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Contol Speed Of AC Motor Using TRIAC

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the_balistic

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Hii guys,

Need your help and suggestion

First I'm making Project for controling Speed of AC Motor using Visual Basic 6.0 and

AVR, I use bascom avr or codevision avr as my compiler. I don't have problem with

interfacing microcontroller to PC.

For controlling speed of the motor I used MOC3021 and TRIAC for Drive the motor.

I wanna ask, How we can microcontroller detect zero crossing? so I can trigger the TRIAC at optimal time. Here Is MY Circuit Please Check




So what do you suggest. What methode control should I use and can you give me the algorithm (please don't post a source code)
 

Any reason, why you don't follow the circuit suggestion from MOC302x datasheet? Using no gate series resistor looks dangerous.
 

Okay , thanks for the advice, I will try it. But can you suggest me the algorithm
 

Guys,

I've already make the Zero Crossing Detector to detect when we have to fire TRIAC

I use proteus for my simulation. I use Signal 12VAC and the use optocoupler to detect the zero crossing.




After I realized that Signal AC is 50 Hz sot it meas one periode of AC signal is 20 ms, and divided into 2 is 10ms. So I must fire the triac after I detect the zero crossing with maximum time fire is 10ms, am I right?

What I wanna ask, when you want to speed up the motor? the time to fire TRIAC is shorter or longer after zero crossing deteced?

Does anyone has simulate TRIAC and MOC3021 in proteus? Can I see the scematic, and how long the pulse periode you use?
 
hi this is kumar and present i am doing final year project related to electrical motors i.e speed control of an inductuion motor using triac please send and also using in this micro controlleer 89c2051 and in this progarm for microcontroller is as to be there so please send program and description or some material

Added after 2 minutes:

reply please to my email:kumar.diet@gmail.com
 

hi there!

i have question.. if i try to omit the zero detector.. and instead switch through program at approximate times... would there be any problem... i have to achieve control of speed only for 4 -5 sec and then i will be using full speed.

Added after 28 seconds:

speed control at start up and stop only...
 

the_balistic said:
Guys,

I've already make the Zero Crossing Detector to detect when we have to fire TRIAC

I use proteus for my simulation. I use Signal 12VAC and the use optocoupler to detect the zero crossing.




After I realized that Signal AC is 50 Hz sot it meas one periode of AC signal is 20 ms, and divided into 2 is 10ms. So I must fire the triac after I detect the zero crossing with maximum time fire is 10ms, am I right?

What I wanna ask, when you want to speed up the motor? the time to fire TRIAC is shorter or longer after zero crossing deteced?

Does anyone has simulate TRIAC and MOC3021 in proteus? Can I see the scematic, and how long the pulse periode you use?
Click to expand...
:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x:-x
Hi Ajay y dont u use Pulse transformers from Lajpat Rai market as ur project is so valuable
 

the_balistic said:
Hii guys,

Need your help and suggestion

First I'm making Project for controling Speed of AC Motor using Visual Basic 6.0 and

AVR, I use bascom avr or codevision avr as my compiler. I don't have problem with

interfacing microcontroller to PC.


For controlling speed of the motor I used MOC3021 and TRIAC for Drive the motor.

I wanna ask, How we can microcontroller detect zero crossing? so I can trigger the TRIAC at optimal time. Here Is MY Circuit Please Check




So what do you suggest. What methode control should I use and can you give me the algorithm (please don't post a source code)
Click to expand...







hi friend.......................... i am working on same project ,i am using pic microcontroller i also use ZCD to contol firing angle of triac ....i suugest u make seperate hardware of ZCD then then take its output as intterupt to controller
 

What methode control should I use....
Click to expand...
Phase Firing Angle is good for AC load. Search for it.

What I wanna ask, when you want to speed up the motor? the time to fire TRIAC is shorter or longer after zero crossing deteced?
Click to expand...

The shorter the firing delay after ZCD, the more power will be delivered to the load. If you want to speed up the motor, decrease the delay.

- - - Updated - - -

For inductive load, you will also need a snubber circuit.
 

ArdyNT said:
Phase Firing Angle is good for AC load. Search for it.

- - - Updated - - -

For inductive load, you will also need a snubber circuit.
Click to expand...
Can anyone suggest a snubber ? Actually I am trying to control a 2hp motor with BT139 Triac and MOC 3021 Optocoupler.
I had controlled successfully speed of an exhaust fan motor using triac. For zero crossing detection I actually connected the live wire to the interrupt pin of the microcontroller via a 1M resistor and ground is also connected to neutral via a 1M resistor. I know it is not the best way to get the work done but this was what was suggested by the application notes provided by Atmel. And the best thing is it works.....
 

ArdyNT said:
Phase Firing Angle is good for AC load. Search for it.



The shorter the firing delay after ZCD, the more power will be delivered to the load. If you want to speed up the motor, decrease the delay.

- - - Updated - - -

For inductive load, you will also need a snubber circuit.
Click to expand...

how to introduce delay?
 

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