Conventional Wiring Question

[BobbyDing]

Lionelsoni,
I have purchased some switches and may be taking your advice in the near future. Rite now 3 loops, 3 transformers. Smooth as silk.

Bobby

[BobbyDing]

Oh Yeah, No relation to Bill Ding, Though there is a resemblance to my mother in law! hah!

[BobbyDing]

I had to wait for the weekend before I had any time to continue this. So today I finally got around to going thru my transormers (1033's) and found that one out of the three was wired backwards (with reference to the others). I replaced the power cords on all three with three prong cords (the originals were all cracked anyway) so that none can be plugged in reverse of the others. I also did the diode upgrades for the whistle control on all three 1033's. The whistle functions had stopped working on two of them. Now when I tie all the "A" connections together, each "U" is ~17 Volts at full throttle, and no more than 1.5 Volts between any of the "U"'s (voltmeter going from U to U). All three will now trigger the whistle again too. Which is nice.

You folks were a great help. Thanks...Bobby

[Anonymous]

Bobby Ding

Are you related to Bill?

Charlie

http://audiokarma.org/forums/image.php?u=4903&dateline=1114528079

[lionelsoni]

Isolating all the rails is not necessary; but it is not harmful.

The usual common terminal, connected to the outside rails, for a 1033 is A (or B if you want a lower voltage range), not U. U is the common for the Lionel multiple-output transformers (like the Z and ZW). I don't know why they did it this way. If you're not using any accessories, it doesn't matter, however.

The arcing is due to a voltage difference between the transformers. If they are out of phase, there will be a greater voltage difference than if they are in phase. You have a safer situation than if you had a multiple-output transformer, since your transformers and wiring are protected by the transformers' circuit breakers from the fault current that is causing the arcing.

A better way to do what you're doing is to switch the blocks between or among transformers. That way you can keep a train on the same transformer as it moves anywhere on the layout. To do this, first do connect the outside rails together and to the A terminals of all the transformers. Then get a single-pole switch for each block and connect the switch's common to the center rail of the block. Then connect each other terminal to the U terminal of one of the transformers. The switch then selects which transformer is to power that block.

The trouble with having three transformers is that the simplest switch, a single-pole-double-throw (SPDT), will only accommodate two transformers. However, you can use two of these per block to handle three. The center-off switches are best for this, because you can shut off a block entirely. With an SPDT and a DPDT per block, you can reach four transformers. With an SPDT and two 3PDTs (harder to find), you can do eight.

However, you may find that, with the switches, you don't need three transformers, if you don't run three trains at a time. You may also decide that it is useful to subdivide your loops into smaller blocks, so that two trains on different parts of one loop can be controlled separately, as when swapping trains between loops. This doesn't require any more transformers, of course, just more switches.

[Anonymous]

1033's don't have polarized plugs. Are you sure the three transformers are actually in phase? Internal wiring of the cores may be reversed on one of the units. Use a voltmeter (set to low voltage AC) to check that they really are in phase (get readings from hot to return on each loop by first setting track voltages to match as close as possible) THEN test hot to hot, it should be near zero if the units are in phase and approximately double if they are not.

You may see some arcing if the voltage levels between the blocks are different when a loco or illuminated car crosses the block as there will be some reverse current flow from the block with higher voltage to the block with lower voltage.

[willpick]

First, Welcome! Next: what to do to fix your sparking. 1) The outside rails should not be isolated between loops. The center rail must be, so that's OK. 2) Even though you are using the same 120VAC phase to power the transformers, they still may be out of phase. Best way to check this is to connect the U posts to each other, then turn the voltage up to about halfway on each transformer. Measure the voltage from the output post of #1 to the output post of #2. you should have a small voltage difference(less than 3-4 volts ac.) IF you have a large differential(10-12V or more), you need to reverse the AC plug for transformer #2. This should put #2 in phase with #1. Repeat for transformer #3. Don't remove the common connection between the transformers, they should always be connected together.
There have been several threads about phasing transformers, if my instructions are not enough(or are not correct[:)]). I suggest that you do a search for phasing transformers if you want more information(or need more help)

[BobbyDing]

Hey Folks,
I'm about to wire a conventional layout and need some advice. I can dance my way around a computer with ease, and have worked a lot with TTL (low voltage DC) electronics. But my A/C knowledge has always been very weak.

What I have is 3 loops that are physically connected via switch tracks, but electrically isolated via those plastic track insulators (Altas 21st Century 3 rail). I installed 3 insulators at each spot, so that all 3 track rails are isolated.

I also have 3 1033 xformers that I'm using to power, each loop with. The "U" is connected to the outer rails on all. When running a loco from one loop to the other, large sparks would occure as the two xformers were suddenly shorted via thru the crossing loco. The loco goes thru without stopping, but the track gets nasty arcing marks on it. The arcs occur on both inner and outer rails. I'm thinking now that this may not have been the best of plans.

All the xformers are on the same phase of 120. Can/should the "U" poles be connected between the xformers? Or should I abandon this plan?

Thanks for any ideas.

Bobby