I know this has been covered before but could someone post a simple explanation for the statement I read in another thread stating "It all has to do with the modern engines running/smoking better with the chopped sine signal provided by the newer Lionel transformers".
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Lionel (Mike Reagan) has done some videos on the subject, here is one right from the 'horse's mouth' so to speak.
I think there also may be more related videos on Lionel's site, where this one is located.
Lionel (Mike Reagan) has done some videos on the subject, here is one right from the 'horse's mouth' so to speak.
I think there also may be more related videos on Lionel's site, where this one is located.
He sets the voltage to 15 vrms for both transformers so the peak voltage from the chopped sine transformer is higher than for the smooth sine wave output from the post war transformer.
However...if let's say they were both set to 18 vrms which is the max output from the chopped sine wave transformer, then the peak would be the same for both transformers and there would be no difference in performance.
Setting the voltage lower than max on the chopped sine wave transformer is sort of a contrivance to prove a point. But it's a valid point if that is how you run it.
Sales gimmick...
Sales gimmick...
Not hardly. A chopped sine wave (or chopped DC on HO and N) means only high voltages - usually 18 V, is sent to the track, which means the power bridges dirty contacts and track better, etc. Power is varied by the duty cycle (amount of the sine wave or DC that is actually sent), and the high voltage all the time and limitation on power via duty-cycle variation means you get a bit more linear response from motors, and much better low speed performance - at least I do. It all makes a very noticeable difference with the ZW-L and a less noticeable but perceptible difference with just a CW-80. I have some old AC pure sine wave units and they are in the closet and I tested them back to back and it really is quite better - the sine-wave units are in the clowset now, and I use only the ZW-L for trains and the CW-L for some of my 'Streets stuff.
Here is a figure illustrating what Lee and the Lionel guy are saying. You can see how the chopped sine has a higher peak voltage compared to the "equivalent" full sine wave from the older version transformers.
Yes...but if you are using the chopped and smooth sine transformers at full voltage, then in that case, there is no difference. Because, the chopped is not very chopped anymore. It's almost a full sine. In legacy use I would have both of them at full.
And...if you are running conventional and at lower than full voltage (likely), then the chopped has a higher peak and is better for the way the electronics is designed now.
This thread is reminding me of the media where only the data to prove a point is mentioned, and the rest of the data and how many or most of us use these transformers, is left out.
I have heard that old postwar locos may not like the new chopped sine wave and/or be damaged by long use of it to run them. I have also been told that this is not true. Anyone care to weigh in on the issue? I traded my old TW for a new 180 watt Lionel recently so the matter is of some importance to me.
I have only command control stuff, no conventional. Guess I will never notice a thing. I was thinking this was brought up (no change with command control voltages) when these videos came out, but couldn't remember for sure.
I have heard that old postwar locos may not like the new chopped sine wave and/or be damaged by long use of it to run them. I have also been told that this is not true. Anyone care to weigh in on the issue? I traded my old TW for a new 180 watt Lionel recently so the matter is of some importance to me.
Its true that the motors will see a higher peak voltage to run at the same speed as a lower continuous sign wave but the chopped sign wave methodology cuts the time that the motor is energized by 50% giving the motor giving it plenty of time to cool between cycles. I do not see this as harmful.
Here's my two cents. I'm certainly no expert and my test had to be as crude as could be but here's what I did.
Day 1: Subject Lionel TMCC Dash 8. Ran it 15 minutes with postwar ZW. Ran fine, smoke was OK. Switched to CW-80 and immediately noticed an improvement in the smoke output and thought the loco was a little smoother.
OK I thought, did the 15 minutes on the ZW really warm up the Dash 8 and make it smoke better for the CW-80? Well the only way to tell was to reverse my test the next day.
Day 2: Same subject, only this time the CW-80 went first. Smoke output appeared the same as the previous day after a 15 minute run. Then switched to the ZW and saw the smoke output drop.
Like I said, I'm no expert but just my findings. And I might add, enough to make me think about dumping my PW ZW for a new ZW.
We're you running the CW80 at max voltage? If the CW80 were at max and the post war xformer at the same voltage, then your results are interesting and a little unexpected. But a good result the way you use it is the best test.
As for running the AC motors with chopped sine waves, the only issue I know offhand is that the speed versus chopped sine control is not linear. The speed change would start out slow, get fast, and then go slow until the ac motor loses too much torque and then stall. Probably at about 2/3 down of the sine phase change from full on.
Same here with prewar Flyer.
Does the Z-4000 have a chopped wave output? 
Will it run Legacy equipped locos optimally?
Does the Z-4000 have a chopped wave output?
A: I don't know myself because I never looked at the waveform with a 'scope, etc. I have been told it has a type of chopping/high-frequency.
Will it run Legacy equipped locos optimally?
A: It depends on what you mean by optimally, and how important the difference is to you. I run conventionally only. I had a Z4000 before the ZW-L came out. It ran Legacy locos very wel, as well as everything else I had well, too. I never had any complaints. But when I installed a ZW-L, I noticed it runs Legacy and PS2 and PS3 locos just a bit slower, smoother, than the Z4000 did. It is a noticeable difference - maybe 5 - 7 mph slower while still being smooth, but whether it is worth the cost is something you have to determine.
Note that a few very old, pre- and post-war AC open-frame type motors don't like chopped power, at least like the ZW-L produces, as well as sine waves. I don't think the power damages them or anything, just just a really noisy and tend to jackrabbit when they start and not respond to the throttle linearly.
We're you running the CW80 at max voltage? If the CW80 were at max and the post war xformer at the same voltage, then your results are interesting and a little unexpected. But a good result the way you use it is the best test.
Let me first say electronics are my weakness... With the old ZW or the CW-80 neither allow full throttle without the loco going flying! In both cases the loco was run the "old fashioned" way purely off the handles.
Note that a few very old, pre- and post-war AC open-frame type motors don't like chopped power, at least like the ZW-L produces, as well as sine waves. I don't think the power damages them or anything, just just a really noisy and tend to jackrabbit when they start and not respond to the throttle linearly.
I can honestly say that I'm still so very confused 
. Sixty-six years of running my prewar tinplate using three Lionel Z Type. Not once did I hear one complaint or experience one "hot" choo-choo. I'll just go back to my corner and mumble to myself.
God Bless,
"Pappy"
Here is a figure illustrating what Lee and the Lionel guy are saying. You can see how the chopped sine has a higher peak voltage compared to the "equivalent" full sine wave from the older version transformers.
You have artificially lowered the voltage on the pure sine wave transformer. This is not a fair comparison, except at lower voltage operation.
The point being in command operation transformer voltage is set to Max and the chopped sine wave transformer now looks like the sine wave for equally rated transformers.
The electronics in the engine also matter. For MTH the Pure AC is rectified and boosted with caps so that you have about 22VDC as your starting voltage available. The circuit than deals with pulsed DC.
Isn't the newest Legacy also a DC based board now, taking AC in and converting to DC and using DC ground (No longer Track AC Ground as a reference)?
I have been running a ZW-L since I built my layout a decade or more ago, I can't say I see a difference in my conventional engine. The seat of the pants HP gains usually don't get reflected against the dyno.
G
Pappy - What if I just sum it up as the newer products run smoother/better off the newer transformers.
Have a great day!
Does the Z-4000 have a chopped wave output?
Will it run Legacy equipped locos optimally?
As I understand it, the Z-4000 has a "smooth" sine wave output. The sine wave voltage is electronically determined based on the throttle positions and the sine wave is constructed from a series of narrow pulses. In effect, it's a smooth sine wave and does not have the chopped sine peak that would be beneficial at part throttle compared to a smooth sine transformer.
If I'm using a postwar ZW, but running it through a power master or TPC300 (in command mode), does that produce a chopped sine wave?
Does the Z-4000 have a chopped wave output?
Will it run Legacy equipped locos optimally?
The Z4000 has a synthesized sine wave, it isn't chopped like the CW-80.
See MTH Z4000 Waveform Pic, I did some captures of output at various loads and voltages.
I have been running a ZW-L since I built my layout a decade or more ago, I can't say I see a difference in my conventional engine. The seat of the pants HP gains usually don't get reflected against the dyno. G
Since the ZW-L has only been around for about a year, that's a pretty neat trick! Where did you get one a decade ago? 
If I'm using a postwar ZW, but running it through a power master or TPC300 (in command mode), does that produce a chopped sine wave?
Yes.
Hence my recommendation in the other post.
I went over to the ZW-L from a Z-4000 and there is an appreciable difference in terms of the smoke performance of most Legacy engines I have. It's not every engine that shows a difference but all of them bar a couple of stubborn underachievers.
I've been told by a third party manufacturer that the Z-4000 is not friendly to the non-MTH smoke units they use. Exactly why that would be so I don't know for sure but I can also see an improvement from using the ZW-L with these engines. It runs my MTH engines fine, at least to all outward appearances.
Sounds that maybe my smooth sine wave transformers (Z4K, MRC) are beneficial for me in fine-tuning smoke output. I run Legacy, PS2, TMCC, PS1, and conventional, in about that order of preference. I have a lot of engines and seems smoke units aren't created equal! Sometimes "Low" isn't enough; and "Medium" is too big of a variance. I simply use my transformer power to fine tune. If I understand Mike Reagan's video properly, Lionel caps draw the peak 18 volts so the smoke unit runs hotter due to more consistent power supply. I have some engines that put out a high output the EPA would like to know about, and that is on "Low"! So if that is the case, what options do you have if you run chopped sines?
If the above sounds like nonsense, consider the source
Stack
I have been running a ZW-L since I built my layout a decade or more ago, I can't say I see a difference in my conventional engine. The seat of the pants HP gains usually don't get reflected against the dyno. G
Since the ZW-L has only been around for about a year, that's a pretty neat trick! Where did you get one a decade ago?
I have been running a ZW-L since I built my layout a decade or more ago, I can't say I see a difference in my conventional engine. The seat of the pants HP gains usually don't get reflected against the dyno. G
Since the ZW-L has only been around for about a year, that's a pretty neat trick! Where did you get one a decade ago?
And you will need 1.21 gigawatts and a flux capacitor to return to current times.
I have been running a ZW-L since I built my layout a decade or more ago, I can't say I see a difference in my conventional engine. The seat of the pants HP gains usually don't get reflected against the dyno. G
Since the ZW-L has only been around for about a year, that's a pretty neat trick! Where did you get one a decade ago?
OOPs, ZW-C. G
Speaking of the C and the L, the C maxes out at 18 vac. Is the L the same?
I think the big difference here is the tolerances. A chopped sin wave has a 5% (or more, there is a standard out there, some electronic guy out there remember?) difference in electronic component tolerance, and being cut it may spike higher than it should. The newer engines using capacitors on rectified DC current level this out. Older AC engines do not have this available, and the spikes in current are hard on electronics, and motors, they naturally want a smooth sin wave.
Modern Lionel smokes better from having a DC current running from a capacitor raising and leveling out the available voltage from the spike in the chopped waves curve. The electro couplers gain a similar advantage.
Having run a 2-4-2 Lionel lionchief scout engine on old track, it appears track is what may cause the control and motor issues, since it would randomly sound off sound effects, like I has pushed the buttons on the remote. In turn it would not while running on its wall wart, or newer track with an AC transformer.
Possibly explaining why some peoples engines run better on chopped vs. smooth. The quality of the rail, length, and how many taps and how the taps relate to each other interacting with the engines electronics. The variance in tolerance in the transformer electronics. That is my hypothesis any way.
I would say run smooth sin wave with conventional, MPC, post and pre war, anything with a mechanical E unit and an old fashioned AC motor and as long as you can with legacy, TMCC, DCC, and modern electronic control methods, assuming it still fully works. Then move up to chopped based systems when they are the only power sources with the necessary amperage. That is just an recommendation based on what I have read on here.
Speaking of the C and the L, the C maxes out at 18 vac. Is the L the same?
Since Lionel specifies TMCC and Legacy at a max of 19 volts, I suspect the ZW-L would logically max out at 18V as well. There is no mention of the maximum voltage in the manual...
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