ZW & Z-4000 question

Have both transformers,they both have super fast breaker protection. They should work in unison as long as you do not parallel them. If they run different power blocks on the same loop pay attention to rollers jumping the adjacent blocks. They may or may not phase,there is a 50-50 chance but since the plugs are polarized. if they are out with each other it may not be easy to phase them without either a internal rewire or cutting prongs on the polarized plugs or using different house outlets that are oppositely phased. Even if properly phased the sine waves may not transpose exactly since the bricks are pure sine wave and the Z4000 wave,although pure is made with solid state electronics.

Phasing is only and issue if the transformers are paralleled. Opposite phased transformers can share a common without issue.

The breakers protect the wire and transformer,not the train circuit board. To add protection install a TVS on each loop. The DCS system has one built in.

Dale H

Dale, While the PH is pure AC, it is modified by the ZW circuit board in the controller and the output is not pure sine wave.  That is why there are compatibiliy issues with  trains that need a pure sine wave.

Your phasing and parrallel comments seem confusing.  If you are going to share a common then transformers should be phased properly.  Otherwise, at some cross over that bridges center rail power a large voltage differential will exist.

Parralleling of transformers to feed a common load continuously is probably not recommended at all due to unregulated power supplies, and much higher fault currents, plus the potential for circulating currents.

You could wind up with a 18A short that is fed via 9A from each transformer never triggering a circuit breaker trip. 

Using a common ground and setting up blocks via insulated center rails is not really paralleled transformers operations; other than temporarily as a train cross from one section to the next block.  Hence the need to phase transformers.  G

"Dale, While the PH is pure AC, it is modified by the ZW circuit board in the controller and the output is not pure sine wave.  That is why there are compatibiliy issues with  trains that need a pure sine wave."

I assume he is just using the bricks,without the zw transformer controller. The bricks themselves are pure sine wave. If one transformer or controller puts out a chopped wave and the other brand transformer puts out a different type wave they are really never in phase completely as the sine waves will not line up exactly. They may be both positive ,then negative at the same time but potentials will always be a bit different during each cycle. The waves do not transpose exactly.

"Your phasing and parrallel comments seem confusing.  If you are going to share a common then transformers should be phased properly.  Otherwise, at some cross over that bridges center rail power a large voltage differential will exist."

The original post does not give details of how the layout is wired. If 2 transformers merely share a common the only time phasing is an issue is if somehow the 2 hots are connected as you describe. With careful wiring that can be avoided. The question was can they share a common? and the answer is yes as long as the 2 hots are not connected in any manner.

 "Parralleling of transformers to feed a common load continuously is probably not recommended at all due to unregulated power supplies, and much higher fault currents, plus the potential for circulating currents."

I do not recommend paralleling transformers. Lionel does it with 2 bricks putting out 20 amps and I ma not crazy about that idea. 10 amps is enough of a loop IMO.

"Using a common ground and setting up blocks via insulated center rails is not really paralleled transformers operations; other than temporarily as a train cross from one section to the next block.  Hence the need to phase transformers.  G"

Temporary or permanent you are paralleling the transformers via a 22 gauge wire between rollers of the engine and lighted cars.  Not good IMO. If in your house a circuit had a temporary overload condition the electrical system should be designed to handle it. But you should not wire things with the possibility of overloads just because they are temporary or happen only when the planets line up..  Likewise with your train wiring.  Roller jumping can be avoided with 2 relays and a transition block. If you are going to parallel 2 transformers temporarily then just parallel them them permanently with proper wiring and breakers rather than doing it with pickup rollers. Not a good arrangement but better than the choice you describe.

Dale H

GGG & Dale, thanks for you comments.  Let me be more specific,

I plan to use the bricks with the  modern ZW.  I would use Z-4000 for 2 loops that are connected via crossovers.  I was thinking of using the ZW with 1 brick for the loop that would sometimes run conventional and another brick (or 2?) for switches, accessories, etc.  Can I wire the common from one transformer to the other (or to the same buss bar)  to avoid running a separate common buss for the switch, accessory transformer?

Doug

Doug

I do not see a problem connecting commons again taking caution that the circuits can not be put in parallel with train wheels or rollers. On my new layout everything will use a common bus made with 2 loops of 12-2 Romex house wire giving a 120 amp capacity; lighting, track loops,DC relay power, accessories etc. The common bus must be large enough to carry the sum of all the amperage of all the transformers. I use bus bar extensions described here

www.jcstudiosinc.com/BlogShowT...=432&categoryId=

Because the layout is large,about 1700 sq feet,a common return bus saves considerable wiring and reduces voltage drop

Dale H

Doug,  I think it can be done.  I do have a Modern ZW with common grounds to a small accessory transformer, Power Master, and a K-Line 120W transformer.  The ZW/PM and K-line operate 3 loops that connect via cross over and insulated center rail.  They are phased and I don't have any arcing when crossing over, nor trouble on the lay out.

Use the instructions that come with the Lionel ZW to phase the two and run a small test.  I don't think it will be a problem, unless they can't be phased because of the polarized plugs.  G