Reducing Voltage Output of Brick Transformers

Howdy!  It would make it easier if you could name the transformers you want to reduce to 14 volts or so.  I know Lionel's basic one can be "programmed" to whatever lower voltage you want after manipulating the handles.  (The one that used to come with the Polar Express Train set) 

The easiest and probably cheapest way to drop the voltage is to use a string of diode pairs.

I use a Variac-type transformer to lower the input voltage (would work for multiple bricks) or a TPC 300 to lower the output voltage from a single brick.

You can connect two of them to the variable voltage channels of a TIU and adjust voltage with the remote provided you have DCS.  I have two 180 power bricks connected that way to loops and have never had a problem.

Joe

Why would you fool around with the TIU?  You'd have to reset the voltage every time you fired up the TIU.  The diodes will cost a couple of dollars and solve the problem without any intervention between running sessions.  Two bridge rectifiers will drop the AC voltage about 3V, add more if you need a greater voltage drop.  You can find 6A bridge rectifiers on eBay for less than a dollar.

GRJ solution would be the cheapest. If I didn't already have about 1/2 dozen variacs I would just buy a Post war transformer for accessories. How many do you have? You should be able to find a 1033 (5 amps) for under 25 bucks. Even less for a 25 watt Scout type transformer.

Pete

I suppose the primary reason would be to gain "variable" voltage control which other methods do not offer.

Joe                 

I have 6 (six) MTH Z-750 transformers with nothing to do .  I'm looking for something like GRJ posted.  I don't want to use the controller dodads as they can get bumped, or whatever and then your up to 18 or down to six.  Run the power from the transformers to a distribution block and then on to where ever it's needed.

Thanks for the input, greatly appreciated

eBay: 142062842330

Five 10A bridges for a little over $2, shipped free.  If you need more than five, order two batches.  Less than 50 cents each...

gunrunnerjohn posted:

eBay: 142062842330

Five 10A bridges for a little over $2, shipped free.  If you need more than five, order two batches.  Less than 50 cents each...

Thank you.  Information I was looking for

As I recall, you use screw-terminal strips to make interconnections.  These bridge rectifiers also come in an alternate flatter package that might be easier to mate with the strips.

eBay 262356692356, same price (~50 cents, free shipping)

I've seen Z-750 bricks with both 18V AC and 21V AC outputs.  It should be clearly labeled on brick.

Can you elaborate a bit on what accessories/lights you plan to power?  Taking your original question at face-value, I agree that the diode-dropping method is the expedient way to go. 

But in reality very few modern accessories and lights (especially LEDs) intrinsically operate at 14V AC; in other words there is additional voltage regulation to further reduce the voltage and/or convert it to DC.  At the risk of complicating the discussion, another method to consider is to use the bridge rectifier to convert to unregulated DC at the brick output...then use one or more 99 cent eBay DC-to-DC converter modules to generate whatever regulated DC voltage(s) you need.  In general, if you go this route you will be able to supply, say, 2 or 3 times the number of accessories/lights for the same # of bricks.  More details if there's interest.

Carley,

    IMO messing with a Brick is very limiting in a lot of ways, simply pick up an old KW, many around at more than reasonable prices now, and use it for all you accessory needs, if you have a lot of switches you want to independently power, pick up an old ZW.  You can adjust the voltage as required with either of the 2 old Transformers, simply by moving the handles.  

PCRR/Dave

Tape the handles at voltage desired on a variable transformers.

Thanks for all the suggestions.  But 1) I have these and do not want to SPEND any more money and these have nice little circuit breakers, 2) I have cats, and they are very curious and like to chew tape and wiggle into tight spaces, etc., and closing off the basement is NOT an option.

So, while all your suggestions about buying old transformers, outdoor transformers and taping handles are nice, of which I was already aware, are not choices I want to use.

Thanks guys for your input

stan2004 posted:

As I recall, you use screw-terminal strips to make interconnections.  These bridge rectifiers also come in an alternate flatter package that might be easier to mate with the strips.

eBay 262356692356, same price (~50 cents, free shipping)

I've seen Z-750 bricks with both 18V AC and 21V AC outputs.  It should be clearly labeled on brick.

Can you elaborate a bit on what accessories/lights you plan to power?  Taking your original question at face-value, I agree that the diode-dropping method is the expedient way to go. 

But in reality very few modern accessories and lights (especially LEDs) intrinsically operate at 14V AC; in other words there is additional voltage regulation to further reduce the voltage and/or convert it to DC.  At the risk of complicating the discussion, another method to consider is to use the bridge rectifier to convert to unregulated DC at the brick output...then use one or more 99 cent eBay DC-to-DC converter modules to generate whatever regulated DC voltage(s) you need.  In general, if you go this route you will be able to supply, say, 2 or 3 times the number of accessories/lights for the same # of bricks.  More details if there's interest.

Old Lionel accessories, fuel station, dispatch board, oil derrick, Marx bubbling water tower, to name a few.  Plus a large (10 or more multi light buildings, street lights, etc.) incandescent bulbs.  I'm just trying to use what I have already and supply a consistent amount of voltage.  I have a kitty and she loves to be downstairs with me when ever I'm running or working on my layout.  I want things to be fixed and stable so I won't have unintended changes.  I enjoy her company and have no intentions of prohibiting her from the basement.  She and her sister are good mousers and have proved their worth in keep rodents at bay! lol.

Thanks