Lionel ZW transformers

[dwiemer]

Here I am again to ask another question of this learned crowd.

I just "won" an auction for a Lionel ZW250 for $102.00.  I think it is a good win, as it looks to be in good shape.  Now for my question.  I believe I read here that the 250 and the 275 are basically the same animal as far as output.  Other than what the back of the transformer says, are their any other differences?  Are their any issues with these transformers that I should be aware of.  I already know to replace the power cord and check the rollers, etc.

Thanks,

Dennis

[ChiefEagles]

Great win.  I think it is the name plate in the middle that is an indicator.  Heavy duty guys.  I've got one and it will run 8 new diesels with TMCC with no problem.  I think the whistle rectifiers may need changing.  Mine had already been done with the newer style.  I now run my conventionals with the TPC and CAB1 and so that does not matter.  

[Anonymous]

Nice transformer, I also have the 250zw along with a prewar Z  I use for my conventional operations.For command I use 135 power brick. The 250ZW are tougher to find than a 275ZW imo......tony

[ben10ben]

The name plate on top is different. On the 250, it's just a simple round circle L, and on the top, it's larger and has writing around the outer edge of it.

I'm pretty sure that the 275 has an improved/more efficient core, which is what allowed them to up the rating from from 250 to 275.

[tranz4mr]

True. The core in the ZW 275 is more dense with fewer voids making it more efficient. This was achieved by creating a 2 piece core with each piece made of many layers riveted together. The 2 pieces were than glued and press fit together. In the ZW 250 the core is made of alternating C-Shaped metal plates placed on top of each other creating voids at each end between each layer.

[Birds]

Sounds like a nice find.

According to the documentation found in the on-line library at Olsen's Toy Trains website, the ZW has a useable output wattage of 180 watts.  No mention is made of a difference in useable output wattage between the original 250 watt and subsequent 275 watt versions.  There is only reference to changes such as rivited lamination stacks, pilot light voltages, etc. over the years.  I have not been successful in finding anything stating that these changes increased the useable output wattage.

Enjoy,
Birds

[dwiemer]

Birds,

     That is along the lines of what I recall.  I think that the advantage of the 275 comes in for sustained use, like running at high watts for a long period of time.  I doubt that I will have problems of running trains for a typical operating session.

     Thanks for the replies.  Once I get the transformer in, I will rework her and by then, I hope to have some progress on the layout.  I think between the ZW,  KW and 1033 that I have, I should have my transformer needs met for the forseeable future.  I also have several CW80s that I can use for Christmas layouts or anchors.

Dennis

[tranz4mr]

Strange but true. I checked Greenbergs and KLines repair manuals and 3 other sources and the ZW 250 uses up to 250 watts and puts out up to 180 watts total, the ZW 275 uses up to 275 Watts yet no mention of its output. There is no mention in any of the manuals or books on the output of a ZW 275 or ZW 275R. Has anyone ever tested this? Is it written somewhere?

[CHOO-CHOO MIKE]

tranz4mr

   Can't you test it out on one of your 10 zw's.

 I believe I saw it somewhere that the 275watt model puts out about 180 watts.

We should send this one to Myth Busters.

[tranz4mr]

Actually it's only 5 and hopefully I can rebuild and unload 2 at your table at the show next weekend in Denver
http://www.rmdtoytrains.org/2006%20Summer%20Meet%20flyer.htm
Maybe I can borrow a giant power resister from  work tomorrow as well as a ammeter
and "Myth Bust".

[CHOO-CHOO MIKE]

  I've got an ampmeter.

I will not have a sales table in Denver. Selling trains in August is like trying to sell sand at the beach.

However I will be operating with the High Plains 3 Railers.

[dlagrua]

Great win.  I think it is the name plate in the middle that is an indicator.  Heavy duty guys.  I've got one and it will run 8 new diesels with TMCC with no problem.  I think the whistle rectifiers may need changing.  Mine had already been done with the newer style.  I now run my conventionals with the TPC and CAB1 and so that does not matter.  

 

Don't want to get off topic but I am curious how you acheive TMCC control with the old ZW's. I would imaging going to a solid state rectifier will get the horns and whistles on these newer locos working but you'd still have to add the TMCC transmitter modules and I am uncertain of the compatibility..

[tranz4mr]

I did a few tests on 2 ZW 250's and a ZW 275. All are rebuilt with new rollers, cords diodes etc. I hooked up 6 large 250 Watt 5.5 ohm resisters in parallel plus an ampmeter and a voltmeter. Brought up the throttle until just before the breaker tripped.
Repeated with different settings until the breaker would not trip. The ZW 275 ran at about 178 watts as expected and remained very cool into about 1.2 ohms. The ZW 250's ran at up to 240 watts into 1.2 ohms and never tripped even at full throttle but ran significantly hotter than the ZW 275. When run into .7 ohms the ZW 250 would run at 160 watts without tripping. Now this was far from a scientific test but it seems like the ZW 250 is a pretty good deal since they are generally priced well under the ZW 275. The ZW 275 did run cooler and the circuit breaker seemed to trip at about the correct power level.

[dwiemer]

Kent,

     Thanks for the research and sharing your information.  From this, I think I did pretty good with the 250, but I will certainly have a separate circuit breaker even though I do not run any command control.  I also have a KW, that I will put a circuit breaker on too.  It looks like I should have plenty of power to run my layout.

thanks for all the responses.
Dennis

[lionelsoni]

Dennis, as long as you're adding circuit breakers, I would suggest adding a separate one for each output.  This will provide the protection which the Lionel design lacks against damage from connecting the outputs together.

See the note at the bottom of this KW diagram:  http://pictures.olsenstoy.com/cd/transfmr/pskw2.pdf

[dwiemer]

Bob, thanks for the suggestion, I will do it.  What amps would you suggest for these breakers?  Again, I am not running command control, but do have some newer engines.

Thanks,

Dennis

[lionelsoni]

Use 15 amperes for the ZW and 10 for the KW.  (Or less, if you want, of course.)