[GreenKeys] Model 15 Selector Magnets

[Jim Cooper]

On 20 Jan 2021 at 17:02, ad7i wrote:

> causes current to be routed away
> from the pulling magnet and to the
> holding magnet, 

basic mis-understanding of the concept !!

A machine has only ONE type of selector magnet...
EITHER a pulling or a holding selector magnet. 

As described in other replies, you can tell by 
looking for the cam on the main shaft which 
PUSHES the selector armature against the 
selector magnet face -- that is the HOLDING 
type.  Without the cam, it's the pulling type. 

The holding magnet concept increased the 
useable range a lot, but also allowed the use 
of 20mA loop current rather than 60mA.  

w2jc