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Hi Everybody--  On my current, temporary layout (depicted in photo), I wanted a quick, cheap method of protecting the two separate outputs of my Lionel "Z" (250-watt) transformer.  So here is what I did (very old technology):

 

The two primary outputs for running trains are hooked-up in series with each of the "bulbs" shown immediately above the 'Z' .  These are old auto headlamp bulbs, # 1000.  They act as automatic circuit breakers!  Several companies used to make them in the 20's, 30's and 40's.  The specs are:

6-8V, 32 & 32 C. P., Automotive Headlamp, BA15d double contact bayonet base, RP11 Glass, C-2V Dual Filament, 32&32C, 6.2V, 4.19A Maximum, 2C-2V...

The two filaments are hooked in-series, and then, the combination is hooked in-series with your power leads.  For modern equipment, the bulbs don't usually light.  For much older equipment, that have older motors drawing more current, the bulbs may light dimly or pretty darn bright.  If an absolute short, the bulbs may burn out and have to be replaced!

I learned this trick on the giant O-scale trolley layout (130x75 ft) at the Eastbay Model Engineers Society layout in Emeryville, CA. many years ago where I was very active.

These bulbs are hard to find. They date to the days before cars had sealed-beam headlamps.  They used to be made by Eveready, Mazda, Westinghouse, Sylvania and others !

Photo 1.  Ken's temporary 5 x 9 layout.

Photo 2.  Lionel type 'Z' xfmr, Lionel CW-80 xfmr, toggle control box, lamp-type circuit breakers.

Photo 3.  Lionel Type 'Z' 250-watt xfmr.

Photo 4.  Lamp bulb auto-circuit breakers using antique # 1000 headlamp bulbs.

 

The electrical hookup on my NEW layout, starting soon, will be first-class.  Photos will be submitted showing progress !  Have a great day!

KRK

Layout14

100_0531

100_0532

100_0533

Attachments

Images (4)
  • Layout14: Ken's temporary 5 x 9 layout.
  • 100_0531: Lionel 'Z' xfmr, Lionel CW-80. toggle control box, lamp ckt breakers.
  • 100_0532: Lionel Type 'Z' 250-watt xfmr.
  • 100_0533: Home-brew auto ckt breakers using antique # 1000 headlamp bulbs.
Last edited by keyrouteken
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The bulbs are a good choice because the resistance of the bulb is lower for low currents. When the current goes high in the case of a short, the filament will heat up and restrict the current. Lamps are considered good ballast resistors which will pass a more or less constant current over a wide voltage range. That's why lowering the voltage on a bulb, while dimming it, does not save as much current as one would think.

Anyway good one.

I have used bulbs in place of a fuse for circuits that have an intermittent short. Rather than blow 20 fuses when looking for a short in a wiring bundle, when you get close to the problem short, the lamp will light signaling that you have found the bad spot. As well, the lamp lighting will limit the current during the short. Great tool.

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OGR Publishing, Inc., 1310 Eastside Centre Ct, Ste 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

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