Page 157 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

EXERCISE 67 : Assess construction of control circuits for

– SCR, DIAC, TRIAC, IGBT

Objectives

At the end of this exercise you shall be able to:
• construct and test a power control circuit using SCR
• assemble and test a lamp dimmer-cum-fan speed regulator using TRIAC and DIAC
• construct and test a power control circuit using IGBT.

Requirements

Tools/Equipments/Instruments
• SCR 2P4M -1 No. • Isolation Transformer 230V, 1A - 1 No.
• Resistor 1K,1/4W -2 Nos. • TRIAC TYN404 - 1 No.
• Resistor 330R,1/4W -1 No. • Heat Sink - 2 Nos.
• Resistor 2.2kΩ/¼ W -2 Nos. • Capacitors 0.5uF,600V - 1 No.
• Wire wound resistor 10k,10W -1 No. • General purpose PCB - 2 No.
• Pot 500k,0.5w -1 No. • CRO 30MHz - 1 No.
• Pot 100k,3w -1 No. • IGBT 5SMV 86M1731 - 1 No.
• LDR -2 Nos. • ON/OFF Switch - 2 Nos.
• LED GREEN 3MM -1 No. • Socket for IGBT - 1 No
• Diode 1N4007 -1 No. • Breadboard - 1 No.
• General purpose PCB -2 Nos. • 12V lamp 5W - 1 No.
• Power supply DC 0-32v -1 No.
Procedure

TASK 1: Assess SCR control circuit for dark sense light

1 Connect circuit as per diagram in Fig 1 Fig 1
2 Adjust the pot 50k to set dark sensitivity required
3 Cover the LDR to make dark condition effect.
4 Remove the cover of LDR to change dark condition of LDR.

5 Observe the LED ON/OFF condition with respect to LDR dark and not dark
condition.

TASK 2: Assess phase power control circuit using TRIAC and DIAC
1 Connect circuit as per diagram in Fig 2
2 Keep the pot 100k to the maximum resistance position.
3 Connect CRO across load terminal
4 Switch on the supply.
5 Vary the potentiometer and observe the waveform across load.

6 Record the output waveform
7 Repeat steps 5 and 6 for further pot settings.

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