Tips and Tricks from MartyE .com


Phasing a Lionel PWC ZW Controller and 2 PW transformers!


This is my second attempt at an instructional page and would love to hear some comments back!  With that said let's get onto the project...


    To phase the transformers you will need...

  1. Two or more transformers

  2. At least a 16 gauge wire for each transformer

  3. An AC strip that will accommodate multiple transformers being plugged in

  4. A 18V light with leads or an AC Multi Meter

  5. Either a paint pen or colored nail polish, enamel paint or other marking device

  So what is phasing transformers and why would we need to do this?  Well simply put phasing transformers is making the AC outputs of the each transformer being in sync or on the same positive and negative going cycle at the same time.  If they were not then when a train leaving a block and entering a block controlled by the two non-phased transformers you will get a pretty good spark as well as a over current draw because the voltage between the 2 blocks or separately powered loops  could be fairly high depending on the transformer settings. It is also possible to damage some of today's modern electronics or circuit boards. It is effectively creating somewhat of a short circuit if a car would straddle the two out of phase blocks that would allow current flow either by way of the chassis or pickup rollers on opposite trucks.   Click here to see a rough example of transformer waveforms out of phase. 2 blocks with in phase transformers set at the same voltage will be seamless as the train moves from one to the other.  Click here to see a rough example of transformer waveforms in phase.  I used separate pages to get a better resolution.


You may want to check your wall outlet first for a proper setup. The reason I bring this up is because if the transformers would be plugged into 2 different outlets they must both be wired the same to work correctly and for safety purposes.  This can be done with a simple and inexpensive checker sold at most home improvement stores.  If the checker reads a problem contact a qualified licensed electrician.  Also and this is important!  If you are using more than 1 outlet that is on a different circuit, make sure that they are fed off the same phase coming into the house.  If they are not you can get out of phase results even with correct wiring when using 2 newer transformers with polarized plugs.  Most house service is made up of 2 phases and a neutral and it would make life a lot easier if all circuits originated off a one of the two hot lines.  Once again I stress that you should leave any wiring to a license electrician.

  Newer homes will have outlets with 3 prong receptacles with a wider neutral opening.  This wider opening will accommodate the wide prong on the PWC ZW Controller.  If your plugs do not have the 3 prong wider neutral you'll need an adapter.  I must stress here once again that there are local codes that must be followed and all home electrical question should be asked to a qualified licensed electrician.


The first thing I do when using the modern controllers such as the PWC ZW Controller is to mark the neutral prong of the plug with fingernail polish or other marking pens.  That would be the wider prong on the plug.  This plug can only go into the receptacle one way and should not be forced into it in the incorrect manner. Older transformers normally  do not have the larger prong.

  An example of a "polarized" and "non-polarized" plug.    
Note the bigger prong.    These prongs are the same!

This will be my reference for all other transformers.  Now take a peice of 16 gauge wire and connect one of the "U" terminals of the PWC ZW Controller to a "U" terminal on your PW ZW. This creates a common buss.

Now with the handles down or off plug in both transformers.  Connect you light bulb or meter across the "A" terminal of each transformer.  Bring both "A" handles up to about 10volts.

Setting each ZW for about 10 volts

 If the meter reads high, on my meter about 10v, or the bulbs glow bright your transformers are not in phase.


Note how bright the bulbs burn and the meter deflection.



  If the voltage reading is low, about 2v, or the bulb glows dim they are in phase. 

Note how dim the bulbs burn and the minimal deflection on the meter.

 If they are out of phase and the lights burn bright or the meter reading is high then the solution is very simple.  Take the plug from the old PW ZW which does not have a wider prong and simply turn it around in the outlet.  Recheck the bulb or meter and now the readings should be low or very little illumination. The little bit of reading on the meter or glow is due to the outputs not being perfectly set at the same level.  Pull the plug and take the fingernail polish or marker and mark the prong that was in the wider opening on the receptacle.  Sorry about the color, that's all my wife had.

This will now correspond to the wider prong on the new PWC ZW.

Follow the same procedure using the PWC ZW Controller and any other transformers.  There a few exceptions but most PW transformers with a common "U" buss will work.  When all the transformers are phased and plugged into the outlets the marking should all follow the same pattern.

All of the marked prongs are in the same receptacle position.

If you are phasing two postwar transformers only and they both have small prongs then choose one to be the reference and check and mark any other PW transformers to it.  If you do eventually get a newer transformer with a polarized plug you would then need to check all phasing to it as it will have to become the reference transformer because it's plug cannot be turned in the outlet.

Like I said earlier, keeping all the transformers phased is very important to avoid possible problems with new electronics and voltage issues.  Transformers that will be used to power accessories that will share the common of the layout will also need to be phase for proper operation.  These would include switches and  isolated rail track sections for triggering accessories.  This is a very simple issue that with a few minutes of your time can prevent frustration in the future!


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