Wiring a Postwar UCS to an AIU?

Rodger,

please note that I already consulted The DCS O Gauge Companion, Part IV.

It most certainly is in Part IV of the book, on page 75.

You simply have to realize that a UCS track is two, separate, 2-wire accessories. You wire the magnet side as one 2-wire accessory:

Connecting Single Function Accessories

To connect a single function accessory to the AIU, such as the MTH Operating Radar Tower or Operating Rotary Beacon, first locate the two terminals or wires on the accessory. If wires or terminals are designated as Hot or Common, connect the Common wire or terminal to accessory power transformer Common. Otherwise, connect either one to accessory power transformer Common. Connect the second wire or terminal to an AIU ACC port terminal labeled “1” and connect the AIU ACC port terminal labeled “IN” to accessory power transformer Hot.

This and a whole lot more is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!

Barry,

Thank you for your reply.  I had already read the quoted paragraph in The DCS O Gauge Companion.  In the past, I have wired multi-function accessories, such as the four-function 497 coaling station (postwar version), to AIU's; consequently, I am familiar with the process.  Also, I am aware that a UCS is a two-function accessory.

The companion text provides pictorial wiring instructions for some accessories, e.g., the Lionel transfer table and certain manufacturers' switch machines.  I couldn't find a diagram for a UCS, however.

I was hoping that someone could post a diagram so that I could connect the correct terminals to an AIU.  Last night, I experimented with one of my UCS's and determined, what I believe, are the two correct terminals to connect to an AIU.

In any event, thank you again for your response.

Be VERY careful to have the AIU set for momentary, not toggle on-off, or you'll burn out the magnet.

For the uncouple function, use terminal #2 from the left on the UCS for the hot wire.  For the unload function, you'll want to feed common to that terminal.  Just sitting here over my morning coffee, I don't have a UCS at hand to recal the wiring.  It is NOT just connecting 2 hot wires to different terminals.

OK, i just went & dug out a UCS,  For uncoupling, feed hot to #2 (magnet).  For unload, feed hot to #4 and common (ground) to #2.  This will keep the magnet from activating when you unload.

As I think about it, I believe that on an AIU, for each of the 10 accessory channels, #1 is NO (normally open) and #2 is NC (normally closed).  Let's say you want to use Channel A9 for uncouple and A10 for unload.  Connect the IN terminal of A9 to UCS terminal #2.  Connect the IN terminal of A10 to USC #4.  Connect the #2 terminal of A9 to common (ground feed).  Connect the #1 terminals of both A9 and A10 to hot feed. 

Be sure to have both AIU channels set to momentary.  Do not use UCS #1 or #3. 

Thank you very much. I owe you a caboose. Your answers were exactly what I was looking for.

I had determined that terminal #2 needs to be hot or common to accomplish the uncouple/single shoe and unload/two shoe functions. Also, I had discovered, as you pointed out, that simply hooking #2 and #4 to hot won't enable the unload function.

Unfortunately, even after using AIU's since they first hit the market many years ago, I never thought about the ports in terms of NO and NC. Although the O Gauge Companion discusses multiple function accessories, I don't think that I saw an explicit explanation in terms of NO and NC. Obviously, I could be wrong.

I followed your directions exactly. As a result, the uncouple/single shoe and unload/two shoe functions work perfectly. Your help made my day.

Yes, I am keenly aware of using the AIU's momentary contact feature. On several occasions, I accidentally hit "ON" rather than "ACT" to activate an Atlas uncoupler magnet. Each time, a few minutes later, I saw a small white cloud puff from the magnet.

Looking back, seeing the clouds now seems funny, but at the time, I was very surprised and worried about a fire. Nowadays, to make sure that I haven't accidentally hit "ON" rather than "ACT," I always hit "OFF" after activating uncoupler magnets.

FWIW, I created a matrix from your written instructions.  I hope that my matrix is correct.

You don't owe me anything, Bear.  I was glad to help.

It can be useful to think of the AIU in terms of a relay's NC and NO contacts.  It can also be useful to remember that the IN terminals of an AIU, like the center (armature) contact of a relay, can also be used as an OUT.  This can be helpful, for example, if one wants to control a turntable through an AIU which has a DC motor.  Connect the + output of a DC power supply to the NO terminals of two AIU accessory channels.  Connect the - output of the power supply to the NC terminals.  Connect the two motor leads, one to each of the two channels' IN terminals.  Press one channel, and motor goes one direction; press the other channel, motor goes the other.  DC power supply can be a commercial HO power pack of a full-wave bridge rectifier with an electrolytic capacitor across the output.

To prevent uncoupler magnet burnout,  is possible to rig a time delay relay in the feed that will open the circuit after a few seconds and remain open until the circuit is deenergized.