Tuesday 21 May 2019

Magnet uncoupler testing

I mentioned in the previous post about contemplating ordering some of Rapido's Railcrew uncouplers to use on Mt Wilson so that I can have non-permanent uncouplers and trouble-free running. 

Before investing a fair chunk of modelling money into postage from Canada, I thought I'd have a go at testing whether I could replicate the same design concept the Railcrew uncoupler uses with a view to building something similar myself. I bought a 6-pack of 12mm x 3mm rare earth magnets from Bunnings and built a quick test bed from some offcuts of timber and tape.

From left to right are two magnets aligned parallel to the track, then a coaster of roughly the same height to create a level area for the track to run over, then two magnets separated from each other by 1mm of tape, and finally two separated by 5mm. I wanted to see if there was much difference in having the magnets further or closer apart.


The first test with the magnets 1mm apart worked well, uncoupling the TRC and MRC from each other.


Same with the next pair, 5mm apart from each other.


And as predicted, the magnets arranged in line with the track didn't uncouple the wagons. They did push the coupler release bar horizontal though!


I'm planning on using cork on Mt Wilson, so I though I would try out putting the cork coaster between the track and magnets. The couplers appeared to be too far away for it to work.


Time then to test out the on/off function of my plan by taping two of the magnets to the coaster and running a few wagons over it. The photos explain the results.



So that works. I've learned that the magnets need to be right under the track to be strong enough to uncouple the wagons, much the same as Rapido suggests for fitting their uncoupler. Now to work out how to make my own. I'm not particularly confident with electrical wiring despite having muddled through it for Rozelle Street, so I don't really want to operate these via servos if I can avoid it. I'd be ok with a push rod or something similar, provided that I can design it so that "off" is with the knob flush against the fascia so that it doesn't get bumped in transit and as a reminder that the uncoupler is active. More thinking required.

In the meantime, I spent a few hours painting today.


Next job will be tracklaying and wiring, and I'll add the roof and lighting after that.

Cheers,
Ben

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