Electromagnets for AJ couplings

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ChrisMitchell
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Electromagnets for AJ couplings

Postby ChrisMitchell » Mon Aug 09, 2010 6:12 am

I've reached the conclusion that as I get older, switching to some sort of autocoupling is inevitable, so I thought I'd have a go at using Alex Jacksons (anyone recommend anything else??).

Are there any recommendations for electromagnets which can be readily purchased. Everything I've read talks about ex PO relays or winding your own.

regards, Chris

Pannier Tank
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Re: Electromagnets for AJ couplings

Postby Pannier Tank » Mon Aug 09, 2010 8:09 am

Hi Chris,

Try MSE http://www.modelsignals.com/couplings_frame.htm they do a PK MAG uncoupling electromagnet.
Last edited by Pannier Tank on Tue Aug 10, 2010 1:11 pm, edited 1 time in total.
Regards

David

hughesp87
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Re: Electromagnets for AJ couplings

Postby hughesp87 » Mon Aug 09, 2010 7:37 pm

Hi Chris,

Having tried the 'wind your own' version on my current layout, I'm finding that performance is a bit hit and miss, as the strength of the magnetic field is clearly not consistent. You may therefore get more consistency out of a purchased item, and I'd be interested in your findings.

However, the other option is to use a permanent magnet that is physically moved up and down under the trackbed by some form of lever mechanism. The idea was suggested by Gerco van Zetten in Snooze 164 p32, and having seen them in operation on his P87 demo at the convention in the Netherlands last year, I can vouch for the fact that they produced a very positive movement of the coupling every time. Less wiring too, although there's more construction time in the mechanism. I may well be trying this myself in an attempt to find faultless operation under exhibition conditions.

Regards,

Geraint
Geraint Hughes
Cromford & High Peak in P4
Danish Railways in P87

nigelcliffe
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Re: Electromagnets for AJ couplings

Postby nigelcliffe » Mon Aug 09, 2010 8:28 pm

Simple mechanism to move a fixed magnet - a Servo, cost about £2.50 (or less).

Suitable control circuits available on-line, or a board which will control four is available for a fiver from MERG which works with four on/off switches, or a little more if wanting DCC control of the magnets. This latter option opens up the possibility of mapping the magnets to unused function keys so they can be worked easily whilst driving (I've done this).

craig_whilding

Re: Electromagnets for AJ couplings

Postby craig_whilding » Mon Aug 09, 2010 10:41 pm

If you go with the MSE magnets put them in the ballast between sleepers rather than under the board or something as you wont be close enough otherwise.

Suitable transformer is the Maplins VN10L at 1200mA running at 9V.

This combination has been used successfully by me with hinged and flexing variants on mineral wagons so far.

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Flymo748
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Re: Electromagnets for AJ couplings

Postby Flymo748 » Tue Aug 10, 2010 4:36 am

Pannier Tank wrote:Hi Chris,

Try MSE http://www.modelsignals.com/couplings_frame.htm tehy do a PK MAG uncoupling electromagnet.


There is also one from Gaugemaster. It's a bit more expensive though.

http://www.gaugemaster.com/item_details ... ster%20EM1

<watch the wrap>
I have a couple of them at home to try out, but no views one way or the other yet.

HTH
Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

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Dave K
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Re: Electromagnets for AJ couplings

Postby Dave K » Tue Aug 10, 2010 7:41 am

Pannier Tank wrote:Try MSE http://www.modelsignals.com/couplings_frame.htm tehy do a PK MAG uncoupling electromagnet.


I've been experimenting with one of these on my test track with some mixed results. Most of the problems stem from the dropper being too short and the electromagnet won't pull it down - even when set at 12v. But when the dropper is set, at the recommended, 9mm (for wagons) they work well, even on wagons fitted with DC1 brake gear where the operating rod between the two DC handles limits the amount of movement.

martin goodall
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Re: Electromagnets for AJ couplings

Postby martin goodall » Tue Aug 10, 2010 3:01 pm

I may be in a very small minority, but I just can't get on with Alex Jackson couplings. They are a very elegant design, but they are so susceptible to maladjustment that their reliability suffers significantly as a result.

After fiddling around with various commercial couplings I eventually devised my own design of magnetically operated auto-coupling, which I call the "Burford" coupling (currently awaiting publication in MRJ).

I don't know how to upload any of this material onto this website, so if anyone wants details, please e-mail me (see the Membership List) and I will be happy to forward a comprehensive datasheet, complete with drawings and a selection of photos.

I have found these couplings relatively easy to bend up from wire and 100% reliable, whereas I never achieved that level of reliability with any other couplings.

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grovenor-2685
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Re: Electromagnets for AJ couplings

Postby grovenor-2685 » Tue Aug 10, 2010 4:23 pm

I don't know how to upload any of this material onto this website,

There is a place here for asking :)
But all you have to do is just look down below the box you are typing in, click on the "Upload attachment" tab, browse for your file and then click "Add file" , repeat as necessary then submit your message.
Regards
Regards
Keith
Grovenor Sidings

martin goodall
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Re: Electromagnets for AJ couplings

Postby martin goodall » Tue Aug 10, 2010 8:04 pm

This is just a page of photos, but the system says the file is too large to upload.

I'll try with the .pdf version :

Couplings - Pics for data sheet.pdf
(190.99 KiB) Downloaded 409 times



I hope it's there. (I can't see it on the screen.)

martin goodall
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Re: Electromagnets for AJ couplings

Postby martin goodall » Tue Aug 10, 2010 9:02 pm

The photos seem to have uploaded successfully, so here are the instructions for the 'Burford' coupling (288 KB as a .pdf file):

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ChrisMitchell
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Re: Electromagnets for AJ couplings

Postby ChrisMitchell » Thu Aug 12, 2010 6:16 am

Thanks everyone for the advice. next question is where to put the electromagnets assumnig I try AJs. Here's the trackplan of my little layout - West End - all of 1.5m long

West End.jpg
West End.jpg (9.63 KiB) Viewed 7720 times


The simplest as far as I can see is electromagnets at A and B which allow for runnning round a train at the platform and also for shunting the two sidings. However, would it also be better to consider adding eletromagnets at C, D or E for the individual sidings?

Thanks

Chris

nigelcliffe
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Re: Electromagnets for AJ couplings

Postby nigelcliffe » Thu Aug 12, 2010 8:29 am

Whether you need the extra magnets (eg. C) depends on how you plan to shunt wagons along the sidings.

For example, if four wagons are to be dropped in C, pre-split into two groups of two, then the single magnet at B will be enough. Later you can come back and collect two of the wagons (pre-split).
But, if you need to spread the wagons along the siding C, perhaps two at a (hypothetical) loading dock near the buffer, and two others at a coal staithe nearer to the turnout, then you either deliver the wagons in two separate shunting moves, or you need a way to uncouple the last two at the coal staithe having previously left two (split with uncoupler B) at the loading dock.


This complexity is one of the reasons why I started to put the control of couplers inside locos (and in some pieces of stock), not under the track, though the primary reason was difficulty in finding magnet A in your diagram (and watching layouts with "hunt the magnet" moves).


- Nigel

martin goodall
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Re: Electromagnets for AJ couplings

Postby martin goodall » Thu Aug 12, 2010 7:54 pm

This does underline the one disadvantage of advance uncoupling. If you rely on one or two magnets at or near the throat of a yard you will have to keep shunting backwards and forwards to detach wagons and push them back to the place where you want to leave them - something that would never have happened on the prototype.

For this reason, I put magnets at all the places on my layout where I wanted to leave wagons, except where they will be propelled beyond the last magnet in the sidng to be left further down that siding. [This is discussed in more detail in the data-sheet I uploaded a couple of days ago - see above.]

The alternative of the DCC-controlled coupling hook is ingenious, but its one drawback is that it is fittted only to the loco, which means that you can only use it to uncouple between the loco and the vehicle next to it, unless you fit some of these DCC-controlled hooks to some of the other vehicles as well, which might be as expensive and time-consuming as putting some additional electro-magnets under the track.

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ChrisMitchell
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Re: Electromagnets for AJ couplings

Postby ChrisMitchell » Thu Aug 12, 2010 8:09 pm

Thanks Nigel and Martin. Definitely sounds like I should end up with plenty of magnets - I think l will need two on the longest siding, but then may not need one at B.

regards, Chris


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