Transcription
1Visit the Abrams Railroad Empire athttp://home.comcast.net/ abrams railroad/
About Dwarf Signals Definitions A ground mounted signal A low home signal (protecting the entrance of a route or block of track)Why are dwarf signals used? There isn’t room or clearance for a full-sized signal CostWhen are dwarf signals used? Minor trackage within interlockings Starting signals in passenger terminals To signal little-used sidings In yards, sidings and other places so as not to be confused with blocksignals. This clinic shows indication of how turnout is thrown The dwarf signal usually indicates slow speeds only 2
Prototype Dwarf Signals3
LED FeaturesSolderpadsGreen LEDRed LEDDigi-Key Part # 350-1357-1-ND 350-1357-1-ND Price break1Dialight Part # 597-7701-207F 597-7721-207F25red/greenyellow/greenDescription100 Manufacturer (search for specifications): http://www.dialight.com/Distributors (prices may vary) Digi-Key (parts search): http://www.digikey.com/ Mouser: http://www.mouser.com/catalog/625/38.pdfNewark: http://www.newark.com/ 4 Each.86.75.60Comparative pricing search at Octopart: http://octopart.com/
What Else You NeedLow wattage solder ironOptivisorPaper punchchadSpring-loaded tweezers5
Relative SizesReal world (1:1).1N (1:160)16HO (1:87.1)8.71S (1:64)6.4O (1:48)4.8LEDs packaged in plastic stripLED enlarged viewPaper punchchad.25 in diameter6LED Approximately.1 inch square
Ready to SolderLED face down4 solder pads 4-wire I later switched to using only three wires.7cable tinnedSolder to 4 pads
Two Wires Soldered8
Views of Soldering9
More Views of Soldering10
Finishing 11Fill space with glueAdd shade made frompunched paperColor black with marker
Cable or Individual Wires When you use a cable, the signal tends to be L shaped, especially if thewires are arranged to the rear Individual wires can be arranged to give a vertical profile Use brack straw if you want the signal above ground on a postTilt the head back a little for visibility 12
Determining Ballast Resistance 13DCC signal can be used to directly power LEDPurpose of ballast resistor is to limit current through LEDDon’t operate at maximum ratingsExperimentally increase resistance to achieve satisfactory appearance Purpose is to be visible in normal operating conditions Overdriving LED can shorten life You can get yellow from red-green LED by turning on both, but experiment toget satisfactory color DCC is half-wave symmetric; LED on only 50% timeOperating on DC Increase resistance because duty cycle increased from 50% to 100% DC is on 100% of timeRatings / valuesred-green yellow-greenMax forward current (ma)30 / 3020 / 30Forward voltage2 / 2.11.8 / 2.1DCC track voltage 12v (N)1.0 / 1.5Experimentally determined 1.5 / 1.5ballast resistor (K ohm)
Wiring Signals to Show Turnout PositiontrackSwitchmachinecontactsooowire14
Plant Signals in Layout15
More Pictures16
Links and References 17Model techniques Originator of using Dialite, with alternate mounting als Wiring inspiration and other dwarfshttp://nietzsche.mems.duke.edu/ auro/trains/tech/DCC DWARFS/ Dwarf Signals From Styrenehttp://www.nyx.net/ jpurbric/railroads/dwarfs/Prototype information CROR (Canadian Railway Operating Rules) /mcsele/railroad.htm North American railroad signaling -- explain how operational andsafety rules interact with signaling systems to build an operationaland safe railroadhttp://www.lundsten.dk/us signaling/index.html
DCC signal can be used to directly power LED Purpose of ballast resistor is to limit current through LED Don't operate at maximum ratings
