# ac voltage for accessories



## Jwh2000 (Dec 4, 2017)

What do you use to adjust the voltage to accessories for your layout?


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## mopac (Feb 24, 2011)

If you want to adjust the volts you will have to use an AC train transformer. Something
that runs S scale or O scale trains. Most accessories take around 15 or 16 volts. I have
many DC transformers for HO trains that have AC accessory terminals. No adjustment though.
The accessory terminals put out 16 volts. That's what I use. But again, no adjustment.

Most accessories will not work correctly if you apply less than 15 volts.


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## cramden (Oct 13, 2015)

Jwh2000 said:


> What do you use to adjust the voltage to accessories for your layout?


I use the smaller Flyer transformers like the 1 1/2 models. They're usually 50-60 watts and they're cheap to pick up. Just use the variable post instead of the fixed volt post with the base post.The volts range from 7-15 and you can adjust the accessory or even lights to save on bulb life. I've used one on an operating stockyard to keep the cattle from stampeding around the pens. Most bulbs that are 14-18 volts will work fine at 12 volts and they last longer. The best part is just change the throttle up or down for your specific need. Hope this helps.


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## Jwh2000 (Dec 4, 2017)

I want to adjust the speed of the oil drum loader.


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## Jwh2000 (Dec 4, 2017)

also it is tied in with other accessories.


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## cramden (Oct 13, 2015)

If it's an original 779 it should run fine with the 15-16 volt fixed post. However if it's a Lionel remake,( the earlier one that doesn't have the floodlight,) the one I had ran way too fast on the fixed post. It works good if you drop the voltage down. I'm not sure how the newer ones run that have the light on the base. If you wanted to put resistors inline since it's tied to other accessories that might be an option but that's out of my scope of knowledge.


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## AmFlyer (Mar 16, 2012)

The MRC AH101 transformers I use have both 14V and 10 V fixed taps. I use the 10V for street lights. All the original Gilbert accessories including the oil drum loader work fine on the 14V tap.
When using original Gilbert transformers I prefer the 4B to power accessories at reduced voltage from the 7-15V post. The 4B has enough power to throw two turnouts and a semaphore simultaneously from one lever on the controller (think crossover.) The output of the transformer I use is set to 13V. I find the smaller transformers like the 1 1/2 have too high an internal impedance to do this reliably.
I recommend against using resistors, their voltage drop is a function of current. You could use diodes is series but it is easier to use the 7-15V post on a transformer.


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## Jwh2000 (Dec 4, 2017)

I think I will use another transformer, seems to be the way to go.
The loader does not have the streetlight and runs too fast.


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## Jwh2000 (Dec 4, 2017)

I bought a 1 1/2 transformer for 14.50 delivered. Lets hope it works!


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## Scotie (Sep 27, 2013)

You can use strings of diodes to drop and fine tune the voltage for individual accessories. Resistors don't work as well as the drop changes with the current draw. In the attached diagram each diode pair gives a .7 volt drop. You can string as many pairs as needed to get the required drop.
A benefit is with one accessory buss around the layout set to say 16VAC then add dripping diodes at each accessory to "tune" it to the best operating voltage.


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## rkenney (Aug 10, 2013)

Have you considered a Lionel rheostat? Also god for tailoring (reducing) voltages on specific sections of track without the throttle.


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## mopac (Feb 24, 2011)

Scotie, I can see where your charts could be helpful. One problem. I am an electronic idiot. I have a couple questions. I do see that diodes are directional.

What size or value diode are you using. I doubt all diodes are equal.

What is a dripping diode.


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## mopac (Feb 24, 2011)

Good idea rkenney. Those would work. I have seen them.


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## mopac (Feb 24, 2011)

I think the easiest is to do what Jwh2000 has done and got another train transformer.
At least he can get down to 7 volts with a twist of the throttle.


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