Triacs are not well suited to inductive loads without the proper support
components.  You would have slightly better luck with SCRs, but you really need
to include a snubber circuit.

For this particular application, relays really are the best way to go.  If you
needed to switch the AC waveform in some special way, then triacs are great, but
this application is just yelling for relays.

If you are unfamiliar with snubber circuitry, pick up some solid state relays,
which will have this built in.  You can get 3 amp versions from radio shack.
You should also consider getting ones with built in zero-crossing detector,
which will minimize the line noise created when switching the motor on.

-Adam

Francois Robbertze wrote:
>
> Hallo again to all PicList members,
>
> I have difficulties switching a forward and reverse 220V AC bi directional
> motor with a pic, triacand optocoupler combination!
>
> The motor is a typical electric sliding gate opener motor - three wires -
> neutral, live(forward) and live(reverse) with a starting cap between forward
> and reverse.
>
> The obvious way is to use two relays. The one relay control the direction
> and the other one switch the current...
>
> I want to do it without relays!!!!
>
> I have connect  two MOC3011 optocouplers  and  two IT416  triac's to a pic
> to
> control this motor, but this configuration damage the two IT's......
> I can connect either forward or reverse, but not both!!
>
> (It seems like the back EMF from the oposite direction switch the motor on
> in the opposite direction as well and the motor just vibrates - not sure)
>
> Attached is a unscrambled version of the layout...
>
> Can someone help?
>
> Kindest regards
>
> Francois Robbertze
> fr10@mweb.co.za
>
>   --------------------------------------------------------------------------------
>                 Name: TRIAC.txt
>    TRIAC.txt    Type: Plain Text (text/plain)
>             Encoding: quoted-printable

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