Relay interlock: permissive contact, changeover load
8 parts
Two relays with opposite resting states, wired as a genuine interlock. The normally-closed relay sits in the control circuit: its contact passes the mode signal while its own coil is dead and OPENS the moment the trip input energises it, so the trip line can veto the mode line outright. Downstream, the changeover relay's common pin swings between its NC throw (the green standby LED) and its NO throw (the run lamp) and is never on both. Both relays are behavioural: the armature is an instant latch that picks up at 8 V and releases at 0.6× that, with no operate or release time, no contact bounce and no coil inductance modelled.
- V1 6V·5Hz
- V2 6V·13Hz
- RLYN1 400Ω NC
- RLYC1 400Ω
- R1 470Ω
- LED1
- LAMP1 150Ω
- V3 12V
