{"id":473,"date":"2019-11-02T20:46:11","date_gmt":"2019-11-02T12:16:11","guid":{"rendered":"http:\/\/people.utm.my\/razman-ayop\/?p=473"},"modified":"2020-05-24T16:59:42","modified_gmt":"2020-05-24T08:29:42","slug":"current-sensor-lem-la55","status":"publish","type":"post","link":"https:\/\/people.utm.my\/razman-ayop\/current-sensor-lem-la55\/","title":{"rendered":"Current Sensor LEM LA55"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-474\" src=\"https:\/\/people.utm.my\/razman-ayop\/wp-content\/uploads\/sites\/2074\/2019\/12\/bvvbvbvbv.jpg\" alt=\"\" width=\"426\" height=\"418\" srcset=\"https:\/\/people.utm.my\/razman-ayop\/wp-content\/uploads\/sites\/2074\/2019\/12\/bvvbvbvbv.jpg 426w, https:\/\/people.utm.my\/razman-ayop\/wp-content\/uploads\/sites\/2074\/2019\/12\/bvvbvbvbv-300x294.jpg 300w\" sizes=\"(max-width: 426px) 100vw, 426px\" \/><\/p>\n<ul>\n<li>The recommended current sensor is the LEM LA55. It is a closed loop hall effect sensor capable of measuring DC and AC. It can measure up to 50 A or 100 A (2 different design). However, for this tutorial, the design is based on 50 A.<\/li>\n<li>The number of primary turns, N<sub>pri<\/sub>, depends on the maximum measured current, I<sub>measure(max)<\/sub>. The I<sub>measure(max)<\/sub> needs to be below 50 A.<br \/>\n<strong><span style=\"color: #0000ff\">N<sub>pri<\/sub> &lt;= 50 \/ I<sub>measure(max)<br \/>\n<\/sub><\/span><\/strong>where N<sub>pri <\/sub>needs to be natural number (1,2,3,4,5,&#8230;&#8230;.)<\/li>\n<li>The <strong><span style=\"color: #0000ff\">R<sub>sec<\/sub> needs to be 30 \u03a9 to 330 \u03a9<\/span> <\/strong>based on the datasheet. If the R<sub>sec<\/sub> becomes higher, the reading becomes non-linear. It is recommended to choose not more than 300 \u2126 to obtain linear reading.<\/li>\n<li>The R<sub>sec<\/sub> depend on the maximum voltage rating for analogue to digital converter (ADC) for the hardware platform.<br \/>\n<span style=\"color: #0000ff\"><strong>R<sub>sec <\/sub>= 2000 V<sub>sensor(max) <\/sub>\/ I<sub>measure(max) <\/sub>\/ N<sub>pri<br \/>\n<\/sub><\/strong><\/span><strong><span style=\"color: #0000ff\">30 \u03a9 &lt;= R<sub>sec<\/sub> &lt;= 330 \u03a9<\/span><\/strong><br \/>\nIf over the limit, the maximum R<sub>sec<\/sub><span style=\"font-size: 1rem\"> (330 \u2126) is used:<br \/>\n<strong><span style=\"color: #0000ff\">V<sub>sensor(actual) <\/sub>= I<sub>measure(max) <\/sub>N<sub>pri <\/sub>R<sub>sec <\/sub>\/ 2000<\/span><\/strong><br \/>\n<\/span><\/li>\n<li>Since the dSPACE ds1104 has 10V ADC, the LV25 are out of range of V<sub>sensor(max)<\/sub>. The LEM LV25 still can be used for the dSPACE ds1104. However, the sensitivity of the measurement is reduced. As a result, the accuracy of the measurement becomes lower. It is recommended to use 300\u00a0\u2126 for R<sub>sec<\/sub> in dSPACE ds1104 application with sensitivity high reduction. However, this is good safety factor if measurement overshoot occurs. To improve the sensitivity of the measurement, the amplifier circuit is needed.<\/li>\n<li>R<sub>sec<\/sub> is recommended to have low tolerance (check the forth colour band at the resistance) and 0.5 W or 1.0 W rating to increase measurement accuracy and reduce the effect from temperature change.<\/li>\n<li>Besides LA55, the LEM LY version is also suitable for the dSPACE ds1104. It is a cheaper option because it is an open loop sensor. It also has a non-adjustable rating. For example LEM LY05 only capable of measuring the current up to 5 Arms.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The recommended current sensor is the LEM LA55. It is a closed loop hall effect sensor capable of measuring DC and AC. It can measure up to 50 A or 100 A (2 different design). However, for this tutorial, the design is based on 50 A. The number of primary turns, Npri, depends on the [&hellip;]<\/p>\n","protected":false},"author":24954,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[32],"tags":[],"class_list":["post-473","post","type-post","status-publish","format-standard","hentry","category-research-guidance"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/posts\/473","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/users\/24954"}],"replies":[{"embeddable":true,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/comments?post=473"}],"version-history":[{"count":1,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/posts\/473\/revisions"}],"predecessor-version":[{"id":475,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/posts\/473\/revisions\/475"}],"wp:attachment":[{"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/media?parent=473"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/categories?post=473"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/people.utm.my\/razman-ayop\/wp-json\/wp\/v2\/tags?post=473"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}