My new legacy SD90MAC runs fine with my '60s era KW in conventional mode. The KW doesn't put out any power until about 6 volts, which might make some of the newer engines jump a bit at startup.

I went with the Legacy remote because I wanted to tap into the more advanced functions available in the engine. But I understand completely if you want to stay conventional.

 

For conventional operators, hard to go wrong with something like a refurbished ZW. A couple of other good choices are the MRC Pure Power Dual or the MTH Z-4000.

 

Yup, a ZW is a horse at 275 watts. KWs are 190 watts. Pick whatever you need to power your layout.

 

Seems like this question comes up quite often. I recommend Lionel's ZW-L. I know it's expensive, but in the long run well worth it. My smaller layout is probably over-powered with a ZW-L, but I've never found a transformer I like better.

Over the years, I've had an older ZW, a couple of CW80s, and an MTH Z-4000. I liked them all but nothing beats the ZW-L

I've also found that the newer Lionel engines, either conventional or Legacy, respond better to the ZW-L's chopped sign wave, than to the Z-4000's smooth sign wave.

 

The ZW-L is certainly an attractive option. The Z-4000 is in my current price range. I may put off buying a ZW and let it become a Christmas present. I don't have a layout yet, I have been testing locos with my older KW. It works but I can do better I guess.

Thanks for the input, thus far. I would still like to hear opinions about choices out there. Everyone has been extremely helpful!

Tom

 

What do you mean when you say the newer stuff is finicky when you use the KW? At 190 watts, I would think it has enough power for a few trains. I use two ZWs but I sometimes run as many as eight trains at a time (with DCS). When using any post war transformer, make sure to install a fast circuit breaker or fuse between the transformer and track to protect modern engines.

 

The ZW-L is a great transformer, but it's also WAY more expensive than all the other options.

 

My dad and I both use Z-4000 transformers. They work great. I love that they use modern electronics in their operation.

 

Of course I ordered a Z-4000 and then found a old ZW in a hobby shop for $100. I bought it. It works fine and just needs a little cleaning. I used some car wax on the top and it cleaned up nicely.

So, I will end up with both. The old ZW it definitely a good product. No idea how old it is though...

Tom

 

Make sure to use modern fast circuit breakers as you could fry the locomotive electronics in a derailment when the rails are shorted out when using a vintage transformer.

 

I would get a 5 amp breaker something like this.

https://www.digikey.com/product-det...uct-detail/en/sensata-technologies-airpax/PP11-2-5.00A-XX-V/723-1267-ND/2781056

Another option is to use 10 amp automotive in-line mini fuses.

It’s also a good idea to install a TVS diode at each power connection to the track.

https://www.digikey.com/product-det...shay-semiconductor-diodes-division/1.5KE36A-E3-54/1.5KE36A-E3-54GICT-ND/2407434

 

Ok, thanks for the links. I understand the circuit breaker/ fuse set up but what would the TVS diode be for?

Thanks again.

Tom

 

TVS prevents electronics destroying voltage spikes. Gotta be bi-directional for AC current. I use these:

https://www.digikey.com/product-detail/en/1.5KE36CA/1.5KE36CALFCT-ND/1530580

Pete

 

TVS stands for transient voltage suppression. They are installed between the AC and common connections.

 

Okay. I am in no way an electronics guy, so this helps! Thanks.

Here are my two transformers...

 

Thanks Pete.

To illustrate, there are two wires from the transformer to the track. One is the common and the other is power for a certain throttle.

Which wire would the Fuse/breaker and TVS be in line with?

Tom

 

The TVS is not in line, but across the power and return lines.

The fuse/breaker should be inserted in line with the power feed.

As to the value of the TVS I blindly followed the recommendations of GRJohn and Lionelsoni, they know so much more than I.

Pete

 

Very good. I had no clue as to the arrangement of the TVS. Thanks for the illustration!

Tom

 

depends on how much you want to spend. the American flyer 4B is 10 bucks and works better than any 100 watt transformer i have tried. they are cheap, powerful and stay cool. you have to replace the cord on them but that makes them cheap. for a basic powerful no frills transformer you CANNOT beat the 4B...

 

Interesting. The AF 4Bs are certainly plentiful on eBay. I may give one a try. There seems to be plastic cased and metal cased ones. Any difference?

Tom

 

i have only used the blue metal cased 4B, they are quite simple, have an effective instant built in circuit breaker and work better than the marx 100 watt transformer at a third of the cost. the 4B beats the Lionel 90 watt transformer hands down. i now have 4 of them, none of them was more than 10 bucks on ebay. these are really overlooked in my opinion, for the price and power available you cant beat the 4B transformer...

 

If the new locomotives seem finicky you definitely need to clean the transformer internals and posts, and you may need to replace the rollers and do a few more tweaks. I've run PS2 and a legacy locomotive off a RW I cleaned and did some work on, and on an old refurbished Z with no issues.

The other 2 things to look at are track connections, and wheel / cleanliness.

Using lockons on track that is oxidized w/o cleaning the contact surfaces is an issue. Also, dirty pins are another part of the track connections to check.

 

I built an inside out reverse loop out of old O-27 track. Total length was 45 ft. I wire brushed all the pins, top and bottom and snugged up the rail ends. I had only one connection to the track - abiet near the crossing which connects power to all four connection. I didn't have any issues with track voltage. Great power all the way around.

 

An AC transformer (e.x., ZW) can put out a maximum of 21 V AC. That is an "rms" rating for AC voltage. The AC peak voltage is 1.414 times the rms voltage rating. So the ZW's 21 V max output translates to ~ 29.7 volts peak. An engine with a heavy load may cause the operator to turn up the transformer voltage to attain the desired train speed. But AC transformers have internal resistance. Under heavy load that resistance causes voltage losses inside the transformer's windings (i.e., before the voltage gets to binding posts). So your not likely to hit the maximum theoretical peak, rather, a few volts less. Of course, operations can affect that. For example, powering the loco up a grade may require a high voltage. When the consist is on the downward side, some of that heavy load is removed (gravity). The train speeds up and the voltage will rise due to the lower load.

All of this could be measured during operations. In the absences of that, go with Quietman's TVS recommendations.

 

I've been recommending and using the 1500W 33.3V TVS at Digikey for years, they've always worked well for me. If you look at Mike's post, you'll see why the voltage rating doesn't make much sense to the electrically challenged. In addition, the spike protection we're looking for is way beyond the clamping voltage for the TVS, a collapsing coil field can generate voltages in the hundreds of volts, that's what we're trying to stomp on. Think of the ancient Kettering ignition that we used for ages, and is till after a fashion used in today's cars. The voltage generated by a collapsing magnetic field in a coil can generate a lot of voltage.

 

TVS is a Zener diode which is inexpensive spike protection. Attached is info on using TVS Zener diodes.

 

I love my ZW. It has a start voltage at about 2 volts. I can run my trains really slow with it.
The original circuit breaker in a ZW took 10 seconds to blow. A modern breaker will blow
in 2 seconds.

 

If it starts at 2V, it's been modified. The standard PW-ZW starts up at around 5V.

 

Perhaps MoPac's "starts at 2 V" was with a load.

That begs a question: Does the roller positioned early in the secondary winding translate to higher output impedance to the track?

 

I do know my ZW was serviced at Charles Ro. I do not know what they do to them. The circuit breaker has been changed. The service was before I bought it. I have a couple
American Flyer transformers and they start at 7 volts. No slow running there.