Triac Driver

Have you checked out the data sheet sample circuits that every phototriac, photomosfet devices have?.

Have you considered using an off-the-shelf solid state relay? Depends of course on the size & type of motor, and what kind of control you need. More information would be helpfull.

What sort of motor? What sort of control? On/off, variable speed?

I have an Inductive Motor that is used for a Kitchen Hood. I want just ON/Off the motor . i have designed a circuit with MOC3063(Opto Coupler with Zero Cross Detector) & BT139 (Triac) . It works well with a Lamp. but when i replace the lamp with this motor , it doesn't work correctly, and when i stop triggering the triac(after 2-3 times) it will continue working and will be hot! , i've read somewhere that i should use SNUBBER network with R-C , but i dont know values for R & C . i have tested with 100 ohm for R and 0.1u for C. but the Capacitor is burning up!

"Omid"

......... Phil

You appear to be making the solution to your problem more difficult than it really is. There is a whole heap of info describing on-off motor control at the press of a Google button. For instance this is one of the first items I found;

While the values you selected for your snubber will most likely work, the important question is what type of resistor and capacitor, along with their ratings, did you select?

The capacitor MUST be at least 250Vac rated X2 class and the resistor must be able to handle the peak voltage. I would recommend you use at least a 1W carbon film resistor (generally a 350V rating) which you will find at Jaycar, same as for the X2 capacitor.

What is X2 class? what's it's name known in the market?

These capacitors are self healing, flame retardant items for connection directly between The Line (A) and Neutral (N) wires of the mains supply.

They are generally described as EMI/RFI suppression capacitors. They are usually rated in Vac (in your case 250Vac) and will be marked X2.

If we disregard the low impedance motor winding in series with the Triac, the snubber capacitor is connected directly across the Triac in series with a low value resistor. It will therefore be essentially directly across the mains supply.

Heres one type available from RS Components

That link is not correct it seems. I should have checked it.

Anyway, here is the manf's data sheet for one type of X2 cap

RS Components and other suppliers will have it or an equivalent.

"The Real Andy"

Do the world a favour.

......... Phil

Try your own advice hypocrite.

Thank you All!!!

My Circuit finally worked with your help.

I used X2 Class Cap(0.01u 400V) and R (4W - 170 Ohms) and it works correctly! Thanks again.

"Omid"

......... Phil

Why 10nF (0.01uF) capacitor and not 100nF (0.1uF) and why 400V (I assume it was 400Vac)? Much bigger (physically) than needed.

And where do you get a 4W, 170 ohm resistor pray tell? Standard value would be 180ohm.

What type is the resistor, metal film/oxide, carbon film, wire-wound? You only need a 1W carbon film.

BTW are you in Australia where we use 240Vac, 50Hz?

it would pay to consider the worst-case peak pulse power (and energy) the snubber resistor sees, which is Vcap^2/Rsnubber, with

if the triac turns on at peak line, the snubber cap will (assuming time constant