Controlling track voltage at roundhouse and turntable track

120 VAC Modern light/fan dimmers are chopping the sine wave, not reducing the amplitude. You are trying to use it outside it’s working range.  I suggest dedicating specific channels from your ZW or buy smaller transformers and set them for your desired voltage to power up the roundhouse tracks.  

Ken, all three of the devices you tried to use are designed to see 120 volts AC at their input. They won't work with less voltage than that, and they are not the right kind of devices to use in this situation anyway.

There are a lot of options within the hobby that are designed to do this, but I'm a little out of the loop on the current stuff. I'm sure others who are more up to speed with the current products will chime in here and help you with this.

I'd stick with the controls on the transformer.  If you need more controls, add another transformer.  It's going to be the cheapest and most expedient way.

If you're looking for a fixed voltage to the three sources, there is another pretty efficient way.

Use a bunch of diode pairs, typically the easiest way is using diode bridges.  You can then tap off any voltage in .7 volt increments.  This works for pretty much any input voltage.

Using 8 amp bridges, you can pull a decent amount of power through these before they start overheating.  Note that they're on an aluminum heatsink for that reason.

Picture credit: @stan2004

I'm a bit confused as to why you can't just use the throttle/variable control of one ZW channel to adjust track voltage to the RH-TT.  Or are you saying you want to derive 3 independently adjustable voltages from that one ZW channel?  Or maybe your ZW is inconveniently located and you want on/off toggles and variable control on a control panel near the RH-TT?

As the guys mention, lamp dimmers are meant to operate at household 120V AC input voltage.  MTH makes (made?) a line of so-called "Z-controllers" which in principle do the same thing as a lamp dimmer but works at O-gauge AC input voltage of 20V AC (or so).  These controllers can also activate the conventional bell and whistle by manipulating the AC signal and have a convenient direction button I'd think quite handy for RH-TT operations - things you won't find in a lamp dimmer.   However, there can be thorny issues to deal with trying to power a Z-controller with a multi-output train transformer like a ZW; they are meant to be powered by a dedicated low-voltage AC brick as shown below.

Thanks for the responses. I had experimented with the dimmers, trying to find something to raise and lower the voltage coming from a channel on the ZW.  My main control area is several feet away from my scratch built turntable.  I have several post war locos.  I've recently acquired a couple of lionchief engines with the remotes.  Two of my favorite engines were first generation TMCC.  A Scale Hudson, off the top of my head don't remember if it is K-line or Railking.  The other is the Lionel T1duplex.  Anyhow because of "painting myself" into a corner; I have very limited space near the TT.  I just want to be able to set the voltage at a predetermined level, then walk over and control the locos by using the toggles so as not to send something off like a bat out of heck.  Back story, after using windows based pc's and laptops for over 30 years, tired of viruses and crashes I recently changed to a chromebook.  Haven't really figured out how to send pics from iphone to chromebook.  I would love to attach a few pic to clear up the foggy image i have given to you gentlemen.  Not to mention I had considered placing a dedicated transformer in the area being discussed. First off, wouldn't crossing over the tracks powered by the ZW to the TT track cause a short if it is powered by a separate power source? And the issue of no room.  Shouldn't the whisker tracks, and the track leading in be the same power source?  I'll try to get some pics to clear up what i'm trying to achieve..  Once again I appreciate you taking the time to try to help me.

Ken

No short will occur as long as both transformers are in phase with one another.  That’s how large layouts do it with separate power districts.

While not a cheap solution. Go to  www.dallee.com.  Check out their Hostler throttles. You could use your ZW for power. You could place the Hostler unit near your turntable.
At one time an Al Trol throttle was the hot setup for conventional operators wanting a walkaround throttle. It had to be tethered but it worked well. Never see one offered for sale but they seemed to have sold rather well in their day.  As soon as Lionel came out with the Cab 1 and Powermaster they sort of disappeared. If you could find one it could work for you.

You might want to consider a Powerstat. Old school technology but it would work. Its basically a transformer that is wound around a circular core, and has a rotary carbon wiper to pick off the output voltage; much like a PW transformer. They come in 5 amp and 10 amp flavors. They are intended for use with 120VAC as the input supply, but they will work with low voltage supplies such as a ZW output. I have used them this way in the past.

There is the fully enclosed stand-alone variety, and there is also a panel mount version that would install at your TT or yard.

Rod

@Rod Stewart posted:

You might want to consider a Powerstat. Old school technology but it would work.

I'd go for some small model train transformers, they'll be far cheaper than a Variac/Powerstat and are essentially the exact same thing!  You're hunting flies with a sledgehammer!  Besides, the model train transformers are designed for... MODEL TRAINS!

@gunrunnerjohn posted:

I'd go for some small model train transformers, they'll be far cheaper than a Variac/Powerstat and are essentially the exact same thing!  You're hunting flies with a sledgehammer!  Besides, the model train transformers are designed for... MODEL TRAINS!

Haha, I've hunted flies with bigger weapons than that! I was merely trying to offer an option that the OP might be able to mount local to the yard/TT, which would be less obtrusive and easier to deal with than a transformer. And it can be supplied by a remote mounted ZW or other source, and does not require a local 110VAC source. Nuff said.

Rod

Old school AC and DC conventional here.   My Millhouse TTs have their own little power panel at their pits.  A MRC for each TT plus a MRC and Z-1000 switchable for the tracks.  One of my TTs uses a Dallee yardmaster to turn it's bridge.

I find that a nice smooth throttle helps eyeball the rail heads for alignment.  The next project will be the Millhouse indexing system.