[GreenKeys] What is a polar relay?

[Jim Haynes]

Well actually it is not center-off, because normally it is adjusted
so the moving contact is held to one side or the other by pull from
the permanent magnet that is part of it.  This is called "side stable".

As with many other topics, a good book on the subject is one of the
Principles of Electricity Applied to Telephone and Telegraph Work
by AT&T Long Lines.  At least one edition is online, and others are
available through the used book market.



 	---

 	"Ya can argue all ya wanna, but it's dif'rent than it was."
 	"No it ain't! No it ain't!  But ya gotta know the territory."
 		Meredith Willson, The Music Man