Triac Driver

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I want to control an Electrical Motor that works with 220 V AC.
have you any sample circuit that uses Triac,PhotoTriac and Zero Cross
Detector OptoCoupler for this purpose?


Re: Triac Driver


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

Re: Triac Driver



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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.
--
Regards,

Chas.

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Re: Triac Driver



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

Re: Triac Driver


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!


Re: Triac Driver



"Omid"
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** You MUST use a mains rated cap like this:

http://www.dse.com.au/cgi-bin/dse.storefront/4410f441098d3542273fc0a87f9c06c3/Product/View/R2628




.........   Phil



Re: Triac Driver



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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;

http://www.fairchildsemi.com/an/AN/AN-3006.pdf

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.


Re: Triac Driver


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


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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
http://www.rs-components.com.au/electronic-components-au/index210.html

Re: Triac Driver


On Sat, 11 Mar 2006 11:25:29 GMT, Ross Herbert

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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
http://www.evoxrifa.com/cap_catalog/emisuppr/pme271me.pdf

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

Re: Triac Driver



"The Real Andy"

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** Why don't you go top yourself -  you asinine, drunken FUCKWIT.

    Do the world a favour.




.........  Phil



Re: Triac Driver


On Tue, 14 Mar 2006 08:40:03 +1100, "Phil Allison"

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Try your own advice hypocrite.

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Re: Triac Driver


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.


Re: Triac Driver



"Omid"
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**  We think it 'mazing ......





.........  Phil





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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?

Re: Triac Driver


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

if the triac turns on at peak line, the snubber cap will (assuming time
constant << 20ms) be charged to 240*sqrt(2) = 340V peak. the 170R
resistor sees 678W peak. the time constant is 1.7us, current is an
exponential decay, so is power (with half the time constant)

a carbon- or metal-film 1W resistor probably wont like that; eg a 1W
PR01 has a single-shot pulse of 500W at 1.7us, so can be relied upon to
fail, probably straight away. a PR03 can cope with repetitive pulses if
D < 0.2%. worst-case the triac triggers every cycle, so D = 1.7us/10ms =
  0.02%, so a PR03 would be fine.

carbon composition resistors are good for this job; see also IRC's CHP
series of parts. a CHP 1 (0.36" x 0.1" dia) smt resistor would eat this job.

a w/w resistor usually has a hefty overload rating; a 1W AC01 would also
do the job. best not to think about how the inductance of the snubber
resistor can bugger up the snubber though.

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Cheers
Terry

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