[Boatanchors] Relay Repair - Demagnetization Question

[Jim Haynes]

I'm trying to remember now the name of an item - might have been
"armature stops" that were a Bell System issued item.  Consisted of
a thin piece of brass and a loop of paper to hold it against the
pole piece of a relay to prevent the armature from sticking.

Then there are the "telephone type" relays.  Some of them allow the
armature to contact the pole piece, but others have a brass screw
called a "residual screw" through the armature to stop it a certain
distance from the pole piece.

I guess it was about 1960 that some clever people decided to take
advantage of the situation and make relays with magnetically-hard
materials in the core so they would intentionally stay operated
without current in the windings.  A pulse of current to operate
the relay and a pulse in the opposite direction to release it.




jhhaynes at earthlink dot net