O27 Track Block

[lionelsoni]

What Tony says about polarizing the transformers seems to assume that you are going to run trains from a block powered by one transformer to an adjacent block powered by the other transformer, which is something that some folks to. This operation is not without its risks, however, since the two transformers must be set to very nearly the same voltage during the transition. To the extent that they are different, a fault current will flow between them, through the train pickups, much like the fault current that flows through a short circuit. This may be brief enough not to damage the transformers nor the wiring; but there will be arcing at the pickups. If you don't intend to operate this way, it matters little whether the transformer plugs are coordinated.

By the way, operating with rheostats instead of variable transformers, in the early prewar manner, eliminates this problem. This is one of several considerations that have me mulling whether to change over to rheostat operation.

[Anonymous]

It helps if you think of electricity in wires as water flowing through pipes, and each transformer as a separate faucet and drain. Another thing that's important to know is that with AC current, there is no positive & negative, there are hot & neutral. The neutral post on an AC transformer is usually marked "U," but not always. The hot post is usually marked "A," but on the ZW, for example, there are A, B, C & D posts, each corresponding to a different throttle. On the postwar 1044 (which is what I have), the neutral post is A & the hot post is U. Go figure.

Block wiring is pretty simple, if you follow these rules:

1. You separate one block from another by putting an insulating pin in the middle rail where the track sections of the different blocks meet. If a loop only has 2 blocks, you need 2 insulators, etc.

2. Make one outside rail "common" and connect it to the neutral posts on both of your transformers. This is like connecting both drains together & having all the water flowing through one pipe. You always use conducting steel pins to join track sections together on this rail.

3. You control which transformer is connected to which block using "single pole double throw center off" toggle switches (known as SPDT center off in electronics catalogs). You wire the hot post from each transformer to the one of the outside posts of the switch. You then connect the middle post of the switch to the middle rail of the track. When the switch in in the middle position, both blocks are off. When you throw it one way, one transformer is connected to the block, and the other transformer gets connected when you throw it the other way.

4. If you have older postwar transformers that don't have polarized plugs, you have to polarize the transformers. To do this, connect the neutral posts of both transformers together, then connect a wire to the hot post on only one transformer. Plug them both in, then turn them both to about 1/2 full. Touch the hot wire to the hot post of the other transformer momentarily. If you get a large spark, you need to unplug one of the transformers & turn the plug around. Repeat the touch. If you get little or no spark the second (or the first) time, they're OK. What you should do is mark one prong on both plugs so you'll know which way the plugs have to go into the socket to keep them poliarized.

I hope this makes sense & helps.

Tony

[Anonymous]

What exactly is the layout your making. If you could tell me what your setup is exactly is, I could make a diagram for you.

[spankybird]

Hi jwalk

Check this thread
http://www.trains.com/community/forum/topic.asp?TOPIC_ID=18596
one of our forum members “Jerrylovetrains” did a great pic on it. Hope this helps


tom

[Anonymous]

Where can I find detailed instructions for setting up blocks for running 2 trains?