Automatic coupler disengagement for postwar!

[daan]

Hi guys,
Just made a few changes in my santa fe F3. The coils of the couplers are normally operated by sliding shoes on the underside of the trucks, but I wanted to operate them on every place of the layout.[:p]
I tried 2 possibilities, both work.
1: disconnect your horn and use the contact of the hornrelais to power the coil of the coupler. My horn was rusty and broke down 3 times already. After 3 repairs, the sound was not what it should be. The coils are now connected with the hornrelais. By pushing the hornbutton, the coil activates and the couples opens. On every part of your layout wherever you whish. The only thing you should do is put the power a bit up in neutral.
2: Connect a 24 volts DC relais with the trackpower. The coil of this relais doesn't react on the ac (only hums a bit; doesn't run hot). Even pushing the horn/ bell button doesn't make the relais close.
BUT if you power the tracks in neutral with DC, the coil reacts and opens the coupler!! The position also goes through to the next step!
It needs some filldling with the spring of the relais however to get the right setting. If you have a modern type of coupler use a 9 volt battery to power the coils, they can't handle the voltage of the track.
Both options work flawless, and the santa fe F3 has now an automatic coupler to be operated on any place of the layout, wherever desired.[:0]

I know it means fiddling with a nice engine, but since it's not in collector's condition anymore, I wanted to try the option of automatic coupling.
It should work on any other coiltype coupler without using TMCC or other electronic devices.

What do you think of it??

[lionelsoni]

We're on the same track, Daan, so to speak.

I have a similar scheme in all of my locomotives that have electromagnetic couplers. I have a circuit that charges a capacitor from the motor voltage. But whenever there is a little voltage on the motor field coil, a transistor discharges the capacitor into a relay coil, operating it for a second or two. In normal running, the capacitor stays discharged because the field coil is in use. However, in neutral, the capacitor will charge after a few seconds with the voltage turned up, since the e-unit has disconnected the motor voltage from the motor. Then, the next time the locomotive starts, the capacitor charge is dumped into the relay and the couplers open as the locomotive pulls away.

I mostly use 9-volt DC relays from Radio Shack; but I have recycled some whistle relays into my circuit to operate couplers.

[Anonymous]

I am afraid I'm behind the curve wiring wise....if you left everything hooked up from horn relay (for instance the horn works on the one I'm lucky enough to have) and simply added a second wire to the coupler would it have the same effect (enough power??) only the horn would work as well every time you would want to uncouple??

[Anonymous]

Both are good options, btw, the horn relay idea is just like the prewar switchers with the teledyne couplers. American Flyer used the same type of coil on prewar engines to activate teh reverse unit allowing two trains to run on the same track with different (well somewhat) control.

good work[:)]

[lionelsoni]

Mike, if you're actually talking about a horn, not a whistle, you can't hook them together. The horn runs off 1.5 volts DC from a dry cell, whereas the coupler wants quite a few volts of AC track power. However, it would work with a whistle, which does run off the track voltage.

Dennis, I didn't know American Flyer did it too. Lionel called it "Magic Electrol".

[Anonymous]

Yes the old 1663 switcher, I need one :), good catch Bob,

The horn runs of the 1.5 volt DC, but the relay which the old whistle control operates does run from the DC pulse over the ac track voltage as it is a seperate electrical circuit from the horn power circuit, it just controls when the horn is energized.

Dennis

[Anonymous]

Thank you Bob, my head is on straight now.

[daan]

QUOTE: Originally posted by lionelsoni

We're on the same track, Daan, so to speak.

I have a similar scheme in all of my locomotives that have electromagnetic couplers. I have a circuit that charges a capacitor from the motor voltage. But whenever there is a little voltage on the motor field coil, a transistor discharges the capacitor into a relay coil, operating it for a second or two. In normal running, the capacitor stays discharged because the field coil is in use. However, in neutral, the capacitor will charge after a few seconds with the voltage turned up, since the e-unit has disconnected the motor voltage from the motor. Then, the next time the locomotive starts, the capacitor charge is dumped into the relay and the couplers open as the locomotive pulls away.

I mostly use 9-volt DC relays from Radio Shack; but I have recycled some whistle relays into my circuit to operate couplers.

Also a very clever option! It leaves the horn and whistle functions working too. But I guess you'll need a rectifier before the capicitor. I'll try that option too.. (and pass it on to another hobbyist who's very keen on knowing ways to uncouple his couplers.)

[lionelsoni]

Yes, a rectifier, and a charging resistor so that the capacitor doesn't charge when you make a brief stop in neutral, not intending to uncouple.

I have connected the transistor in two ways. I thought that putting the relay coil between the capacitor and the collector would have the advantage of prolonging the discharge, since the charging resistor would supply a little extra charge during that time. It does; but often it prolongs it indefinitely, when the relay doesn't release at all. This runs the risk of burning out the coupler coil if you don't notice that it is still energized and stop the locomotive soon after uncoupling.

The better way is to connect the relay in series with the capacitor, with a diode across the relay coil to shunt the charging current around it. Then connect the collector just past the charging resistor. This shunts all charging current to ground with the transistor is turned on, so the relay always releases after uncoupling.

Another uncoupling trick that I use is a track switch in the yard lead that leads only to a bumper a few inches away, and an uncoupler section in the yard lead between that switch and the yard throat. When tail switching, I uncouple the last car, then pull forward, shove the rest of the cars into the bumper to close the knuckle, then go back and shove the uncoupled car into the yard.