Electromagnetic Uncoupling That Works!

[Gary S]

If the electro magnet just causes a car with steel weights to roll a little when the magnet is energized, that would not be much of a problem, much better than using two hands to uncouple cars or using a permanent magnet with the problem of nuisance uncoupling. My system would be operated by anyone in the club participating in an operating session, so I would like it to be fool proof. One other question, would the rolling caused by steel weights in car pull the couplers away form the magnets so that they would not uncouple? It suddenly dawns on me that a flat weight like used by Athearn or steel weights mounted in the center of the car could cause the couplers to move past the magnet or cause an uncoupled car to "follow" the train and recouple when it cleared the magnet.

Russ, it was about 4 years ago that I was perfecting the system, so I don't remember exactly how the steel-weighted cars reacted, although it was definitely adverse.

The best thing to do would be make a mock-up track and then play around with the system. You'd need a Kadee o-scale e-magnet, a pushbutton rated for a couple amps, a power supply, and some track. Maybe take a 1 x 4 and cut a hole in it, mount the magnet underneath, spike several lengths of flex track to the board, and then do some practice uncoupling runs with various cars and methods. I like my 24 volt system because 24 volt DC relays are easy to find. As I mentioned previously, you could use 12 volts on the system, just put the coils in parallel instead of series (Note: it is important to make sure the current flow is going in the same direction in both of the coils). With the mock-up, just use the pushbutton to energize the magnet, don't worry about a time delay. Just experiment to see if the rolling cars are too much of a hassle.

The 24 volt series coil arrangement pulls about 1.5 amps. Parallel at 12 volts would pull about 3 amps. Your power supply would have to be able to handle that. Maybe you have an old power pack that would serve for the experiment?

Do you have any part numbers for the time delays, and do you know of a time delay that would energize for 5 seconds and then do a forced de-energize for 30 seconds before being allowed to activate again?

I don't know of a time relay that would do that function, but a simple combination of two "ON" delay relays and two "regular" relays would accomplish that. As for part numbers, that would depend on the voltage you will be using. Let me know.

If you decide to do the experiment, let me know, I'd be happy to lend technical support and wiring diagrams.