Single phase to Single phase Cycloconverter

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Aim

To observe the working operation of 1-φ to 1-φ Cycloconverter with R and RL loads and to plot the voltage waveforms across the load.

Apparatus Required

☞Trainer kit- Cycloconverter -1 No

☞Patch Chords – Sufficient Nos

☞Load – Internal Resistive Load

☞CRO – 1 No

☞10:1 CRO Probe – 1 No

Circuit diagram

Circuit Diagram for Single phase to Single phase Cycloconverter

Figure: Single Phase to Single Phase Cycloconverter

Procedure

CRO Settings

☞Time (X) Axis : 5ms/div

☞Voltage (Y) Axis : 20V/div

☞Probe : 1:10 CRO Probe is suitable one.

Initial Settings

☞Ensure the 230V Power Supply is in proper with Tester.

☞Ensure the CRO is working properly with probe checking and proper ground line axis.

Mimic Diagram

mimic diagram of single to single cyclo converter

Experiment Steps

☞Switch on the main supply to the firing circuit.

☞Observe the test points and trigger outputs by changing frequency division and by varying firing angle, using CRO.

☞Switch OFF the supply to the firing circuit.

☞Make the power circuit connections as per the circuit diagram.

☞Connect the firing pulses from the firing circuit to the respective SCRs in the power circuit.

☞Switch ON the supply to firing circuit and the main supply.

☞Set the frequency division.

☞Vary the firing angle potentiometer and observe the waveforms across the load and note down the readings.

☞Repeat the experiment for different firing angles.

☞Switch OFF the supply to the firing circuit and main supply.

Note: If the connections are wrong the kit will get damage.

Observation

S.NOTotal Time (ms)F select Position in (Hz)Firing angle (α in Degree)Vo (Volts)
120F= 5072 
2    
3    
4    
5    

MODEL CALCULATIONS

Data from input waveform:

Total Time for one cycle = 20ms For one cycle = 360 ° Calculate for 1ms = 360/20 For 1ms = 18 degree

Calculate α:

Calculate off time of scr from output waveform = eg.4ms Then αvalue is = 4*18= 72degree

Calculate Output Frequency:

Total Time for one cycle (T) = 20ms So, F= (1/T) T in Sec = 1/ (20*10-3) = 50Hz

Model graph

Model graph for Single phase to Single phase Cycloconverter

Figure : input voltage and load voltage

Output Waveform

output waveform for Frequency Select =F
output waveform for Frequency Select =f/2
output wave form for Frequency Select =f/2
output waveform for Frequency Select

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