This 10-Volt DC 1946 glass-encased relay made the lights alternate “40 to 45 flashes per minute”.
In the trackside signal cabinet it sat on springs and has two electromagnet coils which alternately energize and attract a pivoting armature.
A thick metal bar athe top of the coils spans from the LEFT coil’s metal core to a MIDDLE metal “core” to the RIGHT coil’s metal core. The MIDDLE “core” has metal washers stacked on it. They affecthe flash rate.
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When the LEFT electromagnet energizes, it pulls the LEFTside of the armature up, the LEFT relay contacts close and a separate contact inside the relay basends currento the RIGHT electromagnet.
When the RIGHT electromagnet energizes enough, it pulls the RIGHT side of the pivoting armature up, the RIGHT relay contacts close and the separate contact inside the basends power to the LEFT electromagnet.
There is no timing circuit. Why does it not flip-flop rapidly?
Does it take time for an electromagnet to develop full magnetic flux?