Third Lesson Induction Motor
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CLIL experience Content and Language Integrated Learning 3 rd Third lesson
description
Transcript of Third Lesson Induction Motor
CLIL experienceContent and Language Integrated Learning
CLIL experienceContent and Language Integrated Learning
3rd Third lesson
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• The induction motor consists of a stator and rotor. The stator is connected to the three phase supply & produces a rotating magnetic field. So an induction motor is like a transformer with stator forming primary winding and rotor forming the secondary winding with the small air gap in the magnetic circuit.
• Upon increasing voltage at no load, reactive current drawn by induction motor will increase, therefore power factor of induction motor decreases but total current drawn will increase upon the increased voltage at no load.
• Here power is measured by two wattmeter method. The advantage of using two wattmeter method is, we can also measure power factor along with power consumed. When power factor is equal to 0.5 one wattmeter will show 00 Watt but the second will give some reading.
• The induction motor consists of a stator and rotor. The stator is connected to the three phase supply & produces a rotating magnetic field. So an induction motor is like a transformer with stator forming primary winding and rotor forming the secondary winding with the small air gap in the magnetic circuit.
• Upon increasing voltage at no load, reactive current drawn by induction motor will increase, therefore power factor of induction motor decreases but total current drawn will increase upon the increased voltage at no load.
• Here power is measured by two wattmeter method. The advantage of using two wattmeter method is, we can also measure power factor along with power consumed. When power factor is equal to 0.5 one wattmeter will show 00 Watt but the second will give some reading.
Three-phase induction motorOBJECT: To study the effect of applied voltage on power factor & current drawn by 3-Фinduction motor
OBJECT: To study the effect of applied voltage on power factor & current drawn by 3-Фinduction motor
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Three-phase induction motor
• For the performance analysis of induction motor, we need to have motor parameters. In those cases where motor parameters are not readily available from the manufacture, they can be approximated from different tests. One of them is no load test.
• Purpose of this test is to find out no load losses i.e core (magnetizing reactance) and mechanical losses for at this condition power consumed is basically because of these losses.
• Balanced three phase voltages are applied to the stator terminals at the rated frequency with the rotor uncoupled from any mechanical load. Speed, current, voltage and power are measured at the motor input.
• For the performance analysis of induction motor, we need to have motor parameters. In those cases where motor parameters are not readily available from the manufacture, they can be approximated from different tests. One of them is no load test.
• Purpose of this test is to find out no load losses i.e core (magnetizing reactance) and mechanical losses for at this condition power consumed is basically because of these losses.
• Balanced three phase voltages are applied to the stator terminals at the rated frequency with the rotor uncoupled from any mechanical load. Speed, current, voltage and power are measured at the motor input.
OBJECT: To carry out no load test of 3-phase induction motorOBJECT: To carry out no load test of 3-phase induction motor
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Three-phase induction motor
CIRCUIT DIAGRAMCIRCUIT DIAGRAM
APPARATUS
1. Voltmeter2. Ammeter3. Two wattmeters
4. Auto transformer5. speed-meter (tachometer)
OBJECT: To carry out no load test of 3-phase induction motorOBJECT: To carry out no load test of 3-phase induction motor
Induction motor
AIMS
•no load lossesmechanical lossesIron lossesmagnetizing reactance
•no load current•factor power
AIMS
•no load lossesmechanical lossesIron lossesmagnetizing reactance
•no load current•factor power
rpm
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Procedure
• Choose the apparatus and measuring instruments.
• Choose the connection: star or delta
• Make the circuit as shown in figure.
• Disconnect the load connected.
• Start the motor without load at the 10% plus of the rated voltage and frequency.
• Note down the readings of all instruments connected.
• Repeat the test with decreasing voltages until the motor speed decreases significatly.
• Choose the apparatus and measuring instruments.
• Choose the connection: star or delta
• Make the circuit as shown in figure.
• Disconnect the load connected.
• Start the motor without load at the 10% plus of the rated voltage and frequency.
• Note down the readings of all instruments connected.
• Repeat the test with decreasing voltages until the motor speed decreases significatly.
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Observation - ResultsObservation - Results
n. V I0 Wa Wb speed P0 Q0 cosf 0
Pc=
Rph*I2PI&S+
PF&Wo V
[V] [A] [watt] [watt] [rpm] [watt] [var] [watt] [watt]
1
2
3
4
5
6
7
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ELABORATIONSREADINGS
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ELABORATIONSELABORATIONS
WbWaP 0WbWaP 0
WbWaQ 30 WbWaQ 30
0
00 coscos
P
Qarctg
0
00 coscos
P
Qarctg
203 IRP phasecopper 203 IRP phasecopper
WFSIIRP ph &&3 200 WFSIIRP ph &&3 200
lossesmeccanical
lossesWindageFrictionWF
lossesStrayIronSI
lossesCopperIRph
_
___&&
___&&
_3 20
lossesmeccanical
lossesWindageFrictionWF
lossesStrayIronSI
lossesCopperIRph
_
___&&
___&&
_3 20
WFIRPSI ph &3& 200 WFIRPSI ph &3& 200
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RESULTSRESULTS
• Diagram
Fig. 2: No-load losses separation diagram.
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Separation lossSeparation loss
W0 = losses at no-load
WF&W = friction and windage losses
WI = iron losses
WC = 3RI2 = stator winding losses
W0 = losses at no-load
WF&W = friction and windage losses
WI = iron losses
WC = 3RI2 = stator winding losses
ciWF WWWW &0 ciWF WWWW &0
c
i
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Observation - ResultsObservation - Results
n. V I0 Wa Wb speed P0 Q0 cosf 0
Pc=
3Rph*I2PI&S+
PF&Wo PI&S V
[V] [A] [watt] [watt] [rpm] [watt] [var] [watt] [watt] [watt]
1 90 1,29 112,5 57,5 2915 170,0 95,3 0,87 7,1 162,9 17,0 8100
2 100 1,33 125,0 47,5 2933 172,5 134,2 0,79 7,5 165,0 19,1 10000
3 120 1,38 145,0 37,5 2955 182,5 186,2 0,70 8,1 174,4 28,5 14400
4 140 1,42 167,5 27,5 2967 195,0 242,5 0,63 8,6 186,4 40,5 19600
5 160 1,60 192,5 17,5 2975 210,0 303,1 0,57 10,9 199,1 53,2 25600
6 180 1,80 232,5 -7,5 2980 225,0 415,7 0,48 13,8 211,2 65,3 32400
7 200 2,10 320,0 -67,5 2983 252,5 671,2 0,35 18,8 233,7 87,8 40000
8 220 2,90 420,0 -130,0 2985 290,0 952,6 0,29 35,8 254,2 108,3 48400
9 240 4,25 620,0 -252,5 2987 367,5 1511,2 0,24 76,9 290,6 144,7 57600
ELABORATIONSREADINGS
n. V I0 Wa Wb speed P0 Q0 cosf 0
Pc=
3Rph*I2PI&S+
PF&Wo PI&S V
[V] [A] [watt] [watt] [rpm] [watt] [var] [watt] [watt] [watt]
1 90 1,29 112,5 57,5 2915 170,0 95,3 0,87 7,1 162,9 17,0 8100
2 100 1,33 125,0 47,5 2933 172,5 134,2 0,79 7,5 165,0 19,1 10000
3 120 1,38 145,0 37,5 2955 182,5 186,2 0,70 8,1 174,4 28,5 14400
4 140 1,42 167,5 27,5 2967 195,0 242,5 0,63 8,6 186,4 40,5 19600
5 160 1,60 192,5 17,5 2975 210,0 303,1 0,57 10,9 199,1 53,2 25600
6 180 1,80 232,5 -7,5 2980 225,0 415,7 0,48 13,8 211,2 65,3 32400
7 200 2,10 320,0 -67,5 2983 252,5 671,2 0,35 18,8 233,7 87,8 40000
8 220 2,90 420,0 -130,0 2985 290,0 952,6 0,29 35,8 254,2 108,3 48400
9 240 4,25 620,0 -252,5 2987 367,5 1511,2 0,24 76,9 290,6 144,7 57600
ELABORATIONSREADINGS
Rph= 1,42 Ω PAV(F&W)= 145,9 W
(P8-PAV)/(P1-PAV)=V8/V1= V8/V1= 5,9753 PI&S= P0-PC-PAV= 108,3 W
Rph= 1,42 Ω PAV(F&W)= 145,9 W
(P8-PAV)/(P1-PAV)=V8/V1= V8/V1= 5,9753 PI&S= P0-PC-PAV= 108,3 W
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Power FactorPower Factor
Cosf 0
0,000,100,200,300,400,500,600,700,800,901,00
0 25 50 75 100 125 150 175 200 225 250
cosf0
0,29:220
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Separation lossSeparation loss
0255075
100125150175200225250275300325350375400
0 20 40 60 80 100 120 140 160 180 200220 240 260
P0 [watt] PI&S+PF&Wo [watt]
PC
PI&S
PF&Wo
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Separation lossSeparation loss
0255075
100125150175200225250275300325350375400
0,0 10,0 20,0 30,0 40,0 50,0 60,0
P0 [watt] PI&S+PF&Wo [watt]
V2 (103)
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Answer to the following questionsAnswer to the following questions
1. How will the power factor vary if the voltage supply decreases?
2. Why is the power measured by two wattmeter method?
3. Which wattmeter will show 00 Watt?
4. What instrument can the motor speed be measured with?
5. How much is the percentage on the current at no load I0 compared with rated current IN?
6. What is the procedure in order to carry out no load test of 3-phase induction motor?
1. How will the power factor vary if the voltage supply decreases?
2. Why is the power measured by two wattmeter method?
3. Which wattmeter will show 00 Watt?
4. What instrument can the motor speed be measured with?
5. How much is the percentage on the current at no load I0 compared with rated current IN?
6. What is the procedure in order to carry out no load test of 3-phase induction motor?
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Translate the following words:Translate the following words:
1. Stator core losses …………………………
2. Hysteresis and eddy current…………………………
3. Magnetizing reactance …………………………
4. Power factor …………………………
5. Speed-meter …………………………
1. Stator core losses …………………………
2. Hysteresis and eddy current…………………………
3. Magnetizing reactance …………………………
4. Power factor …………………………
5. Speed-meter …………………………
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Fill the gapsFill the gaps
1. An induction motor is like a …………….... with stator forming ……..……. and rotor forming the ……………. winding.
2. When power factor is smaller than 0.5 one wattmeter (Wb) will show …………………………………….
3. Upon increasing voltage at no load, power factor of induction motor ………………………
4. In those cases where ……………………… are not readily available from the manufacture, they can be carried out from different tests. One of them is …………………….
5. Purpose of no load test is to find out ………………….. i.e. core ……………………….and …………………….
1. An induction motor is like a …………….... with stator forming ……..……. and rotor forming the ……………. winding.
2. When power factor is smaller than 0.5 one wattmeter (Wb) will show …………………………………….
3. Upon increasing voltage at no load, power factor of induction motor ………………………
4. In those cases where ……………………… are not readily available from the manufacture, they can be carried out from different tests. One of them is …………………….
5. Purpose of no load test is to find out ………………….. i.e. core ……………………….and …………………….
