Greetings all!! I have expanded my layout to include a 110ft main line with 6 sidings and am wondering if I can use more than 1 Lionel CW-80 transformer in series. I’ve accumulated 4 of them from sets, and hate to ebay them and dump more $$ into a ZW, but I’ve ready mixed reviews on using more than 1 on the same layout. I run all TMCC or Legacy engines. When I have no engines running, the layout tests at 15.5V all over. Regards, Dan
Yes you can, especially if you are running TMCC or Legacy since you will have them at full power for train running. I run a ZW and two CW80s on my layout. The ZW runs the trains and the CW80s all the accessories. Had I known what I know now, I might have got the ZW, but hey, I get my use out the the CW80s that I have.
You are measuring only 15.5 volts on your layout because you are using the wrong kind of voltmeter for the waveform that the CW-80 puts out. Voltage is ordinarily measured in root-mean-square (RMS) volts, that is the square-root of the average of the square of the instantaneous voltage. You can get a meters that does that, usually described as a “true RMS” meter. But most meters instead measure the average of the absolute value of the instantaneous voltage, which is a lot cheaper to do. If you assume that the voltage waveform is a sinewave, then the average that the meter measures is proportional to the RMS voltage, and is about 90 percent of it. The meter is calibrated to indicate the RMS voltage corresponding to the average that it actually measures.
Knowing how the CW-80 generates its voltage waveform, I can calculate from your 15.5-volt measurement that the true RMS voltage is 18 volts, just as the CW-80’s specification says. I believe that this is the voltage that TMCC is intended to be used with.
The fact that you read the same voltage everywhere on your layout doesn’t tell us anything about the voltage that the trains are getting, unless you are making those measurements at various places on the track as a train passes.
I can think of two reasons why you would want to wire two CW-80s in series:
o You are running locomotives that need more than 18 volts, like the 773 or many pre-war locomotives. If were the case, go ahead; but be careful, because your voltage could get as high as 36 volts with both transformers turned all the way up. But you say that you have only modern locomotives.
o Your trains are slowing down somewhere on the layout. A better fix for this is to improve the track joints or to add adequate feeder wires, no smaller than 14 AWG.
Thanks for all responses, and for the technical explanation Bob. I’m sure you’re right about my 30 yr old Fluke meter. I’m running all Fastrack, and have the CW-80 connected to my original 6x9 layout in 4 places. The rest of the layout is still feeding off of that run of track, which is only about 1/5-1/4 of the total track. I have created a 14AWG buss for the new sections, and should probably reserve judgement on the performance until I get that connected. The remaining sections are built from 36" Luan doors, and there are 4 track leads every 80", so that may do the trick.
I have three set-transformers running on a Fast Track layout. One MTH Z-1000 supplying the bulk of the layout, and a CW-80/CW-40 pair hooked in series supplying an uphill grade. In this way, when running conventional Locomotives, I am able to kick up the power to the uphill section (my meter reads 15 volts as well!) while running at a more leisurely pace on the flat sections. But with your discussion of wave form, am I doing something wrong? I believe the MTH and Lionel transformers put out different wave form power. Is this a problem?
Why are you running your transformers in series? You can get that much voltage from one transformer.
Connecting transformer outputs together in parallel, as happens whenever your train passes from Z-1000 to CW-80 territory or back, is not a good idea. Unless the transformers’ instantaneous output is identical, one may try to feed the other. Connecting CW-80s together in parallel is not unsafe, since they are both switching the same voltage from the actual transformer that is located inside the CW-80 “transformer”. I don’t know what’s inside the Z-1000.
Bob - any comments on ‘phasing’ the CW-80’s? Assume that adjacent blocks of track are powered by separate CW-80’s. I know that with conventional transformers, this is not a good practice, as it can lead to large internal currents in and possible damage to the transformers, not to mention the electronics in the modern locomotives, as the train runs from one block to the next.
I described the set up as in series - it’s in parallel. Also, the transformers are in separate blocks with the hot isolated from each other. My question is based on tying together a CW40 and a CW80 in parallel. Is there any real benefit?