Power Supplies: Maerklin Blue Transformers

Power Supplies: Maerklin Blue Transformers

 

By Preben Karlsmark

 

We all need power supplies for our train layouts. I am a Maerklin guy using Maerklin HO M-tracks for my totally digital layout and a lot (8) of the old blue transformers. I can almost hear the screams of not to use them. You are almost right about this, but not quite. There are several ways you can put them to use.

We all start with a wall outlet supplying 120V AC; then we go from there. All model train makers offer their own power supplies that are geared for their trains. Their outputs can be either AC or DC. Now let us take a look at the old blue ones from Maerklin.

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The oldest one I deal with is the 280 from the early 50′s. It has 6 outputs on the back. Two outputs for the locomotives ranging from 6V, Maerklin says, but more like 8V (my own measurements) to 16V, and again I measured up to 21V. The next 2 outlets are for lighting, measuring about 19V AC which is ok. The third set of outputs is for turnouts and signals, all solenoids, measuring about 26V AC. As the power to the solenoids is momentary, it does not burn any coils, but it certainly executes each snap to the chosen position in a heartbeat. Just make sure that the buttons on the switch box do not get stuck or hung up.

The next generation of ‘Blues’ features only three outlets. The first one (brown) is the combined common ground for track body, lights and solenoid devices. The second one is for center track (variable), and the third one is for lights and solenoid devices (fixed). The output for the locomotives is variable from approx. 8 – 19V AC; the fixed output supplies about 19V AC for all lights and solenoids.

Maerklin has made a lot of different blue transformers through the years. The main difference is the output wattage and the shape of the transformer. Watch out!! Maerklin makes different transformers for their Z Scale trains. These are not suitable for Maerklin HO.

So, now we have 120V AC going in and various AC power coming out. How do we make this work for what we need in this digital age and LED lighting requiring DC power?

The Maerklin Central Station 2 (CS2) can handle just about any kind of power, AC or DC in a variety according to my Maerklin manual. I use one blue transformer for each of my two boosters (6017). For the CS2, I found one Titan transformer supplying 65 Watt. From the two Maerklin transformers I use the light outputs and the Titan has two fixed outputs and I use the one giving about 20 V AC.

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For everything else on my layout I use DC power. WHY????

 

1. All my lights on the layout are LED’s.

2. Signals have LED’s

3. Lamps in the turnout lantern are being replaced with LED’s when the old      incandescent lamps burn out. Furthermore, there will be no humming from the turnouts solenoids.

4. My mimic board has all LED’s for indicating state of turnouts and signals.

5. The digital controls (ESU) for turnouts and signals all output DC.

6. I can control every turnout and signal both analog (old blue controllers) as well as digitally form the CS2 or my iPad (really cool).

7. My home made train detectors run on DC.

I use one power supply for turnouts, incl. lanterns and signals. I hate when every light on the layout dims because I activate a turnout.

How do I go from AC to DC power?

Rather simple.

I use one full wave bridge rectifier like 25 or 50 amp/50V, available from All Electronics, Radio Shack, Mouser, Digikey and similar electronics suppliers. Cost is around $5.00. It has two inputs for the AC power and two outputs +/-.

Across the two DC outputs I solder one electrolytic capacitor 1000uF/50V. NOTE: The electrolytic capacitors are polarized meaning plus terminal to plus out and the same for the negative. If you happen to do it in reverse you will in no time have a very HOT, STEAMING or EXPLODING capacitor.

Now solder on the two wires to the + and – and you are good to go.

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Showing Bridge Rectifier with capacitor. You can either use spade lugs or solder on directly using the shortest soldering time as possible.

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For instance, for the turnouts and signals I use about 16VDC. First connect all signals and turnouts so you have the full load connected to the power supply. The output voltage varies according to the load and there is also a small voltage drop across the rectifier. Connect the rectifier to the variable outlet normally used for locomotive operation. Attach a DC voltmeter across output terminals on the rectifier and gradually turn up the dial on the transformer until you reach the desired voltage. It is that simple.

Then I use another power supply for 12V DC to power up a lot of street lamps (remember to put resistors in if using LED’s). It also delivers power to a small fan and another motor used for some animated effects.

These are examples of ways to utilize the old blue Maerklin transformers. I have gotten some on eBay for only about $22.00.

 

IMPORTANT NOTES (DISCLAIMER):

WARNING:  THE OLD MARKLIN BLUE TRANSFORMERS LIKE THE 280 WERE FITTED WITH THE OLD AC CORD WHERE THE INSULATION IS MADE FROM RUBBER. THIS RUBBER INSULATION HAS DETORIATED OVER TIME AND CAN CAUSE INTERNAL SHORTS AND EVEN FIRES.

If the shell for the plug consists of two halves held together by a screw, you have one of these. The AC cord needs to be replaced. The later models feature a molded AC plug shell that cannot be taken apart. Those are safe to use as the insulation is made of a polymer far less prone to deterioration. Take this information as a guideline, not gospel. The appearance of the plugs changed during a span of about 20 years.

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Left: Old Plug                 Right: New Plug

WARNING:  IF YOU ARE RUNNING DIGITAL LOCOMOTIVES ON AN ANALOG LAYOUT, DO NOT USE THE OLD BLUE TRANSFORMERS TO OPERATE YOUR LOCOMOTIVES. THEY GIVE OUT TOO MUCH VOLTAGE IF YOU WANT TO USE THE REVERSING FEATURE OF THE TRANSFORMER (PRESS THE DIAL BUTTON). YOU WILL FRY THE DECODER. I KNOW THIS FROM MY OWN EXPERIENCE!!!!!

In this case, you need to use a newer analog transformer. Recommended is the Maerklin #6646 transformer with integrated throttle.

6646

Maerklin #6646

2 Responses to Power Supplies: Maerklin Blue Transformers

  1. Gregory Procter says:

    The first 280 Trafos had a higher voltage for solenoids because the first electric turnouts had a single coil which (I think) alternated in direction. (gleaned from reading pre-war layout book)
    Greg.P.

  2. Blue transformers are really a great idea!! The LEDs and the usage of DC supply makes the system function more effectively. Thanks for sharing the post!!

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