19
3078
15.04
0.34
3098
18.33
0.42
(iii)
Plot of Efficiency Vs Speed
Efficiency Vs Speed 25
20
15
% y c n e i c i f f E 10
5
0 3035
3045
3055
3065
Speed (rpm)
3075
3085
3095
(iv)
Plot of Power Factor Vs Speed Power Factor Vs Speed 0.6
0.5
0.4
r o t c a F 0.3 r e w o P
0.2
0.1
0 3035
3045
3055
3065
Speed (rpm)
3075
3085
3095
Discussion
Reasons for the no-load test to be designed to result in a lower frequency than the rated frequency of 50 Hz; The Induction generator normally runs on negative slip. This is because its rotor runs
faster than the synchronous speed of the equivalent induction motor. During the no-load test, there will be no active power output. The slip of the generator will be zero or a positive value under this condition. Therefore, in order to achieve a positive slip, the no-load test is designed to result in a lower frequency than 50 Hz.
The cause for variations of the voltage and current waveforms of the generator when loading; In the case of an induction motor, the motor speed is decreased when the load is
increased. But in an induction generator, the power output increases as the load l oad increases, which in turn increases the speed. Therefore, as the load on an induction generator changes, the speed of the generator changes with it. it . This causes the current and voltage output to change.
The importance of induction generators in power generation in Sri Lanka Induction generators can be used in wind turbines and micro hydro installations due to
their ability to produce useful power at varying rotor speeds. It is especially useful in wind power generating stations where the speed is always a variable factor. Induction generators are not suitable for high power applications. Induction generators are mechanically and electrically simpler than other generator types. They are also more rugged, requiring no brushes or commutations. Other advantages of the induction generator are; it is cheaper, reliable in service, light weight, does not require routine maintenance. Therefore, induction generators are ideal for use in remotely located mini hydro plants and wind power generation stations. Self Excited Induction Generators (SEIG) are very useful in isolated power generation because it can easily handle dynamic loads.
Discussion about the above plotted graphs;
1. Self Excited Induction Generator
a)
No Load characteristics for varying capacitance and constant prime mover speed.
i. Line Voltage Vs Magnetizing Current Increase in Line Voltage decreases with increasing Magnetizing Current at constant speed according to equation;
Im
=
E ω
Lm
ii. Line Voltage Vs Capacitance Line Voltage increases with the Capacitance. But the curve tends to saturate at higher values of capacitance.
b)
No Load characteristic for varying prime mover speed and constant capacitance.
i. Voltage Vs Speed Voltage increases with the Speed in a nearly linear manner. ii. Frequency Vs Speed Frequency increases increases with the Speed in a nearly linear l inear manner. iii. Magnetizing Current Vs Speed Magnetizing Current also increases with the Speed.
c)
Performance of loaded generator with constant speed.
i. Voltage Vs Load Current The Voltage decreases as the Load Current increases. The curve is nearly linear. ii. Frequency Vs Load Current Frequency remains constant as load current increases. Therefore, it can be concluded that the frequency does not depend on load current at constant speed. iii. Generator Current Vs Load Current Graph does not indicate a clear relationship between these two parameters.
d)
Performance of the loaded generator without speed regulation.
i. Voltage Vs Load Current Voltage decreases with increasing Load Current. The curve is nearly linear. ii. Frequency Vs Load Current Frequency is almost constant for low values of load current, but decreases rapidly for higher values of load current. These characteristics are shown when there is no speed regulation. Torque Vs Speed Torque decreases with increasing speed in a nearly linear manner.
2.
Grid connected Induction Generator
i. Power Output Vs Speed Power Output increases with increasing Speed in a linear manner. ii. Line Current Vs Speed Line Current increases with Speed in a nearly linear manner. iii. Efficiency Vs Speed Efficiency increases with Speed. iv. Power Factor Vs Speed Power factor increases with increasing Speed in a nearly linear manner.
