(41C) Cable Capacity Rating {'⁄%}

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An extract from Underground Coal Mine Power Systems, INTERMITTENT DUTY RATING OF TRAILING CABLES, USDoI, Bureau of Mines, Information Circular 8893, pgs 74-81

" ABSTRACT
Federal Bureau of Mines sponsored research conducted at Penn State University and West Virginia University has resulted in recommendations to the Mine Safety and Health Administration (MSHA) concerning the maximum current ratings for trailing cables used at various duty cycles. If approved, the ratings would permit smaller size cables than those presently required by 30 CFR 18, yet would provide equivalent safety when protected by circuit breakers which include overload trip capabilities. Computer and calculator programs for calculating allowable ampacity (current capacity) are presented.
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METHODS OF CALCULATION
WVU's analysis of the PSU data … provided recommendations for sizing conductors, in the form of equations, nomographs, and a calculator program …
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PROGRAMS
The appendix to this paper gives HP41C … program for calculating individual rating values …
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APPENDIX. —PROGRAMS
HP41C Program, Cable Ampacity Rating Table Buildup—Cycle Time in Minutes, Operating Time in Percent … pg-79 "

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