So, this is a new design, but some of the background is covered in a previous thread: http://forum.allaboutcircuits.com/threads/ltspice-simulation-of-dual-ssr.112263/ I'd like to design a dual-pole SSR circuit which will be incorporated into a larger board with custom features. The other aspects are not locked in yet, and should be manageable for me, but the high power switching is new territory for me, so I wanted advice. I've got the circuit below working as planned in simulation, and it intuitively makes sense to me, but I was hoping you all could help me in case there are problems I'm overlooking. The resistor and inductor at the far right are meant to represent a 1/3HP AC motor. The motor would run on 200-250VAC, sometimes split-phase, sometimes single-phase. The control signal into the optos would be 5VDC. The key requirement that differentiates this circuit from more standard triac/SSR circuits is that we want BOTH power legs to the motor cut off when the 5VDC signal is absent. Please let me know what I've got wrong - I imagine there's plenty! Thanks in advance!