SPEED CONTROL OF 1-Φ INDUCTON

MOTOR USING A TRIAC

SUBMITTED BY: GROUP NO: 14

ABHISHEK SHIVHARE 081113013 ASHWANI KUMAR AHIRWAR 081113042 MD JAWED HUSSAIN 081113057 SUSHIL DAYMA 081113062 B.B.HARISH REDDY 081113065

INTRODUCTION • Single phase induction motor are small motors

having a wide field of usefulness where a poly phase supply is not available. They are generally used in fans, blowers, washing machines, refrigerators, etc.

• The speed of the induction motor can be varied in a narrow range by varying the voltage applied to the stator winding.

• This method of speed control is suitable for such applications, where the load varies approximately as the square of speed, such as centrifugal pump drives, fan load.

• The terminal voltage across the stator winding of the motor can be varied for obtaining the desired speed control by controlling the firing angle of the semiconductor power devices(TRIAC in our project) • For any firing angle α the average output voltage across a TRIAC is given by V = (2V’cosα/π) ; V’ is the max voltage provided.

Instruments used

S.no.

Name of the component

Rating Quantity Name of IC

1. Transformer 220/15V-1amp

1

2. Potentiometer 1

3. Resistors 10 kΩ, 1kΩ

11

4. Capacitor 100uf 1

5. 555 timer 1

6. Rectifier 1amp 2 MIC DB107

7. Comparator 1 LM324

8. AND gate 1 HD74S08

9. DC regulated Power supply

5V ,12V

12

Introduction to the circuit

The functioning of the entire circuit can be studied in five parts

1.TRANSFORMER 2.RECTIFIER 3.COMPARATOR 4.555 TIMER 5.AND GATE

TRANSFORMER The transformer in our circuit is a step down

transformer This transforms the 220V input to 15V at 1

amp. It acts as an isolation device between the ac

mains and the electronic circuit.

Rectifiers There are two bridge rectifiers used in the

circuit to rectify the 15V ac . The output from one of the rectifier is filtered

using the appropriate capacitors and is used as a reference to the comparator.

The output of the remaining rectifier acts as the input to the comparator.

The rectifiers used in the circuit are MIC DB107

Comparator The comparator used in the circuit is LM324 The comparator compares the rectified

voltage at the positive terminal with the filtered input voltage at the negative terminal which acts as a reference and hence generates a square wave.

The magnitude of the square wave is equal to the saturation value, and its magnitude is positive when the input voltage is greater than the reference voltage and vice versa.

The resultant output wave forms the input to the AND gate

PIN DIAGRAM OF LM324

INTERNAL DIAGRAM OF LM324

555 timer The 555 timer used in the circuit is in the

astable mode. The resistors R10 and R11 help in varying the

frequency of the output from the comparator , This helps in generating a pulse train used to

trigger the gate of the triac used. The biasing voltage used in the circuit is 5V. The thus generated pulse train is fed to an

AND gate.

AND gate The AND gate used in the circuit is HD74S08. The input of the gate is derived from the

output of the comparator and of the 555 timer.

The AND gate is used to eliminate the negative pulse train.

PROGRESS MADE SO FAR

P SPICE simulation has been completed Bread board testing has been done Working on PCB

THANK YOU