Hi Rob,
Nice to hear from you, and your timing is actually quite good. I assumed many of the regular contributors we're either out for the holidays, or dealing with the ice storm. You must of gotten some of that up your way?
I selected the 24V relay mainly because I have this source readily available (water pump, freezer), and it didn't rely then on the inverter, but I may have introduced some additional factors. I had isolated the relay from everything on the turbine, powered it up, and then put a nominal 120VAC reference source into it. With the power supply applied, and no input voltage across V1, 2 or 3 to COM, the relay actuated. As soon as I connected the input reference, the relay went off; not alarm state, but the Green LED relay light went out, and the relay opened (continuity between 11 &12; 11 & 14 open). This is what led me to where I am now.
I also noted that the supply voltage "has no polarity when a DC current input is used." In my case A1 was negative, and I could always see the reference voltage across V2 and A1.
With regard to AC vs. DC you raise a really good point. And, the main reason I wanted a diode rectifier is that over the years I've had individual diodes fail and lightning (I believe), and they are much easier to test and replace (vs. a potted bridge). Still, our turbine is 16-pole, so to even get to 20 HZ we're spinning 157 rpm. My concern is that from start up to cut-in (0 to 12HZ) the relay may not respond. In our case we'd have the parking brake on, and never get up to speed. I guess I should check this to be sure though.
It look like the "range" on V3 is 0-600V, even though the "measuring voltage" is 60-600V AC/DC, so I should be able to switch to V3 as you've suggested. Initially I thought we'd be out of the (low) range since with no wind our reference voltage is ~36 V. With your inverter protection scheme(s), you probably don't have either low frequency or voltage as a concern?
I may try to contact a rep at Omron, but I wasn't sure how much help they'd offer, being this is a one-off project.
For now, we're running. It was p a i n f u l waiting these last few days for a breath of wind. This morning we saw upwards of around 1.2 kW, so I'm pretty excited. For now it won't be operating without supervision.
Thanks for taking the time to respond, and initially for sharing your schematic. I think it is a sound approach. Just need to work thru the details in our case.
Kind regards, ~ks