It's hard to say without any schematics. Is it possible that your FACP alarm contacts are bouncing the control power? How are they normally controlled? Snap action switch? Is the 120VAC from ctl transformers derived from the 208 or a separate circuit? Could there be a zero crossing circuit that is never seeing a zero current? I just dealt with little projectors shining into a film chain but I sure do miss the old days of "Wait Til Your Father Gets Home" and "Lancelot Link, Secret Chimp". Now if I can only stop tapping my foot to cue dots and pointing at the screen on reel changes.
Joe
