Block Bell wiring

[Tonycardall]

I'm using block bells in order to pass trains through my Absolute Block sections, along with the fully interlocked lever frame. A slight problem. When using the bells there was interference with the LEDs in my Megapoints Controllers panel for my fiddle yard. It appears that there are spikes created that cause the LEDs to flash alarmingly.
Following advice from a friend I fitted diodes across the coils and that cured the LED issue. However, it now appears that there is insufficient oomph and it is not possible to ring the codes fast enough. One has to leave at least a second between strikes which is a bit hopeless.
Any ideas? I should mention that I have similar electronics skills to my metalworking skills!

[Alan Turner]

Which way round have you fitted the diodes?

regards

Alan

[Tonycardall]

Which way round have you fitted the diodes?

Alan, my ignorance is exposed already. I have six bells and, if I remember correctly, on the basis that I don't know which direction the power comes in from, I merely tried them using crocodile clips until I found a way that stopped the interference with the LEDs.
Tony

[Tim V]

What volts and what are you driving the strikers with?

[davebradwell]

We also need to know the current rating of the power supply if it's one of the 'plastic block" types. The diode should have blown up when you connected it across the solenoid in the forward biased direction so that may be a clue. I'm assuming you could rattle the bells as fast as you liked before the diode. Just to be clear the end of the diode with a line should go to the positive supply terminal so that it is reverse biased and will catch the spike when you release the button. You might also check current rating of your switch, assuming, of course, that you know how much current the solenoid draws. My guess is that the power supply is shutting down because the diode is the wrong way round and is a dead short - difficult to know without seeing it so could be way off the mark.

DaveB

[Tonycardall]

Which way round have you fitted the diodes?

Thanks to the responses I am now feeling that I ought to have checked the diodes orientation prior to starting this thread rather than assuming that I had everything right and imagining that there was some other problem. Having revisited my bells and checked that a) the diodes are all the correct way around and b) with them corrected I'm not getting this worrying flashing of LEDs on my Megapoints control panel, I now have all 4 Thompson & Co bells working perfectly with no LED problems.
That leaves me with the cuckoos in the nest. For reasons of expediency I bought two random bits of kit that probably have no place in my BR(W) box and they refuse to play no matter what I have tried. I think that the Block Instrument with incorporated bell is of LNWR origin. The bell I have no idea about.

(When previewing this post the pics are side on but when exploding the images they come out correct. I'll post this and then edit if still wrong.)
I have them wired so that they work well enough but with two oddities. No matter where I have placed the diodes, they continued to effect the LEDs and also, when hitting the tapper on the 'bell' the stikers on both instruments are activated. This doesn't happen the other way around.
The simplest, though most expensive option, is to replace the bell with a Thompson and replace the combined block instrument/block bell instrument with a 1947 Block instrument and a Thompson bell.
Any thoughts other than 'get you wallet out' would be most welcome.
Tony

[JFS]

Hello Tony,

Just to mention that your wires might be a bit on the thin side (compare them to what was originally fitted by by the previous owners!). This could be causing a fair voltage drop around the layout and might explain why a wrong-way diode did not blow!

Best Wishes,

[grovenor-2685]

Are you trying to use the original wiring scheme?
Can you draw out the wiring you have done so we can see the circuit?
It should not be neccessary to buy more.

How did you overcome the delay you were describing previously?

[Tonycardall]

Just to mention that your wires might be a bit on the thin side

Howard, I would have thought you and Keith have learnt your lesson after the locking frame project. I'm nothing if not ambitious!
You won't believe this, and in view of you mentioning wire size I should probably keep it to myself, but I'm using telephone multi cable. This on the basis that, a) it was free as it was left over from a rewiring scheme at Bath Road Depot and found it's way to my house about 35 years ago, (how can it have been so long ago?) and b) it has lots of pretty coloured wires so that I could easily identify the correct one at each end of the 9 yard run.
Perhaps I should start again with some heavier duty cable.

Are you trying to use the original wiring scheme?

I was doing my best to follow this diagram. Albeit with a change that may or may not be significant. The first set of bells that I bought had a link installed between terminals C and E rather than C & L as per the diagram. I have done the same in all of my other bells and that is the only way that I can get it to work. I also have a wire running from C to C in the adjacent boxes. The more I type the more concerned I get BUT, as previously stated, all of the Thompsons work although I get the spiking on the LEDs.


I think that I am going wrong at the LNWR block instrument end where, instead of C, L, Z and E there are terminals 1 -12. The bottom three (1, 2 and 3) being the bell circuit terminals.

Tony

Para 2 edited to give greater 'clarification' (!?)

[Brian Eves]

See my attached document for a simple block bell circuit

[grovenor-2685]

I think that I am going wrong at the LNWR block instrument end where, instead of C, L, Z and E there are terminals 1 -12. The bottom three (1, 2 and 3) being the bell circuit terminals.

The internals of your boxes, in respect of the bells should be as Brian's diagram. Normally there should be one battery at each box, not going to both boxes as you show it but the effect is the same. Comparing your diagram with Brian's then your L is his XL and should connect to the common of the tapper, your Z should be his X connected to the pressed contact of the tapper, your E his XB and connected to the bell then the normal contact of the tapper. If E and Z are swapped, ie Z goes to the bell that reverses the polarity, the bell won't care but your diode will.

Are you implying that your box includes the commutator and needle as wel, ie the C connection is for the blockl?
Since you don't have to worry about the cost of several miles of wire on poles I would recommend seperating the bell circuits from the rest of the instrument. Makes life easier.

[Tonycardall]

See my attached document for a simple block bell circuit

Brian, Thank you. I'll start off by using your circuit diagram on two instruments that I am happy with and do a bench test before starting on the final location. I'll let you know how I get on.
edit insert. This is curious. I have rejigged things on my bench using your diagram and I regret to inform that I get no action at all. I have L to L which thanks to Keith I understand is XL to XL on the diagram. Also, using a separate battery for each set I have negative from the battery to Z or your XL and positive to XB which is my E.
The only way that I have got them to work is by placing an additional link C at box A to C at box B and then a further link from C to E in each box.
None of this uses any logic, it's just how I had it working previously by trial and lots of error.

Are you implying that your box includes the commutator and needle as wel, ie the C connection is for the blockl?

Keith, Yes all in one instrument. I thought that I had an elegant, neat solution using old S&T telephone wires all tidily in the wrapper but you and Howard are obviously right, I need a separate run of heavier duty wires.
Thanks as ever.
Tony

[Brian Eves]

I found this drawing amongst my archive.
It appears to be more in line with your diagram

[grovenor-2685]

I need a separate run of heavier duty wires.

I doubt the wire size is a problem unless they are very long.
You do need to know the wiring inside the box, if the C terminal goes to the bell as in Brian's latest diagram and there is an XR (Bell relay) then a diode across the bell is not much use, you would need it across the relay. And you need to know as well the circuit for the rest of the block instrument. I think you have to bite the bullet and trace out all the internal circuitry, and ideally measure the resistance of the bell and indicator coils, and relay coils as well if there are any. Without that its all guess work.
I have added the basic bell circuit to your diagram, but its no use if the internals on yours are different.

[grovenor-2685]

The standalone bell in the bottom two photos only seems to have E, C and L, no Z. That suggests E for the + battery/bell connection and probably c is the common return, you should be able to trace those wires easily enough.
The combined instrument in the other 2 pics is more of an isueas the wiring between tapper, bell and the terminal block is not visible in the photos and you will likely have fun tracing it out.

[Tonycardall]

The standalone bell in the bottom two photos only seems to have E, C and L, no Z. That suggests E for the + battery/bell connection and probably c is the common return, you should be able to trace those wires easily enough.
.

Keith, You would think so! However, although I've traced the Z to the rear of the case, if I connect the positive to E the striker is immediately energised. I can get it to work to a degree, in that the striker in the other box operates, by putting positive to C and connecting E in A box to C in B box. I also, again, have to link C to E in box B. However, When using the tapper in A the strikers in both boxes strike! The same does not happen in reverse.
and I thought that drawing up the locking plan was difficult!!!

Tony

[grovenor-2685]

All that demonstrates that the internal wiring is not as supposed so the only way to resolve it is to trace out the wiring.
Sorry

[Tonycardall]

All that demonstrates that the internal wiring is not as supposed so the only way to resolve it is to trace out the wiring.
Sorry

Thanks Keith
Tony

[Tonycardall]

All that demonstrates that the internal wiring is not as supposed so the only way to resolve it is to trace out the wiring.
Sorry

Keith,
You were spot on. The rear connection is superfluous in a simply wired bell system. C is negative feed and, once again, I needed to bring C from the other bell to E along with the positive feed and it all works. I'm still using the diodes across the coils to prevent the spikes but I think I'll leave it alone now as everything appears to be working perfectly. I've ordered some heavier duty cables to replace the telephone wiring that I'm using at present but that will have to wait as I have other things to work on, such as sorting out some version of AJ's for my automatic uncoupling.
Will I ever learn?
Regards,
Tony

[grovenor-2685]

Well done, I would not worry about changing the phone wire, these don't take much current and are designed to be miles apart, small wires are fine when they are close together.