{"id":6531,"date":"2011-05-09T19:08:54","date_gmt":"2011-05-09T12:08:54","guid":{"rendered":"http:\/\/tom.ji42.com\/?p=6531"},"modified":"2011-05-09T19:08:54","modified_gmt":"2011-05-09T12:08:54","slug":"electrical-unit-conversions","status":"publish","type":"post","link":"https:\/\/tom.tomwork.net\/?p=6531","title":{"rendered":"ELECTRICAL UNIT CONVERSIONS"},"content":{"rendered":"<p><span style=\"font-family: Arial; font-size: small;\">The purpose of this document is to provide information, formulas and documentation to take certain electrical values and convert them into other electrical values.\u00a0 The formulas below are known and used universally but we use them here in association with computer, network, telecom and other IT equipment. <\/span><\/p>\n<p><span style=\"color: #0000ff; font-family: Arial; font-size: small;\"><a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#Watts\">To Find Watts<br \/>\n<\/a><span style=\"text-decoration: underline;\"><a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#Volt-Amps\">To Find Volt-Amperes<\/a><\/span><span style=\"text-decoration: underline;\"><br \/>\n<a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#kVA\"> To Find Kilovolt-Amperes<\/a><br \/>\n<a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#kW\"> To Find Kilowatts<\/a><br \/>\n<a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#kW-kVA\"> To Convert Between kW and kVA<\/a><br \/>\n<a href=\"http:\/\/www.abrconsulting.com\/Conversions\/elec-con.htm#BTU\"> TO Find kBTUs from Electrical Values<\/a><\/span><\/span><\/p>\n<p><span style=\"color: #008080; font-family: Arial; font-size: small;\"><span style=\"text-decoration: underline;\">Background<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">It is often necessary to turn voltage, amperage and electrical &#8220;nameplate&#8221; values from computer, network and telecom equipment into kW, KVA and BTU information that can be used to calculate overall power and HVAC loads for IT spaces.\u00a0 The following describes how to take basic electrical values and convert them into other types of electrical values. <\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\"><span style=\"text-decoration: underline;\">NOTE #1<\/span>:<br \/>\nThe informational nameplates on most pieces of computer or network equipment     usually display electrical values.\u00a0 These values can be expressed in     volts, amperes, kilovolt-amperes, watts or some combination of the     foregoing.<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: Arial; font-size: x-small;\"><span style=\"text-decoration: underline;\">NOTE #2<\/span>:<br \/>\nIf you are using equipment nameplate information to develop a power and     cooling profile for architects and engineers, the total power and cooling     values will exceed the actual output of the equipment.\u00a0 Reason:\u00a0     the nameplate value is designed to ensure that the equipment will energize     and run safely.\u00a0 Manufacturers build in a &#8220;safety factor&#8221;     when developing their nameplate data.\u00a0 Some nameplates display     information that is higher than the equipment will ever need &#8211; often up to     20% higher.\u00a0 The result is that, in total, your profile will &#8220;over     engineer&#8221; the power and cooling equipment.\u00a0 Electrical and     mechanical engineers may challenge your figures citing that nameplates     require more power than necessary.<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: Arial; font-size: x-small;\"><span style=\"text-decoration: underline;\">NOTE #3<\/span>:<br \/>\nOur advice:\u00a0 Develop the power and cooling profile using the nameplate     information and the formulas below and use the resultant documentation as     your baseline.\u00a0 Reasons:\u00a0 (1) it&#8217;s the best information available     without doing extensive electrical tests on each piece of equipment.\u00a0     Besides, for most projects, you are being asked to predict equipment     requirements 3-5 years out when much of the equipment you will need hasn&#8217;t been invented     yet.\u00a0 (2) the engineers will not duplicate your work; they do not know     what goes into a data center.\u00a0 They will only     challenge the findings if they appear to be to high.\u00a0 If the engineers     want to challenge your figures, it&#8217;s OK but have them do it in writing and     let them take full responsibility for any modifications.\u00a0\u00a0If you     must lower your estimates, do so.\u00a0 But, document everything.\u00a0     There will come a day in 3-5 years when you will need every amp of power you     predicted.\u00a0 We&#8217;ve had projects where it was very evident within six     months that what we predicted would come true &#8211; sometimes even earlier than     we estimated.<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: Arial; font-size: x-small;\"><span style=\"text-decoration: underline;\">NOTE #4<br \/>\n<\/span>If you are designing a very high-density server room where you will have     racks and racks (or cabinets and cabinets) of 1U and 2U servers tightly     packed, you need to read our article entitled &#8220;<span style=\"text-decoration: underline;\"><a href=\"http:\/\/www.abrconsulting.com\/toolate.htm\">IT     Pros &#8211; Don&#8217;t be Left in the Dust on IT Server Room Design&#8221;<\/a><\/span>. <\/span><\/li>\n<\/ul>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"Watts\"><\/a><!--more-->To Find Watts<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">1.\u00a0\u00a0\u00a0\u00a0 When Volts and Amperes are Known<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> POWER (WATTS) = VOLTS x AMPERES<\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">We have a small server with a nameplate shows     2.5 amps.\u00a0 Given a normal 120 Volt, 60 hz power source\u00a0and the ampere reading from equipment, make the following calculation: <\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> POWER (WATTS) = 120 * 2.5\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ANSWER:\u00a0 300 WATTS<\/span><\/p>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"Volt-Amps\"><\/a>To Find Volt-Amperes (VA)<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">1.\u00a0\u00a0\u00a0\u00a0 Same as above.\u00a0 VOLT-AMPERES (VA) = VOLTS x AMPERES\u00a0\u00a0\u00a0 ANS:\u00a0 300 VA<\/span><\/p>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"kVA\"><\/a>To Find kilovolt-Amperes (kVA)<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">1.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">SINGLE PHASE<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOVOLT-AMPERES (kVA) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> Using the previous example:\u00a0 120 * 2.5 = 300 VA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 300 VA \/ 1000 = .3 kVA<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">2.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">208-240 SINGLE-PHASE (2-POLE SINGLE-PHASE)<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Given:\u00a0 We have a Sun server with an amp rating of 4.7 and requiring a 208-240 power source.\u00a0 We&#8217;ll use 220 volts for our calculations.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOVOLT-AMPERES (kVA) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> 220 x 4.7 = 1034\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 1034 \/ 1000 = 1.034 kVA<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">3.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">THREE-PHASE<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Given:\u00a0 We have a large EMC Symmetrix 3930-18\/-36 storage system with 192     physical volumes.\u00a0 EMC&#8217;s website shows a requirement for a 50-amp 208 VAC     receptacle.\u00a0 For this calculation, we will use 21 amps. Do not calculate any value for the plug or receptacle. <\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOVOLT-AMPERES (kVA) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES x 1.73<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> 208 x 21 x 1.73 = 7,556.64\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 7,556.64 \/ 1000 =\u00a0 7.556 kVA<\/span><\/p>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"kW\"><\/a>To Find Kilowatts<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Finding Kilowatts is a bit more complicated in that the formula includes a value for the &#8220;power factor&#8221;.\u00a0\u00a0The power factor is a nebulous but required value that is different for each electrical device.\u00a0 It involves the efficiency in the use of of the electricity supplied to the system.\u00a0 This factor can vary widely from 60% to\u00a095% and is never published on the equipment nameplate and further, is not often supplied with product information.\u00a0 For purposes of these calculations, we use a power factor of .85.\u00a0 This arbitrary number places a slight inaccuracy into the numbers.\u00a0     Its OK and it gets us very close for the work we need to do. <\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\">1.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">SINGLE PHASE<\/span><\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> Given:\u00a0 We have a medium-sized Compaq server that draws 6.0 amps. <\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOWATT (kW) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES x POWER FACTOR<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> 120 * 6.0 = 720 VA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 720 VA * .85 = 612\u00a0\u00a0\u00a0\u00a0\u00a0 612 \/ 1000 = .612 kW<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">2.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">TWO-PHASE<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Given:\u00a0 We have a Sun server with an amp rating of 4.7 and requiring a 208-240 power source.\u00a0 We&#8217;ll use 220 volts for our calculations.<\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOWATT (kW) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES x POWER FACTOR x 2<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> 220 x 4.7 x 2 = 2068\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2068 x .85 = 1757.8\u00a0\u00a0\u00a0\u00a0\u00a0 1757.8 \/ 1000 = 1.76 kW<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\">3.\u00a0\u00a0\u00a0\u00a0 <span style=\"text-decoration: underline;\">THREE-PHASE<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Given:\u00a0 We have a large EMC Symmetrix 3930-18\/-36 storage system with 192 physical volumes.\u00a0 EMC&#8217;s website shows a requirement for a 50-amp 208 VAC receptacle.\u00a0     For this calculation, we will use 22 amps. Do not calculate the value of the plug or receptacle.\u00a0     Use the value on nameplate. <\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> KILOWATT (kW) = <span style=\"text-decoration: underline;\">VOLTS x AMPERES x POWER FACTOR x 1.73<br \/>\n<\/span> 1000<\/span><\/p>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> 208x22x1.73 = 7,916.48\u00a0\u00a0\u00a0\u00a07,916.48 * .85 = 6,729.008\u00a0\u00a0\u00a0\u00a06,729.008\/1000=6.729 kW<\/span><\/p>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"kW-kVA\"><\/a>To Convert Between kW and kVA<\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">The only difference between kW and kVA is the power factor.\u00a0 Once again, the power factor, unless\u00a0known, is an approximation.\u00a0 For purposes of our calculations, we use a power factor of .85.\u00a0 The kVA\u00a0value is always higher than the value for kW. <\/span><\/li>\n<\/ul>\n<p><span style=\"font-family: Arial; font-size: x-small;\"> kW to kVA\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 kW \/ .85 = SAME VALUE EXPRESSED IN kVA<br \/>\nkVA TO kW\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 kVA * .85 = SAME VALUE EXPRESSED IN kW<\/span><\/p>\n<p><span style=\"text-decoration: underline;\"><span style=\"color: #008080; font-family: Arial; font-size: small;\"><a name=\"BTU\"><\/a>To Find BTUs From Electrical Values <\/span><\/span><\/p>\n<ul>\n<li><span style=\"font-family: Arial; font-size: x-small;\">Known and Given:\u00a0\u00a0 1 kW = 3413 BTUs (or 3.413     kBTUs)<br \/>\n<\/span><\/li>\n<li><span style=\"font-family: Arial; font-size: x-small;\">The above is a generally known value for converting electrical values to BTUs.\u00a0 Many manufacturers publish kW, kVA and BTU in their equipment specifications.\u00a0 Often, dividing the BTU value by 3413 does not equal their published kW value.\u00a0 So much for knowns and givens.\u00a0 Where the information is provided by the manufacturer, use it.\u00a0 Where it is not, use the above formula. <\/span><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The purpose of this document is to provide information, formulas and documentation to take certain electrical values and convert them into other electrical values.\u00a0 The formulas below are known and used universally but we use them here in association with computer, network, telecom and other IT equipment. To Find Watts To Find Volt-Amperes To Find [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[13],"tags":[35,36,47,59,61,63],"class_list":["post-6531","post","type-post","status-publish","format-standard","hentry","category-13","tag-conversions","tag-electrical","tag-kva","tag-unit","tag-va","tag-watts"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6cOVM-1Hl","_links":{"self":[{"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=\/wp\/v2\/posts\/6531","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6531"}],"version-history":[{"count":0,"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=\/wp\/v2\/posts\/6531\/revisions"}],"wp:attachment":[{"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6531"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6531"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tom.tomwork.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6531"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}