Fan Speed Control using 8051

Hi,

Does any one know how to control the speed of AC fan.
Its easy to switch ON/OFF the fan through 8051 ports, But how to vary the speed of it,
I m connecting 5 switches to the input of 8051.
1 for ON/ Low Speed.
2 for Low Medium speed.
3 for Medium speed.
4 for High Speed(top).
5 for turn OFF the fan.

But some of my friends told to use TRIAC to vary the voltage.Is it possible.?

Hi,

Does any one know how to control the speed of AC fan.
Its easy to switch ON/OFF the fan through 8051 ports, But how to vary the speed of it,
I m connecting 5 switches to the input of 8051.
1 for ON/ Low Speed.
2 for Low Medium speed.
3 for Medium speed.
4 for High Speed(top).
5 for turn OFF the fan.

But some of my friends told to use TRIAC to vary the voltage.Is it possible.?

kirangowle

yes you can make it using triac see home automation over internet project on this site and use fan speed portion of the code....

Hi Mirza,

Can i have circuit diagram.
Because i have a doubt how to interface controllers 1 pin to Fan.

see this circuit to connect triac with micro...



Cde is Pin which u will connect with your micro controller pin.....

see this link for more info...

Light Dimming with uc and triac

also see this attached document it will help you...

Hi,

We have to use PWM technique to control the gate turn on/off ?.

yes pwm technique will be used with zero crossing detector that will control the firing angel in above diagram MOC is doing this job ......... it is providing isolation and also checking zero crossing....

here is zero crossing points....



first you have to use zero crossing detecting circuit to fire your triac at exact position to cut your A.C wave for fan speed control

Means first i have to detect the zero crossing using comparator,from this i have to connect to 8051 in tern which generates PWM upon zero crossing.

or MOC it self will detect the zero crossing?

Hi,

In this below circuit i m not checking for zero crossing. But when i vary the pulse freq the voltage across bulb will vary.
Is it correct? can i test on Hardware.
How to give 230 V AC in Proteus.

File is here.