At 04:40 AM 11/21/96 +0000, you wrote:
>Hello everybody
>
>I have designed a PCB for the company i work for which is used on an
>automatic machine..
>The board has 3 PICs on it (2 16C54 and 1 16C55)
>
>This board interfaces with 3 external power relays.These relays are
>signaled from 3 other reed relays on the board which are
>opto-isolated from the signaling PIC.
>
>When the power relays operate alone (not connected to the machine's
>motor) there is no problem. But when they are connected problems
>start. These three relays control a two speed bi-directional  220V
>motor. At the change of speed or direction the electronic circuit
>seems to be reset (it happens about once in 10 changes).
>
>Can anyone tell me what is happening ?
>
>
>Harry
>
RF spikes... Ran into the same thing with a opto-isolated Traic running a UV
Lamp ballast.  The solution was a RF capacitor between the ballast's output
wires.  Also, the spikes might be coming through the AC line, try running
the Motor on a separate AC circuit from the PIC (different outlet).  If this
is the fix, then you probably need an AC filter between the motor and line
(RC filter mabye).