I am looking to build or buy a capacitive discharge circuit to use with my Atlas switch controllers and motors. Can anyone provide me with a link to the correct version to use with an HO layout. Does it matter which AC specs I have on my power source.
I am using a 15Volt AC 3 amp AC adpater to power the snap Atlas motors. It gives a good kick and I have never had a problem in three years, but I wish to avoid a possible sticking controller as I'm told this is likely.
Also, can I build my own bridge rectifier and where would it go in the circuit?
Thanks for any hints.
Aaaaa Cisco
I used www.awrr.com/cdsupply.html and it has worked great.
have fun.
Lee
There is a CD unit called the Snapper. I think it is made by Circuitron. I installed one on my clubs layout after the buttons on the control panel had jammed burning out several machine coils. If I remember right it was about $24. Works great, no more burnouts. Uses the AC accessories power from your power pack, puts out DC to throw the machines. Easier than building one.
I think that's the same diagram I used to build mine, or one very similar.
Your AC power supply should be fine. That would substitute for "T1" in the diagram.
The bridge rectifier is the 4 diodes assembled in a diamond pattern. I would suggest simply buying a bridge rectifier when you buy the resistors and capacitors.
The "optional ready circuit" in yellow just powers an indicator light.. Unless you like building stuff like this, it just adds complexity. You can skip it.
It takes an iron man to play with a toy iron horse.
Try this link:
http://home.cogeco.ca/~rpaisley4/CircuitIndex.html
MisterBeasley The bridge rectifier is the 4 diodes assembled in a diamond pattern. I would suggest simply buying a bridge rectifier when you buy the resistors and capacitors.
Thanks for the tip. I see several bridge rectifiers listed at my LHS website...from 140 ma to 1/2 amp and 1 amp. Are any of these values correct....but more importantly, where and how in the circuit does the bridge rectifier go????
retsignalmtr There is a CD unit called the Snapper......... Uses the AC accessories power from your power pack, puts out DC to throw the machines. Easier than building one.
There is a CD unit called the Snapper......... Uses the AC accessories power from your power pack, puts out DC to throw the machines. Easier than building one.
Thanks for the tip. I looked it up and it is now $29. Well, the price list for the part for making one is about the same, so I think I will order this one.
I have always used a separate circuit with an additional power transformer to power my snap switches. I imagine I can just insert the circuit between this and the barrier strip that sends power out to all the switches.
Hmm, a capacitor, transistor, diode, and a couple of resistors shouldn;t cost near $29 even is buying from Radio $hack. I built one years ago from the book "Practical Electronic Projects for Model Railroaders" by Peter Thorne and it is closest to the first one under "Current Blocking Switch Machine Power Supply" on Rob Paisley's site. 5 components. Super easy beginner electronic project. The one in Thorne's books is slightly different, I don;t have the book handy but it does NOT have a bridge rectifier on the input yet I ran it from the AC terminals of an old power pack. It's so simple I didn;t even build it on a circuit board - I mounted the transistor in a heat sink (also available from Radio Shack) and soldered the parts right to the terminals. It still works but I don't use solenoid switch motors anymore. I built it for my last N scale layout when I got tired of the sticky contacts burning out the fragile Atlas motors.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker Hmm, a capacitor, transistor, diode, and a couple of resistors shouldn;t cost near $29...... --Randy
Hmm, a capacitor, transistor, diode, and a couple of resistors shouldn;t cost near $29...... --Randy
Yes, I see now that the link to which I was referred in the earlier post was for a more comprehensive power supply circuit with LED indicators and included the purchas of a transformer, for which the author suggested $20 to $30. But that is not the simple CD circuit which would be cheaper, as you suggest.
Another question.........I see an indication in one diagram of what the author calls large current surges.....so is the typical tiny gauge wiring [22 or smaller] of an Atlas switch machine (and of the telephone wire I used to connect to them going to be a problem when hitting them with the jolt from a capacity discharge circuit?
Cisco
The surge of power to the switch motor does not hurt the tiny windings in it so the wiring to the motor won't be effected. The power pulse to the motor is very short duration and nothing has time to heat up.
Enjoy
The best thing about CD power supplies is that the capacitor is not re-charged unitl after the control button is released. A shorted pushbutton will not burn up the switch machine coils.
Thanks to all. I am making headway now. I'm glad I found out about this remedy.
Just one remaining question. Mister Beasley has suggested a bridge rectifier in the circuit.
1. I see values of < 1 amp to 1amp in the hobby supply store. What value do I need?
2. (This will seem silly to you all) ........... Where does it go?
can't answer point 1. For point 2, the rectifier goes between the AC supply and the CDU. it'll turn the AC power into straight DC before being fed to the capicitors.
Assuming you're building the rectifier, attach the AC supply to points 1 and 4 (top and bottom) of the diamond. The DC supply will then be fed to the CDU via points 2 and 3 (centre).
Pic (borrowed from wikipedia):
-Dan
Builder of Bowser steam! Railimages Site
Due to the high inrush current a value of 1 amp should be OK.
Check here.
http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#30
D
I just looked at the Toy Train Heaven site. They have the snapper for $21.