American Radio Relay League wire data slide chart
Date: copyright 1935
Inventory Number: 1991-5-0004
Classification: Slide Rule
Subject:
Cultural Region:
Place of Origin:
Dimensions:
0.3 × 16.7 × 21.5 cm (1/8 × 6 9/16 × 8 7/16 in.)
Bibliography:
Lightning Calculators by the A.R.R.L.
DescriptionSlide chart composed of a circular paper disc attached by a brass fastener to a rectangular paper base.
Printed around the circumference of the irregularly shaped disc are two identical unlabeled scales (one each on the left and right sides). These have values descending from 1,000,000 (near top of disc) to .01 (near bottom of disc). Between the two scales at the top of the disc are several arrows for "WIRE SIZE", pointing outwards and each labeled with a type of metal. Between the two scales at the bottom of the disc are two arrows, also pointing outwards, labeled for "TURNS PER INCH" and "Turns per Centimeter".
Printed near the top of the base of the slide chart, and radiating out from the disc, are four scales. The innermost scale, for "B & S GAUGE", carries values from 0000 to 50. The second scale out is for "BRITISH STANDARD WIRE GAUGE", and carries values from 0000000 to 41. The third scale out is for "DIAMETER IN MILS", and has values descending from 1000 to 1. The outermost scale, for "SIDE OF SQUARE WIRE IN MILS HAVING SAME AREA AS ROUND WIRE SCALE", has values descending from 1000 to 100 and is accompanied by a diagram.
Several additional scales are printed near the bottom of the base of the slide chart, also radiating out from the disc. The three innermost scales are printed in a table and are labeled "DOUBLE COTTON COVERED / TURNS PER INCH" (innermost), "DOUBLE SILK OR SINGLE COTTON / TURNS PER INCH" (center), and "ENAMELED OR SINGLE SILK / TURNS PER INCH" (outermost). The next scale out, with values descending from 1000 to 5, is labeled "TURNS PER INCH FOR BARE WIRE". The two outermost scales are printed in a table for "CURRENT CARRYING / CAPACITY BASED ON / NATIONAL / ELECTRIC CODE", and are labeled "WEATHER PROOF INSULATION" (innermost) and "RUBBER INSULATION" (outermost).
To the left of the disc is printed a scale for "CURRENT CARRYING CAPACITY IN MILLIAMPS / BASED ON INDICATED CIRCULAR MILS PER AMPERE", carrying values from 100 to 500.
Printed around the sides of the disc on the base of the slide chart are a number of labeled arrows. Some of these marked with a red dot.
The base of the slide chart has an orange border, within which the American Radio Relay League's trademark is printed (at top and bottom).
Instructions for using the slide chart, along with a number of example problems, are printed on the back of the chart.
Printed around the circumference of the irregularly shaped disc are two identical unlabeled scales (one each on the left and right sides). These have values descending from 1,000,000 (near top of disc) to .01 (near bottom of disc). Between the two scales at the top of the disc are several arrows for "WIRE SIZE", pointing outwards and each labeled with a type of metal. Between the two scales at the bottom of the disc are two arrows, also pointing outwards, labeled for "TURNS PER INCH" and "Turns per Centimeter".
Printed near the top of the base of the slide chart, and radiating out from the disc, are four scales. The innermost scale, for "B & S GAUGE", carries values from 0000 to 50. The second scale out is for "BRITISH STANDARD WIRE GAUGE", and carries values from 0000000 to 41. The third scale out is for "DIAMETER IN MILS", and has values descending from 1000 to 1. The outermost scale, for "SIDE OF SQUARE WIRE IN MILS HAVING SAME AREA AS ROUND WIRE SCALE", has values descending from 1000 to 100 and is accompanied by a diagram.
Several additional scales are printed near the bottom of the base of the slide chart, also radiating out from the disc. The three innermost scales are printed in a table and are labeled "DOUBLE COTTON COVERED / TURNS PER INCH" (innermost), "DOUBLE SILK OR SINGLE COTTON / TURNS PER INCH" (center), and "ENAMELED OR SINGLE SILK / TURNS PER INCH" (outermost). The next scale out, with values descending from 1000 to 5, is labeled "TURNS PER INCH FOR BARE WIRE". The two outermost scales are printed in a table for "CURRENT CARRYING / CAPACITY BASED ON / NATIONAL / ELECTRIC CODE", and are labeled "WEATHER PROOF INSULATION" (innermost) and "RUBBER INSULATION" (outermost).
To the left of the disc is printed a scale for "CURRENT CARRYING CAPACITY IN MILLIAMPS / BASED ON INDICATED CIRCULAR MILS PER AMPERE", carrying values from 100 to 500.
Printed around the sides of the disc on the base of the slide chart are a number of labeled arrows. Some of these marked with a red dot.
The base of the slide chart has an orange border, within which the American Radio Relay League's trademark is printed (at top and bottom).
Instructions for using the slide chart, along with a number of example problems, are printed on the back of the chart.
Signedface of chart, top edge,center: [ARRL trademark];
face of chart, bottom edge, center: [ARRL trademark];
face, center of disc: PUBLISHED BY / THE AMERICAN RADIO RELAY LEAGUE, INC. / Under License by W.P. Koechel;
back, bottom center: Price FIFTY CENTS Postpaid / Published by THE AMERICAN RADIO RELAY LEAGUE, Inc. West Hartford, Conn.;
back, bottom center: Copyright, 1935, American Radio Relay League Inc. Printed in U.S.A.
face of chart, bottom edge, center: [ARRL trademark];
face, center of disc: PUBLISHED BY / THE AMERICAN RADIO RELAY LEAGUE, INC. / Under License by W.P. Koechel;
back, bottom center: Price FIFTY CENTS Postpaid / Published by THE AMERICAN RADIO RELAY LEAGUE, Inc. West Hartford, Conn.;
back, bottom center: Copyright, 1935, American Radio Relay League Inc. Printed in U.S.A.
Inscribedface, center of disc: LIGHTNING / WIRE / CALCULATOR / TYPE C
FunctionFor calculating data pertaining to wire or a particular size and material.
The user first rotates the disc until the arrow labeled for the material of his wire (disc, top) points to the appropriate value on the appropriate wire size scale (near top of chart base). Then, holding the disc in place, he locates the arrow labeled for the information he requires. The numerical value to which it points indicates the solution to his problem.
Note: Only those arrows marked with red dots can be used for wire made from materials other than copper. The remaining arrows give accurate data only for copper wire.
The user first rotates the disc until the arrow labeled for the material of his wire (disc, top) points to the appropriate value on the appropriate wire size scale (near top of chart base). Then, holding the disc in place, he locates the arrow labeled for the information he requires. The numerical value to which it points indicates the solution to his problem.
Note: Only those arrows marked with red dots can be used for wire made from materials other than copper. The remaining arrows give accurate data only for copper wire.
Primary Sources"Lightening Calculators by the A.R.R.L." West Hartford, CT: The American Redio Relay League, Inc., n.d.
ProvenanceOwned by David P. Wheatland (inv. DW 970).