[MB069], Letter from Thomas Alva Edison to Charles Batchelor, June 19th, 1882


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[MB069], Letter from Thomas Alva Edison to Charles Batchelor, June 19th, 1882

Editor's Notes

[unsigned TAE autograph letter] "In putting up large installations & for that matter small installations look out for the drop of pressure. Our tables are made for a loss of 5 percent. This is 5 volts now a difference of 5 volts will make the lamp at the machine say 16 candles & the last lamp 6 candles or 25 or 30 candles at the machine and 16 on the last lamp. We have changed that here. We only allow 2 percent loss from the 1st lamp to the last, and make the loss 5, 8, or even 12 percent on the wire leading from the machine, according to circumstances. [diagram] The conductor leading from the machine having no lamps on any difference don't effect while the current on which the lamps are having but 2 volts fall the difference in candle power is not noticeable. Now in your large installations you must look sharp after this and I think in most places you will have to calculate for a loss of 2 percent on the tubes carrying the lights and twn to 12 percent on your feeder, thus: [diagram] [continues another paragraph {annotate with longer, more detailed Insull letter 820810 LB007871}







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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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