A while back, I ran across an intriguing relay variant. It's a single pole double throw relay with two coils, where the contactor normally sits in the middle between the two contacts. In other words, it's normally open, and by triggering one coil or the other you can get it to contact one side or the other.
It's like a single-pole double-throw latching relay (the type with a separate set coil and reset coil), except that it doesn't actually latch - when power is released neither contact is contacted by the contactor.
Is there a common name for this?