POTTI SRIRAMULU CHALAVADI MALLIKARJUNA RAO. COLLEGE … · 2018-11-13 · POTTI SRIRAMULU CHALAVADI...
Transcript of POTTI SRIRAMULU CHALAVADI MALLIKARJUNA RAO. COLLEGE … · 2018-11-13 · POTTI SRIRAMULU CHALAVADI...
POTTI SRIRAMULU CHALAVADI MALLIKARJUNA RAO. COLLEGE OF ENGINEERING & TECHNOLOGY
(Affiliated to JNTU, Kakinada & Approved by AICTE New Delhi)
KOTTHA PETA, VIJAYAWADA - 520001.
Department of Electrical and Electronics Engineering
**********************************************************
MANUAL FOR
POWER ELECTRONICS LAB
III B.Tech II Semester (EEE)
2017-2018
Name: ……………………………………………………......
Roll Number: ……………………………………………....
PSCMR college of Engineering and Technology
ELECTRICAL AND ELECTRONICS ENGINEERING 1
Exp.No: Date:
STUDY OF CHARACTERISTICS OF SCR, MOSFET & IGBT
Aim:To study the characteristics of SCR, MOSFET & IGBT.
Apparatus: 1. Characteristics of SCR, MOSFET and IGBT study unit. 2. Ammeters - (0-500) mA, MC-1 No, (0-25) mA, MC-1 No. 3. Voltmeters - (0-50) V, MC-1 No, (0-30) V, MC-1 No
4. CRO 5. Connecting wires
a) Circuit Diagram of SCR:
b) Expected Graph
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Procedure:
1. Connections are made as per the circuit diagram. 2. Now switch ON the main supply and initially keep V1& V2 at minimum and also set
load potentiometer R1 in the minimum position. 3. By adjusting the Potentiometer R2, the gate current is maintained constant. 4. By adjusting R1, the anode voltage VAK and anode current Ia are noted. 5. This procedure is repeated for different gate currents.
6. The noted values are tabulated and graph is drawn between anode current and anode
cathode voltage.
Tabular Form:
Result:
S.NO Ig1= (mA) Ig2= (mA)
VAK(V) IA(mA) VAK(V) IA(mA)
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b) Characteristics of MOSFET
Circuit Diagram:
Expected Graph:
Transfer Characteristics Drain Characteristics
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Procedure:
For Transfer Characteristics:
1. Connections are made as per the circuit diagram.
2. Initially keep V1& V2 are zero.
3. VDS is kept constant say 10V by varying Drain resistance R1.
4. Slowly vary V2 and note down ID and VGS readings for every 0.5V.
5. This procedure is repeated for different drain source voltages VDS.
6. Graph is drawn between ID v/s VGS at different values of drain source voltages VDS.
For Drain Characteristics:
1. Connections are made as per the circuit diagram.
2. VGS is kept constant at a fixed value say 3.5V by varying the Gate supply V2.
3. Slowly vary V1 and note down the values of ID &VDS.
4. This procedure is repeated for different gate source voltages VGS.
5. Graph is drawn between ID& VDS at different values of gate source voltages VGS.
Tabular Form:
For transfer Characteristics:
S.NO VGS1= (Volts) VGS1= (Volts)
VDS(V) ID(mA) VDS(V) ID(mA)
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For Drain Characteristics:
Result:
S.NO VDS= (Volts)
VGS(V) ID(mA)
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C) Characteristics of IGBT Circuit diagram:
Expected Graph:
Transfer Characteristics Collector Characteristics
Procedure:
For Transfer Characteristics:
1. Connections are made as per the circuit diagram.
2. Initially keep V1& V2 are zero.
3. VCE is kept constant say 10V by varying Drain resistance R1.
4. Slowly vary V2 and note down IC and VGE readings for every 0.5V.
5. This procedure is repeated for different collector emitter voltages VCE.
6. Graph is drawn between IE& VGE at different values of collector emitter voltages VCE.
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For Collector Characteristics:
1. Connections are made as per the circuit diagram.
2. VGE is kept constant at a fixed value say 5V by varying the Gate supply V2.
3. Slowly vary V1 and note down the values of IC& VCE.
4. This procedure is repeated for different gate emitter voltages VGE.
5. Graph is drawn between IC& VCE at different values of gate emitter voltages VGE.
Precautions:
1. Check the all components before making connections.
2. Keep all knobs at minimum position before you switch ON the supply.
3. Working conditions of all the equipment’s must be checked properly.
4. Check the fuses and terminals.
Tabular Form: For transfer Characteristics:
S.NO VCE= (Volts)
VGE(V) IC(mA)
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For Collector Characteristics:
Result:
S.NO VGE= (Volts) VGE= (Volts)
VCE(V) IE(mA) VCE(V) IE(mA)
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Exp.No: Date:
GATE FIRING CIRCUITS FOR SCR (R, RC, UJT) Aim:
To trigger an SCR by using R, RC & UJT triggering circuits and observe the output
waveforms for different firing angles.
Apparatus: -
S.No Apparatus Quantity
1 Triggering circuit Kit 1
2 Unearthed C.R.O 1
3 Connecting probes 1
Procedure:
Resistance firing circuit:
(1) Apply 12V of AC input to the anode and cathode of SCR terminals from a step down
transformer. (2) Connect the anode, cathode & gate terminals of SCR to the corresponding A, K, G
terminals in the R – Triggering circuit. (3) Connect the load of 50Ω/2A between the load terminals.
(4) Observe the variations in the voltage across the load for different firing angles (by Varying potentiometer) with the help of CRO, plot waveforms of firing signals & output
voltage for firing angle 450, 90
0.
RC firing circuits:
1. Apply 12V of AC input to the anode and cathode of SCR terminals from a step down
transformer. 2. Connect the anode, cathode & gate terminals of SCR to the corresponding A, K, G
terminals in the R – Triggering circuit. 3. Connect the load of 50Ω/2A between the load terminals.
4. Observe the variations in the voltage across the load for different firing angles (by Varying potentiometer) with the help of CRO, plot waveforms of firing signals & output
voltage for firing angle 450, 180
0.
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UJT firing circuit:
1. Apply 12V of AC input to the anode and cathode of SCR terminals from a step down
transformer. 2. The rectified output is applied to the UJT terminals through the résistance as shown in
the circuit diagram. 3. Connect the cathode & gate terminals of SCR to the corresponding K, G terminals in
the UJT – Triggering circuit. 4. Connect the load of 50Ω/2A between the load terminals.
5. Switch ON the supply for UJT Triggering circuit.
6. Observe the variations in the voltage across the load for different firing angles (by varying potentiometer) with the help of CRO, plot waveforms of firing signals &
output voltage for firing angle 450, 180
0.
Precautions:
(1) Initially the potentiometer should be in minimum resistance position.
(2) Vary the Potentiometer gradually.
(3) Observe the output waveforms carefully on the CRO
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Circuit Diagram:
Circuit Diagram to obtain Resistance Triggering
Model Graphs:
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Circuit Diagram:
Circuit Diagram to obtain RC Triggering
Model Graphs:
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Circuit Diagram:
Circuit Diagram to obtain UJT Triggering
Model Graphs:
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Result:
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Exp.No: Date:
SINGLE PHASE HALF CONTROLLED BRIDGE CONVERTER
Aim:
To Study and observe the working and operation of a 1 half controlled bridge converter
with R and RL loads & to plot the waveforms across the load and SCR for different firing angles.
Apparatus:
S.No. Apparatus Range Type Quantity
1. Single Phase isolation
transformer
230/115-60-30-0-30-
60115V
1 KVA
Shell type 1
2. SCRs 12A /600 V TYN612 2
3. Power Diodes --- --- 2
4. Load Rheostat 145 / 2.8A Wire wound 1
5. Inductive Load (0-25-50-100-
150mH),2A
…. 1
6. Voltmeter 0-30 V MC 1
7. Ammeter 0-2A MC 1
8. 1 half controlled rectifier
bridge firing Kit
…. …. 1
9. Cathode Ray oscilloscope …. …. 1
10. CRO Probe …. ….. 1
11. Connecting wires …. …. Required
No
Procedure:
1. Connections are made as per the circuit diagram.
2. Firing pulses are applied for the respective SCR’s from the firing circuit.
3. The main supply is switched ON and triggering circuit is switched ON.
4. Wave forms across the load are observed in CRO.
5. Values are tabulated for different firing angles.
6. The output wave forms are plotted on the graph sheet.
7. Switch off the supply.
8. Repeat the above procedure for RL Load.
Precautions:
1. Initially, keep MCB in ON position.
2. Don’t use CRO in dual trace mode.
3. Use fixed terminals of load rheostat.
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CIRCUIT DIAGRAM FOR 1-PHASE HALF CONTROLLED BRIDGE RECTIFIER WITH
R LOAD:
CIRCUIT DIAGRAM FOR 1-PHASE HALF CONTROLLED BRIDGE RECTIFIER WITH
R L LOAD:
TRIGGERING CIRCUIT FOR 1-PHASE HALF CONTROLLED BRIDGE RECTIFIER:
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Waveforms for R-Load:
Single phase HCBR circuit and waveforms for RL-Load:
(a) Circuit diagram for 1-phase half controlled bridge rectifier with RL load
(b) Waveforms of RL load
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Expressionsfor Output Voltages:
R-Load:
0( )
1sin 1 cosm
mavg
VV V d
` = 1 cosmV
RL-Load:
0
1sin cos cosm
mavg
VV V d
Tabular Form:
Load Firing angle
(degrees)
Voltage across load, Vdc
(Volts)
Load Current
Idc
Theoretical Practical Theoretical Practical
R- load
RL – load
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Result:
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ELECTRICAL AND ELECTRONICS ENGINEERING 21
Exp. No: Date:
SINGLE PHASE FULLY CONTROLLED BRIDGE CONVERTER
WITH R AND RL LOAD
Aim:
To Study and observe the working and operation of single phase fully controlled bridge
converter with R and R-L Loads and to plot the voltage waveforms across load and thyristors (with
and without freewheeling diode) for different firing angles.
Apparatus:
S. No Apparatus Range Type Quantity
1. Isolation transformer 1 KVA, 230V/ 115-
60-30-0-30-60-115 V
Shell 1
2. CathodeRay Oscilloscope … … 1
3. Load Rheostat 100 ohms/1A Wire
wound
1
4. Inductive Load with
tapping’s
0-50-100mH, ….. 1
5. Silicon Controlled
Rectifiers
12A/600 V TYN612 4
6. 1 fully controlled
bridge converter firing
Kit
….. ….. 1
7. Voltmeter (0-30V) MC 1
8. Ammeter (0-2A) MC 1
9. CRO Probe …. …. 1
10. MCB 230V/6A …. 1
11. Fuse 5A Glass 1
12. Connecting wires … … Required
No
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CIRCUIT DIAGRAM FOR 1-PHASE FULLY CONTROLLED BRIDGE CONVERTER
WITH R LOAD:
CIRCUIT DIAGRAM FOR 1-PHASE FULLY CONTROLLED BRIDGE CONVERTER
WITH R-L LOAD:
TRIGGERING CIRCUIT FOR 1-PHASE FULLY CONTROLLED BRIDGE CONVERTER:
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Procedure:
1. Observe the trigger outputs using CRO.
2. Disconnect the supply as they are proper.
3. Connect the circuit as per circuit diagram and switched ON the supply.
4. Supply the trigger pulses to the respective SCR’s
5. Note the load voltage and load current for different firing angles.
6. Repeat the above procedure for R-L load with and without freewheeling diode.
7. Plot the output waveforms on a graph sheet.
8. Disconnect the supply.
Precautions:
1. Use the fixed terminals of load rheostat.
2. Don’t connect CRO in dual trace mode.
3. Initially keep MCB in ON position.
4. The Power circuit and input must be electrically isolated.
5. Carefully observe waveforms on CRO.
Waveforms ForR-Load:
Waveforms for RL-Load:
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Expressions For Load Voltage And Load Current:
With R – load:
Average load voltage, 1
sindc mV V t d t
cosmVt
1 cosmV
Load current, 1 cosdc mdc
V VI
R R
With R-L Load With continuous mode:
With R-L Load With discontinuous mode:
Average load voltage, 1
sindc mV V t d t
1 cosmVt
cos cosmV
Load current, cos cosdc mdc
V VI
R R
With R-L Load and with freewheeling diode:
Average load Voltage, 1
sindc mV V t d t
= cosmVt
= 1 cosmV
Load current, dcdc
VI
R
= 1 cosmV
R
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Tabular Form:
Load Firing angle
(degrees)
Voltage across load, Vdc
(Volts)
Load Current
Idc
Theoretical Practical Theoretical Practical
R- load
RL – load
RL Load
With
freewheeling
diode
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Result:
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ELECTRICAL AND ELECTRONICS ENGINEERING 27
Exp. No: Date:
SINGLE PHASE AC VOLTAGE CONTROLLER WITH R AND R-L
LOAD
Aim:
To Study the working of 1 AC voltage controller with R and RL Loads and to observe
and plot the voltage waveforms across load and SCR for different firing angles.
Apparatus:
S. No Apparatus Range Type Quantity
1. Ammeter (0-1A) MI 1
2. Voltmeter (0-35 V) MI 1
3. CRO …. …. 1
4. Load Rheostat 50 /5A Wire wound 1
5. Inductive Load 0-150 mH/2A …. 1
6. SCRs 12 A/600 V TYN 612 2
7. 1 center tap transformer 100VA, 230/24-0-
24V
Shell type 1
8. 1 A.C. voltage controller
firing circuit
…. …. 1
9. CRO Probe ….. …. 1
10 Connecting wires ….. ….. Required
No.
Procedure:
1. Switch ON the power supply.
2. Observe the trigger outputs of the firing circuit for different firing angles using CRO.
3. Make the connections as per the circuit diagram.
4. Switch ON the triggering pulses to respective SCRs in the power circuit.
5. Plot the output voltage waveforms across the load and SCRs for different firing angles.
6. Repeat the above procedure for R-L load (with firing angle being greater than power factor) and
draw the output waveforms.
7. Disconnect the supply.
Precautions:
1. CRO should not be used in dual trace mode.
2. Use fixed terminals of load rheostat.
3. An isolation transformer should be placed between power circuit and input.
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CIRCUIT DIAGRAM FOR 1-PHASE A.C. VOLTAGE CONTROLLER
WITH R-LOAD:
CIRCUIT DIAGRAM FOR 1-PHASE A.C. VOLTAGE CONTROLLER
WITH RL-LOAD:
TRIGGERING CIRCUIT FOR 1-PHASE A.C. VOLTAGE CONTROLLER:
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Waveforms for R-Load:
Waveforms for RL-Load:
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Theoretical Calculations:
Tabular Form:
Firing angle
(degrees) Voltage across load, 0 rms
V
(Volts)
Load Current
Irms
(Amps)
R- load
RL – load
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Result:
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Exp.No: Date:
SINGLE PHASE STEP DOWN CYCLOCONVERTER WITH R AND
R-L LOADS
Aim:
To Study and observe the operation of 1- Step down cycloconverter with R and RL loads
and to plot the voltage waveforms across the load and SCRs for different firing angles.
Apparatus:
S. No Apparatus Range Type Quantity
1. SCRs 12A/ 600V TYN612 4
2. 1- Center taped step-down
transformer
230/9-0-9v,1A,18VA ---- 1
3. Load Rheostat 145 / 2.8A Wire Wound 1
4. Inductive load (0-150mH), 2A ….. 1
5. Cathode Ray Oscilloscope,
CRO Probe
…. …. 1
6. 1 Step down cyclo converter
Triggering Circuit Kit
…. ….. 1
7. Voltmeter (0-30V) MI 1
8. Ammeter (0-200mA) MI 1
9. Main Circuit Breaker 230V/6A … 1
10. Connecting Wires ….. …. Required
no.
Procedure:
1. Switch on the main supply to the firing circuit.
2. Observe the test points and trigger outputs by changing frequency division and by varying firing
angle, using CRO.
3. Switch OFF the supply to the firing circuit.
4. Make the power circuit connections as per the circuit diagram.
5. Connect the firing pulses from the firing circuit to the respective SCRs in the power circuit.
6. Switch ON the circuit breaker.
7. Switch ON the supply to firing circuit and the main supply.
8. Set the frequency division to ‘3’.
9. Vary the firing angle potentiometer and observe the waveforms across the load and note down
the readings of voltmeter and ammeter.
10. Repeat the experiment for different firing angles.
11. Switch OFF the supply to the firing circuit and main supply.
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CIRCUIT DIAGRAM FOR 1-PHASE STEPDOWN CYCLO CONVERTER:
TRIGGERING CIRCUIT FOR 1-PHASE STEPDOWN CYCLO CONVERTER:
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ELECTRICAL AND ELECTRONICS ENGINEERING 34
Precautions:
1. As the output is zero even after all the connections made properly, MCB is switched off and
A.C. input connections to the power circuit are interchanged. This is done to synchronize
firing circuit and power circuit.
2. The frequency division is changed only when the trigger pulse switch is at OFF position.
3. Load Rheostat is connected in the circuit with its fixed terminals only.
4. CRO is not used in dual trace mode.
Waveforms:
Theoretical Calculations:
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RL Load:
Output Voltage,
1
2 2 2
0m
rms
V SinV d
1
22 2
2 22
mV Sin Sin
Tabular Form:
Voltage across the load
0 ( )V volt
Load current
Io(Amps)
Theoretical Practical Theoretical Practical
R-Load
R-L Load
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Result:
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Exp. No: Date:
THREE -PHASE HALF CONTROLLED BRIDGE CONVERTER
WITH R & RL LOAD Aim:
The aim of Experiment is to analyze the operation (Switching) of three phase halfcontrolled converter with resistive and inductive load using VPET-218 module.
Apparatus:
Procedure: Connection procedure:
1. Connect the module to single phase ac supply through power chords. 2. Connect the three phase ac input to the connection provide on the module. 3. Connect the three phase ac input to R, Y, B, N terminal of the PI connector for trigger pulse
generators. 4. Connect the trigger pulse output from isolation transformer to the SCR gate cathode using
pulse patch cards. 5. Connect the external RL load across input terminals of the module.
6. Connect the CRO across the load.
Experimental procedure:
1. Switch ON the power supply to the module.
2. Switch ON the pulse ON/OFF switch SW and check waveforms at various test points.
3. Vary the firing angle step by step in range (0-120)
4. For each vary the firing angle observe the output waveform though the CRO. 5. The output voltage calculated from the above given formula and measured values are
tabulated as shown. 6. The various waveforms are plotted on the graph.
Service tip: 1. Verify firing circuit waveforms at least point with respect to ground.
2. If all test point waveforms are not available much output power supply regulator. 3. Check whether 24V ac input it is not 24V step down transformer may fault.
S.NO Apparatus Quantity
1 VPET Module 1
2 Pulse Patch
Chords
As per Required
3 R-Load 1
4 RL-Load 1
5 CRO 1
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Circuit diagram:
Model Graph:
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Tabular Form:
S.No Firing Measured Output Calculated
Angle Voltage Output
Voltage
Result:
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Exp. No: Date:
SINGLE PHASE INVERTER WITH PWM CONTROL.
Aim:Study of single phase PWM Inverter firing circuit Apparatus Required:
S.No
Apparatus
Quantity
1
PWM Inverter Kit
1
2
CRO
1
3
Patch Chords
As per
Required 4
RL-Load
1
Procedure:
1. Make the connection as per the circuit diagram.
2. Connect the gating signal from the inverter module.
3. Switch ON D.C 24 V.
4. Keep the frequency knob to particulars frequency.
5. Observe the rectangular and triangular carrier waveforms on the CRO.
6. Obtain the output waveform across the load Rheostat. Precautions:
1. The voltage applied should not exceed in the ratings of the diode
2. The diodes will be connected correctly
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Circuit Diagram:
Model Graph:
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Result:
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Exp. No: Date:
SINGLE -PHASE DIODE BRIDGE RECTIFIER WITH R LOAD
AND CAPACITANCE FILTER. AIM: - To calculate the ripple factor of a bridge rectifier, with and without filters. APPARATUS:-
S.No Apparatus Quantity
1 Experimental Board 1
2 Diodes, IN4007 4
3 Resistor, 1KΩ 1
4 Capacitor, , 100μF/25v 1
5 Transformer, (12-0-12v) 1
6 MultiMate’s 2
7 Connecting Wires As per Required
Procedure:- 1. Connections are made as per the circuit diagram. 2. Connect the ac main to the primary side of the transformer and secondary side to the bridge
rectifier. 3. Measure the ac voltage at the input of the rectifier using the multi meter. 4. Measure both the ac and dc voltages at the output of the Bridge rectifier. 5. Find the theoretical value of dc voltage by using the formula.
Precautions:- 1. The voltage applied should not exceed in the ratings of the diode 2. The diodes will be connected correctly
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Circuit Diagram:
Without filter:
With filter:
Model Graph:
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Calculations: Theoretical calculations:
Vrms = Vm/ √2
Vm =Vrms√2
Vdc=2Vm/П (i)Without filter:
Ripple factor, r = √ ( Vrms/ Vdc )2 -1 = 0.482 (ii)With filter:
Ripple factor, r = 1/ (4√3 f C RL) where f =50Hz
C =100µF RL=1KΩ
Practical Calculations:
Without filter:
Vac=
Vdc=
Ripple factor, r=Vac/Vdc
With filter:-
Vac=
Vdc=
Ripple factor,r=Vac/Vdc
Observations: Without Filter:
Vm Vac Vdc Ripple factor
Without filter:
V1 V2 Vm Vac Vdc Ripple factor
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Result:
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Exp.No: Date:
Forced Commutation Circuits
Aim: To study the forced commutation circuits of Class A, Class B, Class C, Class D & Class D.
Apparatus: 1. Forced Commutation Study Module
2. Rheostat-50Ω/1A, 360Ω/1.2A.
3. Loading Inductor
4. CRO
5. Connecting wires-As per Required
Circuit Diagram:
For Class A Commutation: Waveforms:
Procedure:
1. Connections are made as per the circuit diagram.
2. Connect trigger output to gate and cathode of SCR.
3. Switch ON the supply to power circuit and observe the voltage waveforms across Load,
Thyristor and capacitor by varying the frequency potentiometer.
4. Repeat the above procedure for different values of R, L & C.
5. The output waveforms are plotted on graph sheet.
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For Class B Commutation: Waveforms:
Procedure:
1. Connections are made as per the circuit diagram.
2. Connect trigger output to gate and cathode of SCR.
3. Switch ON the supply to power circuit and observe the voltage waveforms across
Load, Thyristor and capacitor by varying the frequency potentiometer.
4. Repeat the above procedure for different values of R, L & C.
5. The output waveforms are plotted on graph sheet.
For Class C Commutation: Waveforms:
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Procedure:
1. Connections are made as per the circuit diagram.
2. Connect T1 and T2 gate pulse from the firing circuit to gate and cathode of thyristors
T1 and T2 and observe the waveforms across R1 and R2 by varying the duty cycle.
3. The output wave forms are plotted on the graph sheet.
For Class D Commutation: Waveforms:
Procedure:
1. Connections are made as per the circuit diagram.
2. Connect T1 and T2 gate pulse from firing circuit to corresponding SCR in power circuit.
3. Initially keep trigger circuit at OFF position to charge the capacitor. This can be
observed by connecting CRO to the capacitor.
4. Now trigger circuit is kept ON position and note down the voltage waveform at different
duty cycles.
5. The output wave forms are plotted on the graph sheet.
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For Class E Commutation: Waveforms:
Procedure:
1. Connections are made as per the circuit diagram.
2. Connect trigger output to gate and cathode of SCR.
3. Switch ON the supply to power circuit and observe the voltage waveforms across
Load, thyristors.
4. The output waveforms are plotted on graph sheet.
Precautions:
1. Before making the connection, check the components.
2. Keep the knobs in minimum position.
3. Working conditions of all the equipment’s must be checked properly.
4. Check the fuses and terminals.
PSCMR college of Engineering and Technology
ELECTRICAL AND ELECTRONICS ENGINEERING 52
PSCMR college of Engineering and Technology
ELECTRICAL AND ELECTRONICS ENGINEERING 53
Result: