Question on toggle switches for wiring block sections.

[Birds]

I will be starting to wire my new layout in blocks for two train operation.

I was looking at Mouser for toggle switches and ran into a switch configuration I don't understand: On-None-On vs. On-Off-On.

I don't know how the "None" in an "On-None-On" differs from "Off" in an "On-Off-On" switch.

NKK sells a 15A rated SPDT switch in both configurations http://www.nkkswitches.com/pdf/stogglesmedcap.pdf

 

I want to have the power to the blocks be a choice of: throttle A, throttle B, None (off)

What would be the correct choice for this type of setup, or would both work the same?

1. SPDT On-Off-On
2. SPDT On-None-On

(SPDT instead of DPDT because it is a choice between two throttles from a single transformer)


Thanks,

Chris 

[jefelectric]

Birds,

You want the ON-OFF-ON.  The none means there is no middle possition.  The switch goes from on to on without stopping in the middle.

[lionelsoni]

You wouldn't need to go to a DPDT anyway with multiple transformers:  Just connect the transformer commons together.

(It's a good idea to have the transformer outputs in phase with each other, to minimize the arcing and fault current if you should accidentally run over the gap between blocks controlled by different outputs.)

[Birds]

Thank you very much for the replies.

Chris