Jump to content


Google Ads are only seen by non-members of RMweb - Create an RMweb account and you'll only receive modelling ads.

Posted Image What was your favourite model of 2017? Cast your vote


Photo
- - - - -

DC wiring Block control or conventional isolating sections





  • Please log in to reply
122 replies to this topic

#101 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 27 September 2017 - 14:27

Oh for goodness sake. Context context, mine where made in the context of low voltage ac/dc


OK, so I suppose computers don't count either?

Google Ads are only seen by non-members of RMweb - Create an RMweb account and you'll only receive modelling ads.

#102 Chimer

Chimer

    Member


  • Members
  • PipPip
  • 692 posts
  • LocationPortsmouth (Southsea actually!)

Posted 27 September 2017 - 15:28

Oh for goodness sake. Context context, mine where made in the context of low voltage ac/dc

 

OK, so I suppose computers don't count either?

 

I think the US and North Korea are more likely to reach an understanding than you two.  It's got worse than "in advance" and "in rear"!


  • Friendly/Supportive x 1
  • Funny x 1

#103 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 27 September 2017 - 15:48

I think the US and North Korea are more likely to reach an understanding than you two.  It's got worse than "in advance" and "in rear"!


Who said we wanted to reach an understanding? ☺

#104 Ron Solly

Ron Solly

    Member


  • Members
  • PipPip
  • 649 posts
  • LocationEvanston Gardens, South Australia

Posted 27 September 2017 - 23:25

I've begun the presentations. thanks for the feedback on cab control

That is good. Any chance we here on RMweb can get to read it - I assume you have something written out so the memory doesn't fail you at the wrong time.



#105 Pete the Elaner

Pete the Elaner

    Member


  • Members
  • PipPip
  • 1,514 posts
  • Location30 minutes from London on the WCML

Posted 27 September 2017 - 23:58

I've begun the presentations. thanks for the feedback on cab control

I hope they are well received. This will make you feel it was time well spent.



#106 Junctionmad

Junctionmad

    Member


  • Members
  • PipPip
  • 1,310 posts

Posted 28 September 2017 - 00:58

That is good. Any chance we here on RMweb can get to read it - I assume you have something written out so the memory doesn't fail you at the wrong time.


I'll put the PowerPoint presentation when I complete the series in late October into the public domain , no problems with that

#107 Junctionmad

Junctionmad

    Member


  • Members
  • PipPip
  • 1,310 posts

Posted 28 September 2017 - 01:04

I hope they are well received. This will make you feel it was time well spent.


Yes they are very appreciative in fairness , it's not something the club is great at , disseminating knowledge , so it's a start. The first session was on soldering , wire selection guides, connector strategy , common components ( switches, resistors, capacitors , leds and diodes ) , and AC safety.

Next session , is basic DC Wiring one controller per track , isolation sections , insulfrog , electrofrog,

Session 3 covers common return and cab control , reversing loops

Session 4 , wiring for DCC, frog juicers , intro to layout busses and automation

#108 Pete the Elaner

Pete the Elaner

    Member


  • Members
  • PipPip
  • 1,514 posts
  • Location30 minutes from London on the WCML

Posted 28 September 2017 - 02:09

For me, this is what a club should be all about.

I learned a lot from my time as a club member in the 80's/90's, particularly with wiring a layout.

A couple of weeks ago, I was operating a friend's layout at an exhibition & we were next to the person who I learned most of my wiring methods from. We still get on well so I got a guided tour of the layout wiring, which is something the public don't get (or never ask) to see.

It was interesting to see our similarities & differences.


  • Like x 1

#109 DavidCBroad

DavidCBroad

    Member


  • Members
  • PipPip
  • 2,071 posts
  • LocationCotswolds England

Posted 28 September 2017 - 13:25

Vehicle wiring was mentioned, most car wiring was common ground with the return being through the body structure.  Everything was the same polarity.  Earth (ground) in cars is the return, not to be confused with mains earth if you have visions of a long and active life.  



#110 Junctionmad

Junctionmad

    Member


  • Members
  • PipPip
  • 1,310 posts

Posted 28 September 2017 - 14:03

Vehicle wiring was mentioned, most car wiring was common ground with the return being through the body structure. Everything was the same polarity. Earth (ground) in cars is the return, not to be confused with mains earth if you have visions of a long and active life.


Just to be clear. Common ground is different to common return. Common ground is very common in electronics

Ground of course is not confused with earth , ground is the common reference point in a circuit from which voltages are referenced. , earth is the stuff outside your door. Earth ground is a ground referenced to earth

#111 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 29 September 2017 - 21:23

Just to be clear. Common ground is different to common return. Common ground is very common in electronics

Ground of course is not confused with earth , ground is the common reference point in a circuit from which voltages are referenced. , earth is the stuff outside your door. Earth ground is a ground referenced to earth

 

Er, well, not actually :)

 

Unless you are referring to a political decision there's no such thing as "commom ground". There is "common", also known as "common return" ('cos it  returns the current for several circuits) and there is "ground" which is usually, but not always, synonymous with "earth". "Common" may or may not be connected to ground/earth.

 

There is a lot of confusion because the terminology seem to morph to describe particular applications. One good example is the "positive earth" v "negative earth" terminology that refers to cars. Unless they have wheels with gigantic spikes that penetrate deep into the ground cars are definitely not "earthed". They should really be described as "positive chassis" or "negative chassis", but it's a bit late to change that now.



#112 Pete the Elaner

Pete the Elaner

    Member


  • Members
  • PipPip
  • 1,514 posts
  • Location30 minutes from London on the WCML

Posted 30 September 2017 - 00:56

They should really be described as "positive chassis" or "negative chassis", but it's a bit late to change that now.

That would be a lot more accurate but there are other examples of abbreviations which are wrong. 2 annoying ones spring to mind:

 

PIN number.. A common expression but wrong because it stands for Personal Identification Number number. It is either a PIN or a PI number.

AC/DC current: I was taught at school that this is a bad phrase because the C already stands for current. Our teacher told us that if he ever said it, we should all shout Crackerjack! (You will need to be of a certain age to understand this). When he eventually let slip & someone responded, the whole class went silent for a couple of seconds, then when the penny dropped, we all had a good laugh.


  • Agree x 1

#113 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 30 September 2017 - 01:13

That would be a lot more accurate but there are other examples of abbreviations which are wrong. 2 annoying ones spring to mind:

 

PIN number.. A common expression but wrong because it stands for Personal Identification Number number. It is either a PIN or a PI number.

AC/DC current: I was taught at school that this is a bad phrase because the C already stands for current. Our teacher told us that if he ever said it, we should all shout Crackerjack! (You will need to be of a certain age to understand this). When he eventually let slip & someone responded, the whole class went silent for a couple of seconds, then when the penny dropped, we all had a good laugh.

 

Redundancy is a terrible thing ;)

 

Over here the police and news people frequently say something like, "he was traveling at a high rate of speed" which is complete mumble-speak. Speed is a rate. But now I'm really swerving off-topic.



#114 Junctionmad

Junctionmad

    Member


  • Members
  • PipPip
  • 1,310 posts

Posted 02 October 2017 - 00:11

Er, well, not actually :)
 
Unless you are referring to a political decision there's no such thing as "commom ground". There is "common", also known as "common return" ('cos it  returns the current for several circuits) and there is "ground" which is usually, but not always, synonymous with "earth". "Common" may or may not be connected to ground/earth.
 
There is a lot of confusion because the terminology seem to morph to describe particular applications. One good example is the "positive earth" v "negative earth" terminology that refers to cars. Unless they have wheels with gigantic spikes that penetrate deep into the ground cars are definitely not "earthed". They should really be described as "positive chassis" or "negative chassis", but it's a bit late to change that now.

Andyid, I don't know what your profession is , but it certainly isn't electronics

Ground in electronics , is an arbitrarily reference point , usually labelled GND. it's shown as IMG_0098.PNG in schematics ( and yes this symbol originally meant earth ground put its habitually used in electronics to mean GND

GND may be or may not be anywhere near earth potential , in most small dc circuits GND , is actually floating.


The term common GND , is widely used , the term " common return " is not widely used in electronics ( a google search on " common return " will bring up references to model railway usage )

In electronics , a common GND , or spoken as " a common ground " means a single reference point used throughout a single circuit . Many circuits will have different GNDs , analogue , digital etc. even if they are ultimately referenced to each other

On the other hand a " common return " , is less widely used, and typically means using a single path to return currents from multiple circuits

I'll not engage in your idiotic semantic tussles any more , I'm too long at my profession to be led astray by attempts at diversion, deflection and word trickery.
  • Agree x 1

#115 DavidCBroad

DavidCBroad

    Member


  • Members
  • PipPip
  • 2,071 posts
  • LocationCotswolds England

Posted 02 October 2017 - 10:04

Its the idea that one wire can be positive for one circuit and negative for another at the same time with Model Railway DC Common return which makes our brains hurt.  



#116 Crosland

Crosland

    Member


  • Members
  • PipPip
  • 1,726 posts

Posted 02 October 2017 - 13:30

Anyone using a single symbol to represent Earth or even "habitually to mean gnd" would quickly be sent for retraining in any company worth working for :)

 

There are multiple, well established, symbols for different sort of "earth" or "ground" or "0V". There's a good introduction here http://digital.ni.co...6256BE5006F04CF then you can add noiseless, protective, ...


  • Agree x 1

#117 Chris M

Chris M

    Member


  • Members
  • PipPip
  • 482 posts

Posted 02 October 2017 - 14:44

That would be a lot more accurate but there are other examples of abbreviations which are wrong. 2 annoying ones spring to mind:
 
PIN number.. A common expression but wrong because it stands for Personal Identification Number number. It is either a PIN or a PI number.
AC/DC current: I was taught at school that this is a bad phrase because the C already stands for current. Our teacher told us that if he ever said it, we should all shout Crackerjack! (You will need to be of a certain age to understand this). When he eventually let slip & someone responded, the whole class went silent for a couple of seconds, then when the penny dropped, we all had a good laugh.


And PAT testing.
  • Agree x 2

#118 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 03 October 2017 - 04:38

I'll not engage in your idiotic semantic tussles any more ,

 

Thanks. I'm hoping you'll put me on "ignore".



#119 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 03 October 2017 - 16:54

Its the idea that one wire can be positive for one circuit and negative for another at the same time with Model Railway DC Common return which makes our brains hurt.


David,

I think that's the main reason why a lot of people don't like to use common return. It's best not to "over-think" it. There are a few simple rules and if they are followed CR works perfectly well.

Andy

#120 Chimer

Chimer

    Member


  • Members
  • PipPip
  • 692 posts
  • LocationPortsmouth (Southsea actually!)

Posted 03 October 2017 - 17:33

Of course, when you go the other way it's actually "common supply" really ........ :bomb_mini: 


  • Funny x 1

#121 Crosland

Crosland

    Member


  • Members
  • PipPip
  • 1,726 posts

Posted 03 October 2017 - 19:41

Of course, when you go the other way it's actually "common supply" really ........ :bomb_mini:

 

The blue wire on a DCC decoder :)



#122 Ron Solly

Ron Solly

    Member


  • Members
  • PipPip
  • 649 posts
  • LocationEvanston Gardens, South Australia

Posted 03 October 2017 - 22:45

Iain Rice in his book  Railway Modelling The Realistic Way - Chapter 5  Layout Electrics page 127 describes Cab Control.



#123 AndyID

AndyID

    Member


  • Moderated Status
  • PipPip
  • 1,449 posts
  • LocationPacific Northwet

Posted 04 October 2017 - 02:15

... then you can add noiseless, protective, ...

 

and if that's not enough there are always virtual earths. (Not to be confused with "virtually earthed".)









Google Ads are only seen by non-members of RMweb - Create an RMweb account and you'll only receive modelling ads.