{"id":28740,"date":"2013-05-21T18:32:50","date_gmt":"2013-05-21T13:02:50","guid":{"rendered":"http:\/\/www.kopykitab.com\/blog\/?p=28740"},"modified":"2013-05-21T18:32:50","modified_gmt":"2013-05-21T13:02:50","slug":"neher-mcgrath-calculations-notes","status":"publish","type":"post","link":"https:\/\/www.kopykitab.com\/blog\/neher-mcgrath-calculations-notes\/","title":{"rendered":"Neher McGrath Calculations Notes"},"content":{"rendered":"<h1 style=\"text-align: center;\">Neher McGrath Calculations Notes<\/h1>\n<table width=\"100%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td width=\"100%\" height=\"60\">\n<p align=\"center\"><span style=\"font-family: Arial; font-size: large;\"><b>Neher-McGrath Calculations<\/b><\/span><\/p>\n<\/td>\n<\/tr>\n<tr>\n<td valign=\"top\" width=\"100%\" height=\"514\">\n<p align=\"justify\"><span style=\"font-family: Arial; font-size: small;\">The Neher-McGrath Calculations provide a method for calculating underground cable temperatures or ampacity ratings and are derived from the following technical paper:<\/span><\/p>\n<p align=\"justify\"><span style=\"font-family: Arial; font-size: small;\">J. H. Neher and M. H. McGrath,<i>&#8220;The Calculation of the Temperature Rise and Load Capability of Cable Systems&#8221;<\/i>, AIEE Transactions, Part III, Volume 76, pp 752-772, October, 1957.<\/span><\/p>\n<p align=\"justify\"><span style=\"font-family: Arial; font-size: small;\">This paper considers the complicated heat transfer issues associated with the determination of underground system ampacities. The paper cites the following basic equation for calculation of a cable ampacity:<\/span><\/p>\n<p align=\"center\"><span style=\"font-family: Arial;\"><img id=\"Picture15\" alt=\"\" src=\"http:\/\/www.calcware.com\/images\/nmcalc.gif\" width=\"458\" height=\"207\" align=\"middle\" border=\"0\" hspace=\"0\">\u00a0<\/span><\/p>\n<p align=\"justify\"><span style=\"font-family: Arial; font-size: small;\">However, this single equation masks the great complexity involved in these procedures. There are scores of complicated equations involved in developing the terms in this equation and those required for temperature calculations. (The paper defines over 80 variables and contains in excess of 70 formulas excluding appendices.) To solve for unique ampacities or temperatures at each cable position, a multiple set of equations must be developed to take into account interference heating from every position in the system, and a matrix solution technique for simultaneous equations utilized.<\/span><\/p>\n<p align=\"justify\"><span style=\"font-family: Arial; font-size: small;\">AmpCalc handles all the complexity and allows the user to quickly and easily determine ampacities for virtually any underground ductbank or direct burial arrangement.<\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p>Neher McGrath Calculations Notes Neher-McGrath Calculations The Neher-McGrath Calculations provide a method for calculating underground cable temperatures or ampacity ratings and are derived from the following technical paper: J. H. Neher and M. H. McGrath,&#8220;The Calculation of the Temperature Rise and Load Capability of Cable Systems&#8221;, AIEE Transactions, Part III, Volume 76, pp 752-772, October, &#8230; <a title=\"Neher McGrath Calculations Notes\" class=\"read-more\" href=\"https:\/\/www.kopykitab.com\/blog\/neher-mcgrath-calculations-notes\/\" aria-label=\"More on Neher McGrath Calculations Notes\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":""},"categories":[4773],"tags":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts\/28740"}],"collection":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/comments?post=28740"}],"version-history":[{"count":0,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/posts\/28740\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/media?parent=28740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/categories?post=28740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.kopykitab.com\/blog\/wp-json\/wp\/v2\/tags?post=28740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}