# second transformer?



## [email protected] (Aug 19, 2018)

I have 60 ft long O scale layout with 3 layers of track on 1 transformer (MRC).

The layout is divided into two sections. One part is 12 feet wide and the other about 24 feet wide. Is it possible to add a second transformer in the other section to help the existing transformer? There is a lack of power to some of the track.

Thanks


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## gregc (Apr 25, 2015)

no, you can't add a 2nd throttle to boost the power of the first. 
There shouldn't be a need to

are you running more than one train?

if not, is there significant voltage drop between the throttle and various track locations which can be fixed by having a bus and feeders to various track locations.


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## DonR (Oct 18, 2012)

If you have sectional track it is very possible to
lose electrical conductivity. We always suggest
that you power your layout with a bus from the
Transformer. Track drops every 6 feet or so
are connected to the bus. This provides smooth
consistent power to all sections of the layout.

In the meantime you can use your multimeter set
to AC volts. Remove the locos and turnup the
power to about half way. Read the voltage at the
transformer track terminals. Then read at the first track
connection, and at every track section around
the layout. You should get the same reading each
time. When the
voltage drops or fails completely you have found the
poor connection. Likely the rail pins are loose or
need cleaning.

Don


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## Wkolina1 (Aug 31, 2018)

Can someone tell me what a bus is.i am a novice.i seem to lose power when i expand my track.sometimes i have a break in the circuit.


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## gunrunnerjohn (Nov 10, 2010)

First step is to determine how you run. If you run command with constant voltage, you can have all the transformers you like, just break the track up into power districts.

For conventional running, the normal method is a beefier transformer, something like the post-war ZW or perhaps a newer MTH Z-4000.


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## DennyM (Jan 3, 2016)

I use a bus for several different things.


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## DonR (Oct 18, 2012)

Wkolina1 said:


> Can someone tell me what a bus is.i am a novice.i seem to lose power when i expand my track.sometimes i have a break in the circuit.



Modelers call the pair of wires from the DC Power pack
or DCC controller a bus. It usually runs under the table
and 'drops' from the track are connected to it. Drops,
connected to the rails,
are recommended every 6 feet or so of track. This
assures a smooth distribution of power around your
layout and overcomes poor connections by joiners.

You still must keep the rail heads clean of any oils or
other dirt that impairs electrical contact with loco wheels.

Don


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## Shdwdrgn (Dec 23, 2014)

Wkolina1 said:


> Can someone tell me what a bus is.i am a novice.i seem to lose power when i expand my track.sometimes i have a break in the circuit.


A bus line is a heavy-gauge wire run underneath the layout that carries your primary power. Everything, including copper wire, has a resistance to it. That resistance means that the longer your wires are, the less power reaches the end. Note that a large copper wire will have *much* less resistance than your sectional track and rail joiners.

By using a large wire for the bus you reduce the resistance and ensure maximum power reaches to all corners of the layout. Then you can use smaller feeder wires to connect the bus line to the track at various points around your layout. Feeders should be kept as short as possible. This type of setup means that even if you have a break in your rail joiners you still have power coming from multiple points on the layout and power will still likely reach both sides of the break.

It may be that your existing transformer has enough power to run your trains, but the resistance through the track is preventing full power from getting to all sections. Having a bus is only useful if your track is permanently set up, but it will absolutely make a difference in making sure the trains receive the same amount of power everywhere around the layout.


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## gunrunnerjohn (Nov 10, 2010)

And of course, there's this bus...


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## DennyM (Jan 3, 2016)

Shdwdrgn said:


> Wkolina1 said:
> 
> 
> > Can someone tell me what a bus is.i am a novice.i seem to lose power when i expand my track.sometimes i have a break in the circuit.
> ...


I never knew those wires were called bus wires. I always called them trunk lines.


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## DonR (Oct 18, 2012)

Around the Forum we generally refer to the wires
from DCC controllers or DC power packs that
feed track drops as the 'bus'. However, Denny
is also right...they are trunk lines. Guess it's
sorta like the Turnout vs Switch terminology.

It's just less confusing to members for us to be consistent in
the terminology used.

Don


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## tr1 (Mar 9, 2013)

*ampac 780 dual not working as advertised*

I can not get my dual ampac 780 to work properly as advertised.
I have an Atlas common rail layout. that worked before with

2 identical MRC XFMR's.
I'm at a loss on how to get my new MRC dual 780 XFMR to work. 

properly.
Please PM me with instructions on how to get the dual XFMR

to work with dual controls.
Thank you!
Regards,tr1


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## DonR (Oct 18, 2012)

I can't find an on line manual for the MRC dual 780 
power pack. However, MRC says it is designed for
'common rail' layouts.

You have been operating your common rail layout
using two power packs. Note how you connected
the two power packs together to go to the 'common rail'.

The 780 should have EITHER 2 posts for each control
OR a post for the left control, and a post for the right
control. A center post would be connected to your
'common rail' feed. The other two posts would be
connected to the inputs of the block control switches that you
presumably have. If it has 2 posts for each control, you
would connect the two 'negative' posts together and feed
this to your 'common rail' circuit. Each of the other posts
would be input for your block control switches.



Don


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## jimben (Jun 27, 2018)

[email protected] said:


> I have 60 ft long O scale layout with 3 layers of track on 1 transformer (MRC).
> 
> The layout is divided into two sections. One part is 12 feet wide and the other about 24 feet wide. Is it possible to add a second transformer in the other section to help the existing transformer? There is a lack of power to some of the track.
> 
> Thanks


Lack of power? You mean there is voltage, just not enough? It is not likely your transformer/controller. You need to install a track power connector every 8 feet to keep voltage close to same on all sections of track. Nickel-silver and brass are not near as good a conductor as copper and low voltage makes the percent drop worse. I use #20 gauge power wires from controller to track power terminals.


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## tr1 (Mar 9, 2013)

*MRC 500 dc outputs broken*

They fell on the floor pulling out/breaking the dc screw terminal
outputs.
1.)What technique could I employ in repairing the dc outputs.

2.)Is this fixable?

3.)The XFMR is in a copper color metal case.
Thank you,
Regard's,tr1


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## traction fan (Oct 5, 2014)

*Terminal strip*



tr1 said:


> They fell on the floor pulling out/breaking the dc screw terminal
> outputs.
> 1.)What technique could I employ in repairing the dc outputs.
> 
> ...



tr1;

3.) Copper-colored metal cases are common on most MRC power packs.

2.) Yes, it is fixable. You just need to replace the broken terminal strip. 

1.) I'd use a screw terminal strip, also called a "barrier strip"as a replacement for the damaged terminals. These strips are made of black Bakelite and have rectangular silver plates with two screws in each plate, The plates are divided by raised Bakelite walls or barriers to keep adjacent wires from shorting to each other. They are sold by electronic parts dealers like www.allelectronics.com Scroll down the left side to "terminal strips. Look at Cat.# TS-204 & TS-206.

With the power pack unplugged from the wall outlet, simply attach each of the DC output wires from your damaged strip to one of the terminal screws on the new strip. Then wires from the track can be attached to the second screw on each terminal. The strips have holes at each end for mounting them. Mark, center punch, and drill a hole for a screw at each end of the new strip. Be very careful not to drill one little bit further than you have to beyond the metal case. You don't want to drill into any electronics inside your power pack! Also do not use flat-head countersink-shaped wood/sheet metal screws to fasten the terminal strip to the case. Instead use round head, or pan head screws, & a small washer. Bakelite is very brittle. Driving a counter sink screw head into it will split the terminal strip at the mounting hole. Also don't screw in too tightly, also to prevent damage to the strip.

good luck;

Traction Fan:smilie_daumenpos:


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## jimben (Jun 27, 2018)

What you likely have (no picture) is a flat phenolic terminal strip. Here is a 12 position terminal strip listed on ebay. You can cut it to the length & amount of terminals you need.

https://www.ebay.com/itm/TERMINAL-S...326894?hash=item4b1efb356e:g:8xUAAOSw0axZhfTC

Here is the picture of your power controller terminals.

http://www.sumidacrossing.org/Musings/files/t7-back.jpg


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