# Voltage control



## Geochurchi (Aug 7, 2020)

Hi All, we have a 16 VAC buss under the layout, there is a subtrack which has a small train running on it, we would like to control the voltage to reduce the speed a bit without effecting the 16 VAC buss, what is the best way to do this?


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## DonR (Oct 18, 2012)

In order to give you a specific answer we would need to know
the scale trains you are running.

All model trains should have a controller designed for the
scale you operate.

N and HO use a Power Pack that has a control that varies
the DC voltage on the track, thus the speed.

0 Gauge trains use a Transforrner that also has a
control that varies the AC voltage on the track, thus the speed.

You can purchase new or used power packs or transformers at
hobby shops or on line sites such as Amazon, Ebay or Craigslist.

Don


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## CTValleyRR (Jul 26, 2014)

I agree, we need more information. Are you running AC, DC or DCC? I'm guessing the former, except that if you have constant voltage in the bus, how do you control the speed of your trains? Do they just all run at the same speed all the time? I mean, your layout, your rules, but that seems like an odd way to do it.


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## mesenteria (Oct 29, 2015)

Geochurchi said:


> Hi All, we have a 16 VAC buss under the layout, there is a subtrack which has a small train running on it, we would like to control the voltage to reduce the speed a bit without effecting the 16 VAC buss, what is the best way to do this?


Sounds to me like a dimmer would work? I mean, if you are loath to get a proper controller for the scale, perhaps a simple dimmer would work.


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## CTValleyRR (Jul 26, 2014)

mesenteria said:


> Sounds to me like a dimmer would work? I mean, if you are loath to get a proper controller for the scale, perhaps a simple dimmer would work.


That's what I was thinking, too, but I wanted to make sure I understood his set-up before I recommended that.


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## Dennis461 (Jan 5, 2018)

you need one of these...


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## Lemonhawk (Sep 24, 2013)

The variac is probably overkill. It's likely that a simple resistor might work, but rather than conjecture we need more information as what the 16vac bus does.


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## MichaelE (Mar 7, 2018)

Drive-by poster I guess.


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## gunrunnerjohn (Nov 10, 2010)

If it's a fixed voltage reduction, some diode pairs will do the trick.


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