Author Topic: Grrr sleepers....  (Read 3883 times)

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Offline cabbage

Re: Grrr sleepers....
« Reply #45 on: Sep 19 2020 19:31 »
Tim, sorry but the assistant is *not* you. I am owed several favours by another "Tim". Who happens to lecture for Messrs Westinghouse. The system is "modern" version of the Westinghouse type "L" system. There is no audible alam sounder(!) Please remember that I am deaf.

The main mimic board sets one of six routes.
The diode logic network on the mimic board then triggers the main power relays to energise the PAIRS of points.
The local control boxes check for the prescence of a loco via axle track conduction i.e. Zero Volt line.
The points move.
Interlocking from the local control boxes selects the correct colour option and sends the previous colour option to the preceeding local control box.

As to the region - the answer is anywhere. Type "L" was sold worldwide and it is the one I grew up on. In the case of my layout block control is a variable distance.

The last set of ring tags have been fixed - now it is down to meter work. And for that - there is nothing to beat a type "7" AVO...

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #46 on: Sep 21 2020 17:01 »
Having spent a highly unenjoyable day circuit testing, I have found that all the leads "buzz out" perfectly. However something has gone wrong with the numbering(?)

I number 0-9 and some of the leads seem to have been numbered 1-10. I think I know the reason for this and I have ordered more ring tags... Thus at the moment we have (0) at one end of the cable and (1) at the other. Following std cabling technique says that even numbered cables are (+), you can see where the problems begin...

There are more cables using 1-10 than 0-9 so I will have to change over to 1-10. Since only one of the four helpers is studying computing I suppose I shouldn't complain(!)

But I do have to say all the colour rainbow coding is totally correct.

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #47 on: Sep 22 2020 11:11 »
This is the loco detection trap. As you can see there is a short length of track insulated from each end. The plastic fish plates have been replaced with the Copper ones. Each fish plate has a flying lead Silver soldered to it. Why Silver solder? Because it gets so cold here in the winter that the Tin changes phase and the joint would crumble - hence the reason all the external electricals are crimped or screwed...

You do *not* want to know the cost of "electrical" Silver solder!!!





This is a close up of the end of the trap.





Time for tea and toasted teacakes!

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #48 on: Sep 24 2020 11:52 »
Yesterday was spent in the kitchen with a hot soldering iron  and A4 sheets my (to others) indecipherable scribble. But after a few hundred crimp clicks and cutter snaps I have reached the point where I have a nearly functional remote power points system.

I am using the Cobolt points motors, but due to Covid I was only able to source a six box of Omega and six box of IP types. This does not matter as both will work via reversing the DC input lines. More stuff should arrive in the post today and I should be able to bring the number of "Power Points" (!) from four to eleven.





Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #49 on: Sep 25 2020 17:45 »
We begin to approach *ON*... The 24 lines from the Mimic board to the distribution hub are now 'in'. The route setting interlock is now on hold as I have run out of relay bases, I need 3 more (5 more on order from eBay).

At the moment it can only "remember" routes 1 and 2.

I am amazed at the subtlety of the original Edwardian design. It is brute force latching relays and dual pole switches but the modules link up sort out the routes and point movement required.

To give you an example of how it functions.

If you press the on button on a piller drill no matter how many times you press it -it still remains on. This is a "memory" function.

You switch on and off the stair lights at either end of the staircase. This is an "either / or" function.

Two switches in series is an "and" function.

Ok it has less processing power than a modern room thermostat - but I am in awe of the original 1910 design team.

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #50 on: Sep 27 2020 12:15 »
Having spent two days being partially deep frozen... The points motors are being screwed to their battens. Giving hopefully a direct pull at the tiebar. The spring clip connections on the base of the motor have been taken off to a "choc block" which makes life a lot easier for me.

The remaining four motors will be fitted after some "topiary" or forestry work to enable me to get at them!!!

This shows the points motor with the flying leads and the choc block. Only one of the three internal switches on the points motor is being used. The first is SPST for indicator LEDs, and the second and third are SPST wired either / or but rated at 3A. I have used only switch three.





This shot shows the module screwed to the batten and wired in.





The knots are used to identify the raw cable. I have used conventional colour codes to identify the functions.

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #51 on: Sep 28 2020 14:44 »
Due to required contortionist movements the remaining three points motors took over and hour and a half each to install.

Windchill factor was also a problem....

Now the hard part begins(!) The last three relays have been screwed down and the first of the diode logic board installed. To my great delight, if asked, it operates the required points to set that route. But, as yet, it doesn't reset...

The logic side of the system is actually rather simple if you have read the text above. The three chains terminate on three conditions:  x AND y ,  x <> y , x NOT y.

At this Dr Brades leaves the room and the friendly neighborhood cabbage returns!!!
 
This is the current (!) State of play.





Regards

Ralph
 

Offline cabbage

Re: Grrr sleepers....
« Reply #52 on: Oct 02 2020 15:44 »
I "think" that I am about one week from "ON". The main problem is keeping track of each module as I link it in. The simple hook up wires are going to have to give way to pukkha buss bars and that means making them...

The logic system works but the row of fifteen DPDT relays takes a little getting used to! Holding the power lead on that part of the circuit when in switching mode can make your fingers "tingle"(!)

The string lights will have to wait as no-one seems to have made the chip that I was planning on using this millenium.

(So much for the updayed and improved 2nd edition).

However a friend in the USofA is researching a moden chip for me.

Tomorro is two days of storm, with nothing else to do I can move apace.

Regards

Ralph



Offline cabbage

Re: Grrr sleepers....
« Reply #53 on: Oct 03 2020 13:24 »
One half of the logic switching is "in" and I feel confident that I can start ordering power cable. Working with power cable is a different thing though! The crimp gun is comming out of hibernation, it is amazing the amount of stuff you gather over the decades...

My normal little set of crimp pliers will work on the switching connections, this baby uses 5 BAR compressed air. It was used for making "gas tight" connections. The force will flatten the Copper and Brass connectors into a unified space free union.

I am told the noise is terrifying (?)

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #54 on: Oct 06 2020 11:52 »
*ON*

The PSU has been connected to the board, the variable Vregs tuned to about 3Volts after a mug of tea and a couple of cheese and chuntney doorstops I will begin linking the output lines to the main buss bar.

Thereafter it is back to the graph paper and doodle the logic diodes required to light the correct routes. These are White and Blue. One aspect is that the LEDs are themselves diodes and thus add their own preferred voltages...

But, this is what the board looked like at 6pm last night when I gave up!





It may look like a psychdelic rats nest but everything is quite logical and almost self documenting.

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #55 on: Oct 07 2020 12:32 »
One of the most memorable photos at Bletchley Park is one of Wrens working the Colossus machines dressed solely in chemise and shorts. Strung between the frames of the Colossus machines are lengths of washing line on which articles of clothing are drying...

Having just mapped out the diode matrix for the string lights, viz: 16+16+36+36+36 that would have been a lot of waste heat from the 2a3 switching triodes that they used.

But solder spats and burns besides - I am getting there!!!

Regards

Ralph

Offline John Branch

Re: Grrr sleepers....
« Reply #56 on: Oct 07 2020 15:06 »
Wrens in shorts and chemise is an infinitely better mental image than a psychedelic rat's nest!
John

Offline cabbage

Re: Grrr sleepers....
« Reply #57 on: Oct 12 2020 11:41 »
Having spent most of the weekend going blind from trying read colour code bands... I feel that I am now in a position to commence final wiring of the route setting system.

The susyem uses whote LEDs to show the four routes out of Brassica to Lowe point. It then uses blue LEDs to show the three routes back to Brassica. However whote and blue LEDs have different strike voltages...

The solution is to work from a known fixed voltage and use dropper resistors soldered to the cathode of each LED.

So far so good!

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #58 on: Oct 13 2020 12:46 »
Taking a break from the soldering iron I ventured outside to the part of my track in the area of the garden called the windtunnel... I tried out the three points motors there and to my delight they work - however....

The somewhat flimsy steel bendy wires simply bent like rubberunder the force required to move the tie bar assembly.

 I made a make-do test using a length of 2mm silver steel rod and that didn't bend and the tie bar moves!

More rod is on order... But if the board works the points should work!!! I will admit to attaching an orange clothes peg to the end of the wire so that I could see it move.

Regards

Ralph

Offline cabbage

Re: Grrr sleepers....
« Reply #59 on: Oct 26 2020 11:17 »
The logic system is in, the leds are in, now to fault find... At the GTG at the weekend it proved that the longest length of wiring worked and the points moved across. Given a couple of good dry days the points motors that need it will have the flimsy spring steel wire replaced with 2mm silver steel rod.

Then there will be some painfully cold days checking over the wiring feeds to the local control boxes for the signal lights. Lying on my back to get at them was OK in the summer...

Regards

Ralph