{"id":97,"date":"2013-10-21T14:39:26","date_gmt":"2013-10-21T06:39:26","guid":{"rendered":"http:\/\/powerquality.sg\/wordpress\/?p=97"},"modified":"2013-10-22T07:07:55","modified_gmt":"2013-10-21T23:07:55","slug":"back-to-basics-true-rms","status":"publish","type":"post","link":"https:\/\/powerquality.sg\/wordpress\/?p=97","title":{"rendered":"Back to Basics &#8211; True RMS"},"content":{"rendered":"<p>There used to be a time whereby the price between a non-True RMS (aka Average Responding) and a True RMS meter\/clamp is pretty significant; so much so that if one is just to measure voltage or current for checking if the circuit is &#8216;Live&#8217; or not, one will go for the cheaper Non-True RMS device.<\/p>\n<p>Recently, price difference have narrowed down quite a bit and in my opinion, one should just get a True RMS meter\/clamp straight away.<\/p>\n<p>Loads today are pretty much almost non-linear these days anyway.<\/p>\n<p>For a pure sinusoidal wave;<\/p>\n<figure id=\"attachment_101\" aria-describedby=\"caption-attachment-101\" style=\"width: 300px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/true-rms-vs-average-responding.png\"><img decoding=\"async\" loading=\"lazy\" class=\"size-medium wp-image-101\" alt=\"true rms vs average responding\" src=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/true-rms-vs-average-responding-300x166.png\" width=\"300\" height=\"166\" srcset=\"https:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/true-rms-vs-average-responding-300x166.png 300w, https:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/true-rms-vs-average-responding.png 520w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-101\" class=\"wp-caption-text\">true rms vs average responding<\/figcaption><\/figure>\n<p>Hence for an average responding meter, it will scale the rectified average of the ac waveform by 1.11.<br \/>\nThis holds true only for pure sinusoidal waveform; which do not exist in the practical world.<\/p>\n<p>The difference in reading can vary from between 5 and 40%, depending on what type of waveform that is being measured.<br \/>\nAn example below shows a difference of about 10%. The load being measured was a combination of a couple of CFL and LED bulbs.<\/p>\n<p>It is funny to me to see some contractors out there who uses a non True RMS meter\/clamp to verify the readings obtained from their expensive PQ meters.<\/p>\n<p>&nbsp;<\/p>\n<dl class=\"wp-caption alignnone\" id=\"attachment_99\" style=\"width: 281px;\">\n<dt class=\"wp-caption-dt\" style=\"display: inline !important;\"><a href=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/truerms.jpg\"><img decoding=\"async\" loading=\"lazy\" class=\"size-medium wp-image-99\" alt=\"True RMS vs Average Rectified Clamp\" src=\"http:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/truerms-271x300.jpg\" width=\"271\" height=\"300\" srcset=\"https:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/truerms-271x300.jpg 271w, https:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/truerms-928x1024.jpg 928w, https:\/\/powerquality.sg\/wordpress\/wp-content\/uploads\/2013\/10\/truerms.jpg 1840w\" sizes=\"(max-width: 271px) 100vw, 271px\" \/><\/a><\/dt>\n<\/dl>\n<dl class=\"wp-caption alignnone\" id=\"attachment_99\" style=\"width: 281px;\">\n<dd class=\"wp-caption-dd\">True RMS vs Average Responding Clamp<\/dd>\n<\/dl>\n<p>*Besides True-RMS capability, one should also check for its Safety CAT category. This is an important safety consideration that should not be disregard.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>There used to be a time whereby the price between a non-True RMS (aka Average Responding) and a True RMS meter\/clamp is pretty significant; so much so that if one is just to measure voltage or current for checking if the circuit is &#8216;Live&#8217; or not, one will go for the cheaper Non-True RMS device. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_newsletter_tier_id":0,"jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[9],"tags":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p41TEZ-1z","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/97"}],"collection":[{"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=97"}],"version-history":[{"count":13,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/97\/revisions"}],"predecessor-version":[{"id":105,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/97\/revisions\/105"}],"wp:attachment":[{"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=97"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=97"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/powerquality.sg\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=97"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}