Conventional Post War Runs Rough On DCS Variable Channel

The variable outputs of the TIU chop the pure sine waves of your ZW which is causing this rough operation. Pretty much any modern electronic transformer (with built in controls) outputs chopped sine waves including the ZW-L and the the older ZW-C. The exception to this is the MTH Z4000, it creates a simulated sine wave that is very close to pure and does not cause this rough operation with your postwar engines. If you want a large modern electronic power source that runs those postwar engines smoothly with remote control options, go with the Z4000.

My postwar engines have never run better with the ZW-L that replaced my postwar ZW. 

I believe the TIU is outputting a modified sine wave and/or PWM. This will cause the motors to run warmer than if they were run on a pure sine wave power source such as a classic ZW. This isn't necessarily a problem for well maintained motors and therefore isn't a reason why you can't run PW on something like that.

However, if you are satisfied with your classic ZW as a power source, you can install a DPST or equivalent switch to your track block so that you can switch between DCS/TIU and conventional ZW control (of course, you are then ditching the DCS remote for control of conventional locomotives which may be your entire point).

Thanks for the information.  This confirms my suspicion.  Just to verify, there is probably no easy fix to condition the sin wave once the TIU cops it up, is there?  If not, that's ok.  BTW I am using the Lionel 180 watt power brick to power the DCS/TIU system.  Switching over to the MTH Z4000 would not help the sin wave condition exiting the TIU, or would it?  I suspect not.

I am already set up with a method to run my conventional trains via the ZW and the digital trains via DCS by throwing switches and relays.  I suspect I will stay with that.  Just looking at options and was not happy with the sound of the conventional post war motors on DCS TIU variable channel power...

Any other information will be appreciated.  Thanks.

Hi Frank R,

There is another option if you want to run conventional from the DCS remote.  If you can find a Z-4000 Commander, you can directly control a Z-4000 transformer with the DCS remote.  This gives you the option of running conventional engines through one of the TIU's fixed channels with the pseudo smooth sine wave AC current from a Z4K.

Dave Hikel posted:

Hi Frank R,

There is another option if you want to run conventional from the DCS remote.  If you can find a Z-4000 Commander, you can directly control a Z-4000 transformer with the DCS remote.  This gives you the option of running conventional engines through one of the TIU's fixed channels with the pseudo smooth sine wave AC current from a Z4K.

Thanks Dave.

So when powering a fixed TIU channel with a Z4000 transformer, the sin wave does not get chopped up like when using a variable channel? True? Interesting...

When/if I step up to the Z4000, I'll give this a try. For now, the ZW will have to do...

The Z-4000 puts out a synthesized sine wave.  It's not a perfect sine wave, but close enough that most equipment doesn't know the difference.  This is the Z-4000 at 12V out with a 6A resistive load.

Frank R. posted:

So when powering a fixed TIU channel with a Z4000 transformer, the sin wave does not get chopped up like when using a variable channel? True? Interesting...

Correct, the TIU Variable outputs will chop up the sine wave of any power source.

My dad runs his layout with the Z4000 commander remote (or the DCS remote) to operate the Z4000 wirelessly and passes the power through FIXED 1 & FIXED 2 to his mainlines. I bought him a ZW-L thinking that it would be able to replace his Z4000 and his postwar ZW in one shot, but like you he didn't like the extra noise & growl from his postwar engines. The ZW-L got sold and he went back to his Z4k-ZW combo.

The Z4000 is the only (simulated) pure sine transformer that can be operated with a wireless remote.

A Z4000 Receiver just went up for sale on the For Sale Forum, Plug this into a Z4000 transformer and use your DCS remote to operate it.

https://ogrforum.com/...c/140652637262261558

I haven't noticed any "extra noise & growl" operating my postwar engines with my ZW-L.  Just nice smooth operation and they run cooler, too.  I'm happy with the ZW-L.

H1000 posted:

Frank R. posted:

So when powering a fixed TIU channel with a Z4000 transformer, the sin wave does not get chopped up like when using a variable channel? True? Interesting...

Correct, the TIU Variable outputs will chop up the sine wave of any power source.

My dad runs his layout with the Z4000 commander remote (or the DCS remote) to operate the Z4000 wirelessly and passes the power through FIXED 1 & FIXED 2 to his mainlines. I bought him a ZW-L thinking that it would be able to replace his Z4000 and his postwar ZW in one shot, but like you he didn't like the extra noise & growl from his postwar engines. The ZW-L got sold and he went back to his Z4k-ZW combo.

The Z4000 is the only (simulated) pure sine transformer that can be operated with a wireless remote.

Interesting. Do you know if you set the variable channels to Fixed will the output sine wave not be chopped? Just try to understand what I can and cannot get away with.

Good info on the Z4000, thanks.

H1000 posted:

A Z4000 Receiver just went up for sale on the For Sale Forum, Plug this into a Z4000 transformer and use your DCS remote to operate it.

https://ogrforum.com/...c/140652637262261558

Good info. Thanks.

Frank R. posted:

Interesting. Do you know if you set the variable channels to Fixed will the output sine wave not be chopped? Just try to understand what I can and cannot get away with.

Yes, when VAR 1 & 2 are set to FIXED, they will also pass power directly through just like the FIXED 1 & 2. The output will not be chopped.

Steam Crazy posted:

I haven't noticed any "extra noise & growl" operating my postwar engines with my ZW-L.  Just nice smooth operation and they run cooler, too.  I'm happy with the ZW-L.

I wish our experience was similar but unfortunately it isn't. Dad did like the looks of the ZW-L and really liked the analog gauges over the digital readouts on the Z4000. The extra noise was just too much though.

MTH went through great lengths during the development of the Z4000 to make the transformer generate that simulated pure sine wave output... this didn't happen by accident. I'm not saying "don't buy a ZW-L", it is still a great transformer but for those who notice the little things like Frank & my dad do, the Z4000 is the better choice.

H1000 posted:

Steam Crazy posted:

I haven't noticed any "extra noise & growl" operating my postwar engines with my ZW-L.  Just nice smooth operation and they run cooler, too.  I'm happy with the ZW-L.

I wish our experience was similar but unfortunately it isn't. Dad did like the looks of the ZW-L and really liked the analog gauges over the digital readouts on the Z4000. The extra noise was just too much though.

MTH went through great lengths during the development of the Z4000 to make the transformer generate that simulated pure sine wave output... this didn't happen by accident. I'm not saying "don't buy a ZW-L", it is still a great transformer but for those who notice the little things like Frank & my dad do, the Z4000 is the better choice.

So this begs the question...  If the post war ZW has a perfect sun wave, why do the newer generation transformers not?

Frank R. posted:

H1000 posted:

Steam Crazy posted:

I haven't noticed any "extra noise & growl" operating my postwar engines with my ZW-L.  Just nice smooth operation and they run cooler, too.  I'm happy with the ZW-L.

I wish our experience was similar but unfortunately it isn't. Dad did like the looks of the ZW-L and really liked the analog gauges over the digital readouts on the Z4000. The extra noise was just too much though.

MTH went through great lengths during the development of the Z4000 to make the transformer generate that simulated pure sine wave output... this didn't happen by accident. I'm not saying "don't buy a ZW-L", it is still a great transformer but for those who notice the little things like Frank & my dad do, the Z4000 is the better choice.

So this begs the question...  If the post war ZW has a perfect sun wave, why do the newer generation transformers not?

Short answer - Cost.

Slightly longer answer - Safety, additional features, need for more power, easier to manufacture.

I've always considered the ZW as the gold standard for transformers. Anything made to run on three rails needs to work correctly with a ZW (and bell button if needed). If you build a transformer, model it after the ZW in terms of electrical compatibility, I believe this was the goal of MTH when the Z4000 was realized.

Great discussion all. Thanks for all the knowledge shared...

I'm not qualified to answer any of the technical questions about ZW vs ZW-L s Z4000, but here are my reasons for choosing a ZW-L:

1) Cost.  One of my best friends bought it as part of a collection, so I got it cheap.  I'll be honest, I probably would not have paid the going retail price.

2) Power.  Easily runs trains the ZW strained to run at a decent speed.

3) Safety

4) Variable output on all circuits, like the ZW.  Another friend loaned me a Z4000 before I bought the ZW-L and I found the 10 and 14 volt circuits inadequate to power my accessories and lights.  The lights were way too dim.

Having said that, I still like the old ZW and it's in storage for future use or as a backup.

I have observed the following regarding postwar locomotive operation using various systems:

1. TIU variable channel - provides the worse (roughest) operation. Rattles E-units. Motors grind horribly. Especially bad performance at lower voltages. Chopped wave w/ low speed step resolution. Because of latency issues, the DCS app does a very poor job controlling variable channels without occasional losses of control.

2. ZW-L - slightly smoother operation. Chopped wave w/ up to 200 speed steps. For some reason, the ZW-L produces weaker DC horn offsets than a Powermaster, so some horns/whistles don't work so well. Similar speed control performance improvement seen upgrading to TMCC with an AC Commander.

3. Legacy Powermaster - Similar to ZW-L, but with stronger DC offsets and more reliable horn / whistle operation, at least in my experience. Maybe the Powermaster processes the AC sine wave input differently than a ZW-L? For someone who is intent on using DCS, a Powermaster can be a good solution as you run it from the DCS app as a method of running conventional postwar.

4. Postwar ZW - Smoothest operation. I have a toggle where I can instantly switch from a postwar ZW, to a ZW-L. I am perplexed by Steam Crazy who says trains run smoother on his ZW-L. I have run probably 100's of engines, both my own, and test runs of customer repairs, but every engine that I have tested immediately quiets down when I toggle back to the postwar ZW in terms of both E-unit and motor buzz.

I have to admit I like the increased smoke production for pill-type units when using a chopped wave.

But for postwar units converted to liquid (that obviously have no voltage regulator), those smoke units really seem to get charred quickly on chopped wave.

Greg, you may be "perplexed by Steam Crazy who says trains run smoother on his ZW-L", but I'm just reporting what I have experienced.  My postwar trains definitely run better with the ZW-L.  Maybe I'm "crazy"?

Steam Crazy posted:

Greg, you may be "perplexed by Steam Crazy who says trains run smoother on his ZW-L", but I'm just reporting what I have experienced.  My postwar trains definitely run better with the ZW-L.  Maybe I'm "crazy"?

Not just crazy; Steam Crazy joking of course.