ZW Transformers

The ZW is the undisputed king of Lionel’s transformer line. It was designed to operate 4 trains simultaneously from 4 speed controls mounted on the side of the unit.

The Lionel ZW 250/275 is still the widest used model train transformer ever built, even knowing it’s design is approaching 100 years old, People still really like them.  So what makes these original transformers so great when compared to what is available with solid state parts available today? The answer is simple. The method that Lionel came up with to control the speed of the trains.  Here briefly is what they did.

The internal transformer was engineered and built with exposed heavy duty copper windings. These windings were coated with varnish, on their sides, so they would not short each other out. The tops of the windings did not have the varnish. So what they did was design a very simple lever that had a carbon roller that would provide contact with the exposed coils. The levers (4) are attached to the 4 controls on the outside of the case. The effect was a very stable method of controlling the output voltage to the center rails of the track. Then they added an interrupter circuit to control reversing the engines, and a dc pulse circuit using a single rectifier to activate the whistles in the engines. Absolutely incredible considering the time this was engineered.

Since then, every manufacturer including Lionel has attempted to come up with a new design using modern solid-state parts to replace the original roller over the copper windings technique. Why? The original design is way to expensive to try to build today.  So far, many of their designs were prone to early failures. Why? Because they use (often unprotected) of solid-state parts to control the output power.  These components do not like AC. Our engines even today for O gauge still run on AC.

We at TinMan recognize that the original design is still the best way to control engine speeds. Our objective is simple. Keep the original design and make improvements in other areas and upgrade the original design. Specifically, here is what we do when we recondition these units.

·         Change the rollers (unless they are like new) with an improved copper improved design

  •  Eliminate the original rectifier and replace with a modern bridge unit that will enable the transformer to operate the bell circuits found in newer engines.
  •  Replace the original slow acting circuit breaker with a modern fast acting model. Why? The original circuit breaker was designed to protect the transformer from burning up. The internal transformer being very heavy duty will take a lot of short circuits without damage. So all that was needed was a very strong circuit breaker (over 15 amps.) and it takes a long time to open. This design does very little to protect the trains etc. So we install a modern breaker which opens much faster in order to protect the trains etc. as well as the transformer.
  •  Change the power cord with a 3-prong plug, to make phasing easier, and ground the exposed metal plate on the base. Why? Because the internal transformer is resting on 2 metal plates that are bolted to the outside metal base. While we have never had an issue with a problem with the internal transformer, it is possible and as a result send high voltage to the exposed metal plate. Grounding this plate will stop this very remote possibility and makes phasing with other transformers a breeze.
  •  Clean the exposed copper windings.
  • Add switches to the front of the transformer to select the whistle control to operate both whistles and bells.
  •  Add an additional output power terminal on the back of the transformer which gives a constant 20v. Why? The transformer has two variable controls for accessories or to control speeds on trollies, bumper cars etc. Plus, other toys like the milk cars do not like wide open voltages. Switches, lights, RCS tracks etc work best with a higher voltage which is now available. In the pictures you can see the additional power output terminal to the left of the U terminals and the A to D terminals.
  • Preform a final check for proper outputs with not just voltages, but also under 3 and 6 amp loads. This is done on a “transformer report card” that is included with your transformer

 The px below shows the location of the extra terminal which we install to the far left. This termina gives you the constant 20 volts


Now to our latest innovation

There is some talk in the O gauge community that despite modern circuit breakers, this is still not fast enough. With many of the new engines, that have significant electronics installed for some of their new great toys, can be damaged due to slow acting circuit breakers. Since we began changing the old breakers with the newer designed ones, we have not had one complaint about engines etc being damaged due to short circuits. That is not to say that it never happened, just that we have heard of any.

In the community there are suggestions that an additional fuse should be used in line with the train power that will blow almost instantly when it senses a short.

So, what we are now doing is installing, as an option, is install built in fuse holders on the back of the transformers. We are also supplying extra fuses with the option. These fuses only protect the A and D power outputs which are mostly used for trains.

AS discussed the px below  shows where the optional fuse holders are installed

So, the question: Should you purchase this additional cost item for your transformer?  If you have some modern engines that have those new toys, might be a good idea. If you do not have any of those and do not plan on getting them, no, it is a waste of money. Also having a really fast power shut down can be a nuisance. It requires very little short circuit to blow the fuse, way less than ½ the time of the breaker, which could be a pain.

As with all our transformers, included are full instructions and a no BS 2-year warranty.

Sorry for the lengthy discussion, but we take our work very seriously and are quite proud of what we do. So yeh a little bragging rites seemed in order. As discussed the px below shows where the optional fuse holders are installed.