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Discussion Starter · #1 ·
Right guys, electrics. Who can explain the following terminology in simple terms for me. (Extract from All Components web site)
1. SPST on-off
2. SPDT C/o on-on
3. SPDT C/o on-off-on
4. DPDT on-on
5. DPDT c/o, c/off on-of-on
6. SPDT for points (on-off-on)
Right I can guess that the last one is a switch for points, and I suspect the 1st one is for isolating sections, and the 5th is the best ones for cab sections, but am not sure. Help would be appreciated, I mean what the hell does c/o mean!!!. Thanks
K
 

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1. Single Pole Single Throw. Just two connections, either on or off.
2. Single Pole Double Throw C/o
C/o = change over
This switch has three connections, one of which can be 'switched' to either of the other two.

3. Single Pole Double Throw C/o 0n-off-on
As 2 with an extra position in the middle (centre off) where nothing is connected.

4. Double Pole Double Throw. This is two of (2) with a single lever. So 6 connections.

5. Two of (3).

6. As 3, but has to be held in either of the end positions or it will return to the centre off position. I.e it doesn't latch in either on position.
 

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C/O is CENTRE OFF Not - change over.

i.e DPDT C/O Is Double Pole (Two sets of electrically independent switch contacts) Double Throw (Makes both ways when fully over) C/O (Centre Off). e.g On-Off-On
SPST Is Single Pole (One set of contacts) Single Throw (Makes only with one other set of contacts in one position) e.g. On or Off.

Hopefully this explains most styles you're likely to encounter:-
 

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Sorry Brian, but to the vast majority of us who've worked in the electrical/electronic world for many years
C/O = Change Over, not 'centre off' - there is, as far as I am aware, no standard abbreviation for this function.
And having bought some of the very same switches keekster64 is asking about, the C/O in the All Componants website definately means 'change-over'.
Regards,
John Webb
 

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QUOTE (Brian @ 25 Oct 2006, 09:41) <{POST_SNAPBACK}>C/O is CENTRE OFF Not - change over.

Hard to explain this one if c/o meant centre off:

QUOTE 5. DPDT c/o, c/off on-of-on

I admit I did puzzle over what the abbreviation meant in this case. I think I can remember seeing both alternatives used --- as John says horribly inconsistent. However selecting change over was the only interpretation consistent with the other information provided (I am a mathematician).
 

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Hi John
Not wanting to get into any arguments here, I too have been in the electrical business for a long time(over 43 years) but in my line of elcetrical work 'C/O' in toggle switch formate, which is what were referring too here, means 'Centre Off'. Change over only applies to relay contacts. All switch that are 'Double Throw change over so there is no need to specify it again!

Anyway, to help I have attatched a picture from my web pages showing the basic toggle switch styles.
Switch Types
 

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Discussion Starter · #7 ·
To help avoid protracted debate here, I guess I need to know which switches for which purpose. Am I right in saying, No.1 is the one to buy for isolating sections, no. 5 is the one for cab switchs, and no.6 is for points. Assuming this is correct what wire connects with each terminal. The first switch is easy, power in from cab switch or controler and then out to the isolated section. As for the cab switch, I'm a little unclear which terminals go where. Thanks for the help so far, very illuminating.
 

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No. 1 - Correct
No. 5 - the centre pair of tags go to the rails- these are connected to the moving contacts in the switch. One controller output goes to the pair of tags on one side, the second controller to the pair of tags on the other.
No. 6 - one side of the power supply (usually 16 volts AC) into the central tag. One outer tag is wired to one coil, the other outer tag to the other coil of the point motor. The other side of the power supply goes straight to the two unused tags on the point motor coils.
The same wiring works for 'Capacitor Discharge Units' which some people prefer for more reliable point operation.

I warmly recommend the several small books PECO produce on wiring up layouts. They have clear coloured diagrams which are easy to follow.
They also explain much better than I can about how cab control can be simplified by 'Common Return' wiring which only needs one wire to each track section and uses switch No. 3 above, with some saving in money and time and effort.
Regards,
John Webb
 

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Discussion Starter · #9 ·
QUOTE (John Webb @ 25 Oct 2006, 22:49) <{POST_SNAPBACK}>No. 1 - Correct
No. 5 - the centre pair of tags go to the rails- these are connected to the moving contacts in the switch. One controller output goes to the pair of tags on one side, the second controller to the pair of tags on the other.
No. 6 - one side of the power supply (usually 16 volts AC) into the central tag. One outer tag is wired to one coil, the other outer tag to the other coil of the point motor. The other side of the power supply goes straight to the two unused tags on the point motor coils.
The same wiring works for 'Capacitor Discharge Units' which some people prefer for more reliable point operation.

I warmly recommend the several small books PECO produce on wiring up layouts. They have clear coloured diagrams which are easy to follow.
They also explain much better than I can about how cab control can be simplified by 'Common Return' wiring which only needs one wire to each track section and uses switch No. 3 above, with some saving in money and time and effort.
Regards,
John Webb]
Thanks a lot John, much appreciated. I do have a few books that show the wiring, and I have figured out most of that as shown on my diagram posted elsewhere, however, I need to be sure of the connections. I intend to use the common return approach, so No.3 sound the way to go. What are the connections for that one?
K
 

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Toggle switches use the central tag as the moving armature (or the contact that's moved by the toggle lever) The outers are the contacts that the armature makes contact to when the toggle lever is in the correct position. So, centre to either left or right tag/s depending on lever position. Don't forget that in most toggle switches the levers position is opposite to the contact thats making. i.e Lever to the left the centre and right tag makes while lever to the right the left and centre make!

For the small extra cost (pence normally) I wouldn't buy SPDT toggle switches. Buy the DPDT version as this gives you an added set of contacts that can be used for other functions if need be. Forward planning perhaps?

My web site link here shows most common toggle switch arrangements Common Toggle Switches In the diagrams the central armature is depiced by the thicker line and the dot (The dot being the armature central tag).
 

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Discussion Starter · #11 ·
QUOTE (Brian @ 26 Oct 2006, 10:46) <{POST_SNAPBACK}>Toggle switches use the central tag as the moving armature (or the contact that's moved by the toggle lever) The outers are the contacts that the armature makes contact to when the toggle lever is in the correct position. So, centre to either left or right tag/s depending on lever position. Don't forget that in most toggle switches the levers position is opposite to the contact thats making. i.e Lever to the left the centre and right tag makes while lever to the right the left and centre make!

For the small extra cost (pence normally) I wouldn't buy SPDT toggle switches. Buy the DPDT version as this gives you an added set of contacts that can be used for other functions if need be. Forward planning perhaps?

My web site link here shows most common toggle switch arrangements Common Toggle Switches In the diagrams the central armature is depiced by the thicker line and the dot (The dot being the armature central tag).
Thanks Brian, making a lot more sence now. A picture speaks a thousand words.
K
 
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