Ping JL, latching relays.

Yeah, saw that. It's not clear to me how it actually works. Does the left-hand solenoid push or pull?

I've seen some impressive relay logic systems, on ships and cranes and such. Some of IBMs early card machines would do extensive math, all with relays.

One of these days I'm going to have to rework our elevator controls, now all ancient open-frame relays. I suppose I could reproduce the logic with new P&B octal plug-in relays, or buy a tiny IDEC PLC and program that; the PLCs are programmed in "relay logic"!

This is my current fave:

They operate in well under a millisecond. We've used over 3000 so far, no failures. The latching versions are great for signal switching.

John

--- They both pull against separate armature springs. When the left one pulls in it raises the left angle bar which allows the right armature spring to force the moving contact into the fixed contact and lower the right angle bar.

Then, when the pulse into the left coil ends, the left angle bar drops down on the right angle bar and stays there until the right coil is pulsed.

When that happens the moving contact is pulled away from the fixed contact, the right angle bar is raised, and the left armature spring will force the left armature against the inverted 'U' limit stop lowering the left angle bar just enough so that when the right coil is de-energized its angle bar will come to rest on the left angle bar without allowing the contacts to close.

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--- "Ladder Logic", No?

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--- Nice parts.

JF