# Low-cost Variable Voltage



## Dslot (Sep 2, 2007)

Several people have asked about lowering track voltage for kids and beginners.

In a local store called Discount Electronics, I saw an "AC/DC Universal Adapter" for $7.00. It's a hefty plug-transformer ("wall-wart") with a selector switch for 12, 9, 7.5, 6, 4.5, 3 and 1.5 volts. Delivers 1 amp. It's for operating or charging up battery radios, phones, etc.

I would guess you could set it on 9 or 12 volts for the kids, and use it in place of the standard 18-22 volt wall-wart for reduced speeds. 1 amp ought to power two lanes easily for most out-of-the box cars. 

I can't find this product on the web, but it seems to be an identical unit (different brand name) to the *VX 79NP* converter listed on *this page* for $9.99. Your local Wal-Mart, Target, Fry's or other store may carry something similar.

I've also found that some thrift stores have a wide selection of single-voltage wall warts that have become separated from their devices. These range from 1.5 to 30 volts. A 12-volter with a half-amp to 1-amp output should cost you around one to three bucks. The 9-volt ones could be useful for powering light bulbs on the layout, and the 1.5 to 3 V models for LEDs. Get the highest amperage you can find.

-- D


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## martybauer31 (Jan 27, 2004)

Scale Auto sells one that will power up to 6 G-Jets at once, 3 to 12 volts, 2 Amps, settings at 3, 4.5, 6, 7.5, 9, and 12 Volts. I thinks it's $28, not too bad..... halfway down the page.

http://www.scaleauto.com/bsrt/gjet_car.htm


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## Jerzferno (Aug 19, 2007)

I was one that asked in the past. I found a router voltage regulator that will work perfectly in Harbor freight for 10 bucks.


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## Dslot (Sep 2, 2007)

> *Jerzferno* sez: _I was one that asked in the past. I found a router voltage regulator that will work perfectly in Harbor freight for 10 bucks._


How does that work, Jerz? 

I found a pic on the Harbor Freight site. You'd plug the regulator into the wall and plug the track powerpack(s) into the regulator, right? Then use the dial to control voltage into the pack(s).

Does the knob control a three position switch with just the three fixed settings: High, Med and Low, or does it give gradual full control throughout the entire range?

-- D


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## Grandcheapskate (Jan 5, 2006)

martybauer31 said:


> Scale Auto sells one that will power up to 6 G-Jets at once, 3 to 12 volts, 2 Amps, settings at 3, 4.5, 6, 7.5, 9, and 12 Volts. I thinks it's $28, not too bad..... halfway down the page.
> 
> http://www.scaleauto.com/bsrt/gjet_car.htm


 Does anyone know whether this power supply is rectified, or is it just a higher amp wall wart running at 12 volts? The write-up doesn't mention anything about this.

Thanks...Joe


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## slotone (Dec 11, 2004)

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=43060


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## NTxSlotCars (May 27, 2008)

Yeah, but is the actual power pack affected by this controller? 
I thought a 110v transformer needed 110v to operate properly?


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## Dslot (Sep 2, 2007)

> Rich asks: _... is the actual power pack affected by this controller?
> I thought a 110v transformer needed 110v to operate properly?_


Reduced voltage into the transformer's High Voltage side just results in reduction in voltage out the Low Voltage side.

In the days before transistor throttles, model railroaders eliminated some of the problems caused by rheostat speed controls by leaving the power-pack's speed control set on full throttle, and varying the input voltage to the pack's transformer by using a Variac or variable transformer in the 110v line leading to the pack. 

Variacs are pricey now, but used to be more widely available as military surplus. I found a small one in an electrical surplus store long ago. I used it to control my HO trains for years. Unfortunately, when I got it out of storage a couple of years ago to use for slots, a part had got lost along the way. I don't mind jury-rigging 12 V components, but I'm nowhere near as brave with 110 V hardware, so I'm waiting to see if the missing bit turns up while I'm looking for something else.

*NOTE:* A variable transformer (Variac) has exposed 110 V components and *must* be placed in an *insulated housing* (in case you're tempted to experiment with one).

I don't know if a dimmer wall switch for home lighting could be used instead. It used to be that dimmer switches were not suitable for controlling motors, just lights. But that may be different today. The router control was designed for motors, so should not present a problem.

-- D


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## Jerzferno (Aug 19, 2007)

DSLOT - First the 10 bucks I saw was from a flier they sent me. So sorry about the pricing diffrence. Im planning on plugging in my 4 packs to a power strip, and the power strip to this router control. It seems beefy enough at 15 amps. I was first thinking about a light dimmer switch as you mentioned. But Im retired from my volunteer fire department and dont want any responses to my house. I have a substantial wood shop with one of these on my router. It works great for that. With the draw of the 1/2 hp motor, and slowing it down when needed, it remains constant and barely gets warm to the touch. I think it will be fine for the slots. Yes to your question which you answered yourself. It will provide a gradual reduction as opposed to 3 set positions. I'll let you know how it wokrs? Ordering it tonight. If it doesnt, I have a back up for my router table. LOL


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## Dslot (Sep 2, 2007)

> *Jerzferno* sez: _First the 10 bucks I saw was from a flier they sent me. So sorry about the pricing diffrence._


 No prob, Jerz. I know HF has weekly sales all the time, so I figured you got the ten-buck price off a sale flyer.



> _Im planning on plugging in my 4 packs to a power strip, and the power strip to this router control. It seems beefy enough at 15 amps. _


 Yeah, I'd think 15 amps was enough even for the ultra hi-performance magnet guys (but I'd guess those fellas all have the big-buck variable power supplies, so they won't care much about a gizmo to modulate wall-warts and Aurora's old tin bricks).



> _It will provide a gradual reduction as opposed to 3 set positions. I'll let you know how it wokrs? Ordering it tonight._


Give us the word, when you try it. If I can get a functional replacement for my Variac for only 10 - 15 bucks, I'll be stopping in the Harbor Freight store next time I'm in Austin (but then, I usually do anyway). 

:wave:Thanks for the info.

-- D


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## Jeff Van Stemp (Feb 3, 2009)

I reduced the voltage on my 1/25 track by using elements from a clothes dryer. The elements are made from resistor wire - that's why they get hot and dry your clothes. I simply removed them from an old dryer (free) and fastened them to a board. Just hook the 12 volt power wire (before controller) to one end of the element, and the continuing wire via an alligator clip clipped on for variable settings. I had one wired into each lane so I could alter the speed for each lane. Worked really good for me.


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## Jerzferno (Aug 19, 2007)

DSLOT - Router voltage control ordered. Will have it late in the week. Ill try it out as soon as I get it and let you know how it works?


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## Montoya1 (May 14, 2004)

If you can find a de-badged version of the BSRT G-Jet unit, you can save some wonga.


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## noddaz (Aug 6, 1999)

*You mean...*



Montoya1 said:


> If you can find a de-badged version of the BSRT G-Jet unit, you can save some wonga.


 
This one?

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-536

I have been meaning to buy one for years... lol


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## Montoya1 (May 14, 2004)

Thats the puppy.


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## Jerzferno (Aug 19, 2007)

Thats pretty sweet. Do you use it?


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## 1976Cordoba (Sep 20, 2000)

Is the sticker $8?

:lol:


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## Grandcheapskate (Jan 5, 2006)

noddaz said:


> This one?
> 
> http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-536
> 
> I have been meaning to buy one for years... lol


 Does anyone know if this unit uses full rectification? Great price if you only need one or two. You would need at least two (per lane?) if you wanted to run anything at 18 volts.

Great alternative if you don't need too many and it is fully rectified.

Joe


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## Montoya1 (May 14, 2004)

Jerzferno said:


> Thats pretty sweet. Do you use it?


We use regulated 1200mA units that can be set at 18, 15, 12 or 9V. They cost a tenner.

The $8 markup the BSRT add is pretty reasonable, but in threads like this I think it best to truly help people. I will assume MartyB did not know about the unstickered version. It is rather like knowing to buy 'Wizzard' slip-ons from Penn Valley Hobbies, and save a few cents per tire.


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## Jerzferno (Aug 19, 2007)

Ordered afew more small items from Harbor Frieght. My shippment arrived Friday with the exception of the back ordered router control. LOL I keep ya posted DSLOT.


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## Dslot (Sep 2, 2007)

Jerzferno said:


> Ordered afew more small items from Harbor Frieght. My shippment arrived Friday with the exception of the back ordered router control. LOL I keep ya posted DSLOT.


Aaaaargh!
The suspense is killing me. I'll probably be in Austin Thursday. Maybe the local store will have one. I guess I could always return it if it was unsuitable.

Thanks, Jerz.

-- D


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