{"id":20625,"date":"2025-10-31T00:25:51","date_gmt":"2025-10-31T00:25:51","guid":{"rendered":"https:\/\/vibromera.eu\/glossary\/api-684\/"},"modified":"2026-05-23T22:14:01","modified_gmt":"2026-05-23T22:14:01","slug":"api-684","status":"publish","type":"glossary","link":"https:\/\/vibromera.eu\/ta\/glossary\/api-684\/","title":{"rendered":"What is API 684? Rotor Dynamics Tutorial Standard"},"content":{"rendered":"<h1>Understanding the API 684 Standard<\/h1>\n\t\t<section class=\"woocommerce hestia-shop products is-shortcode\" id=\"products\" data-sorder=\"hestia_shop\" >\n\t\t\t\t\t\t<div class=\"\">\n\t\t\t\t\t\t<div class=\"hestia-shop-content\">\n\t\t\t<div class=\"row\" data-aos=\"fade-up\" >\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-1\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-1\/\" title=\"Portable balancer &amp; Vibration analyzer Balanset-1A\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Balanset-1A \u0bae\u0bc1\u0bb4\u0bc1\u0bae\u0bc8\u0baf\u0bbe\u0ba9 \u0b95\u0bbf\u0b9f\u0bcd \u0b9a\u0bc1\u0bae\u0bc8\u0baf\u0bc8 \u0b8e\u0b9f\u0bc8 \u0bae\u0bb1\u0bcd\u0bb1\u0bc1\u0bae\u0bcd \u0b85\u0ba4\u0bbf\u0bb0\u0bcd\u0bb5\u0bc1 \u0baa\u0b95\u0bc1\u0baa\u0bcd\u0baa\u0bbe\u0baf\u0bcd\u0bb5\u0bbf\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/09\/77-e1693745667801-272x182.webp 272w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/devices\/\" rel=\"tag\">Devices<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-1\/\" title=\"Portable balancer &amp; Vibration analyzer Balanset-1A\">Portable balancer &amp; Vibration analyzer Balanset-1A<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>1,975.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=986\" data-quantity=\"1\" data-product_id=\"986\" data-product_sku=\"BS-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=986\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_986\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"986\" data-product_sku=\"BS-1\" aria-label=\"Add to cart: \u201cPortable balancer &amp; Vibration analyzer Balanset-1A\u201d\" rel=\"nofollow\" data-success_message=\"\u201cPortable balancer &amp; Vibration analyzer Balanset-1A\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_986\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/vibration-sensor\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/vibration-sensor\/\" title=\"Vibration sensor\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Balanset-1A \u0b85\u0ba4\u0bbf\u0bb0\u0bcd\u0bb5\u0bc1 \u0b9a\u0bc6\u0ba9\u0bcd\u0b9a\u0bb0\u0bcd \u0ba8\u0bc6\u0bb0\u0bc1\u0b95\u0bcd\u0b95\u0bae\u0bbe\u0ba9 \u0baa\u0bbe\u0bb0\u0bcd\u0bb5\u0bc8\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-3.webp 1280w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/parts\/\" rel=\"tag\">Parts<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/vibration-sensor\/\" title=\"Vibration sensor\">Vibration sensor<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>90.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1820\" data-quantity=\"1\" data-product_id=\"1820\" data-product_sku=\"VS-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1820\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1820\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1820\" data-product_sku=\"VS-1\" aria-label=\"Add to cart: \u201cVibration sensor\u201d\" rel=\"nofollow\" data-success_message=\"\u201cVibration sensor\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1820\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/optical-sensor-for-balanset-and-arbalance\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"Optical Sensor (Laser Tachometer)\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Optical Sensor (Laser Tachometer)\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-1536x1023.webp 1536w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-460x306.webp 460w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/ZKqzGXSCCBU.webp 1600w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/parts\/\" rel=\"tag\">Parts<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"Optical Sensor (Laser Tachometer)\">Optical Sensor (Laser Tachometer)<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>124.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1832\" data-quantity=\"1\" data-product_id=\"1832\" data-product_sku=\"Tach-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1832\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1832\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1832\" data-product_sku=\"Tach-1\" aria-label=\"Add to cart: \u201cOptical Sensor (Laser Tachometer)\u201d\" rel=\"nofollow\" data-success_message=\"\u201cOptical Sensor (Laser Tachometer)\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1832\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-4\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-4\/\" title=\"Balanset-4\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Vibromera \u0b9a\u0bc1\u0bae\u0bc8 \u0b9a\u0bae\u0ba8\u0bbf\u0bb2\u0bc8 \u0b95\u0bbf\u0b9f\u0bcd: \u0b95\u0bca\u0ba3\u0bcd\u0b9f \u0bb5\u0bb4\u0b95\u0bcd\u0b95\u0bc1, \u0baa\u0bb2-\u0b9a\u0948\u0ba9\u0bb2\u0bcd \u0b9a\u0bae\u0bbf\u0b95\u0bcd\u0b9e\u0bc8 \u0ba8\u0bbf\u09ac\u0ba8\u0bcd\u0ba4\u0b95\u0bb0\u0bcd, \u0b95\u0bc8\u0baf\u0bc1\u0bae\u0bc8\u0baf\u0bbe\u0ba9 \u0baa\u0b95\u0bc1\u0baa\u0bcd\u0baa\u0bbe\u0baf\u0bcd\u0bb5\u0bbf, \u0b95\u0bbe\u0ba8\u0bcd\u0ba4 \u0b85\u0b9f\u0bbf\u0baa\u0bcd\u0baa\u0b9f\u0bc8, \u0b85\u0ba4\u0bbf\u0bb0\u0bcd\u0bb5\u0bc1 \u0b9a\u0bc6\u0ba9\u0bcd\u0b9a\u0bb0\u0bcd\u0b95\u0bb3\u0bcd, \u0bae\u0bb1\u0bcd\u0bb1\u0bc1\u0bae\u0bcd \u0b9a\u0bc1\u0bb0\u0bc1\u0bb3\u0bbe\u0b95 \u0b95\u0bc7\u0baa\u0bbf\u0bb3\u0bcd\u0b95\u0bb3\u0bcd.\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-18x12.webp 18w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-460x306.webp 460w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2022\/12\/balkom4.webp 640w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/devices\/\" rel=\"tag\">Devices<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-4\/\" title=\"Balanset-4\">Balanset-4<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>6,803.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1833\" data-quantity=\"1\" data-product_id=\"1833\" data-product_sku=\"BS-4\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1833\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1833\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1833\" data-product_sku=\"BS-4\" aria-label=\"Add to cart: \u201cBalanset-4\u201d\" rel=\"nofollow\" data-success_message=\"\u201cBalanset-4\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1833\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div><!-- \/.row --><div class=\"row\">\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/magnet-stand\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/magnet-stand\/\" title=\"Magnetic Stand Insize-60-kgf\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Magnet base.\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-1024x682.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2018\/05\/IMG-36.webp 1280w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/parts\/\" rel=\"tag\">Parts<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/magnet-stand\/\" title=\"Magnetic Stand Insize-60-kgf\">Magnetic Stand Insize-60-kgf<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>46.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1852\" data-quantity=\"1\" data-product_id=\"1852\" data-product_sku=\"MS-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=1852\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_1852\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"1852\" data-product_sku=\"MS-1\" aria-label=\"Add to cart: \u201cMagnetic Stand Insize-60-kgf\u201d\" rel=\"nofollow\" data-success_message=\"\u201cMagnetic Stand Insize-60-kgf\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_1852\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/reflective-tape\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/reflective-tape\/\" title=\"Reflective tape\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Reflective tape\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-16x12.webp 16w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-460x306.webp 460w, https:\/\/vibromera.eu\/wp-content\/uploads\/2023\/05\/s-l1600-272x182.webp 272w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/parts\/\" rel=\"tag\">Parts<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/reflective-tape\/\" title=\"Reflective tape\">Reflective tape<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>10.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=2329\" data-quantity=\"1\" data-product_id=\"2329\" data-product_sku=\"rt-1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=2329\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_2329\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"2329\" data-product_sku=\"rt-1\" aria-label=\"Add to cart: \u201cReflective tape\u201d\" rel=\"nofollow\" data-success_message=\"\u201cReflective tape\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_2329\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"col-ms-6 col-sm-6 col-md-3 shop-item\">\n\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/dynamic-balancer-balanset-1a\/\" class=\"woocommerce-LoopProduct-link woocommerce-loop-product__link\">\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"card-image\">\n\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/vibromera.eu\/ta\/product\/dynamic-balancer-balanset-1a\/\" title=\"Dynamic balancer \u201cBalanset-1A\u201d OEM\">\n\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"230\" height=\"153\" src=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-230x153.webp\" class=\"attachment-woocommerce_thumbnail size-woocommerce_thumbnail\" alt=\"Balanset-1A \u0b95\u0bbf\u0b9f\u0bcd \u0b89\u0bb3\u0bcd\u0bb3\u0b9f\u0b95\u0bcd\u0b95\u0bae\u0bcd \u0b87\u0b9f\u0bc8\u0bae\u0bc1\u0b95 \u0b85\u0bb2\u0b95\u0bc1, \u0b9a\u0bc6\u0ba9\u0bcd\u0b9a\u0bb0\u0bcd\u0b95\u0bb3\u0bcd, tachometer \u0bae\u0bb1\u0bcd\u0bb1\u0bc1\u0bae\u0bcd \u0b85\u0ba3\u0bc1\u0b95\u0bc2\u0b9f\u0bc1\" srcset=\"https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-230x153.webp 230w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-600x400.webp 600w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-300x200.webp 300w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1024x683.webp 1024w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-768x512.webp 768w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-1536x1024.webp 1536w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-2048x1366.webp 2048w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-360x240.webp 360w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-272x182.webp 272w, https:\/\/vibromera.eu\/wp-content\/uploads\/2021\/11\/\u0411\u0430\u043b\u043a\u043e\u043c\u041a\u0438\u0442-scaled-e1732998877834.webp 708w\" sizes=\"auto, (max-width: 230px) 100vw, 230px\" \/>\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<div class=\"ripple-container\"><\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<div class=\"content\">\n\t\t\t\t\t\t\t\t<span class=\"category\"><a href=\"https:\/\/vibromera.eu\/ta\/product-category\/devices\/\" rel=\"tag\">Devices<\/a><\/span>\n\t\t\t\t\t\t\t\t<h4 class=\"card-title\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ta\/product\/dynamic-balancer-balanset-1a\/\" title=\"Dynamic balancer \u201cBalanset-1A\u201d OEM\">Dynamic balancer \u201cBalanset-1A\u201d OEM<\/a>\n\n\t\t\t\t\t\t\t\t<\/h4>\n\n\t\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t\t<div class=\"footer\">\n\n\t\t\t\t\t\t\t\t\t<div class=\"price\"><h4><span class=\"woocommerce-Price-amount amount\"><span class=\"woocommerce-Price-currencySymbol\">\u20ac<\/span>1,735.00<\/span> + VAT (\u0baa\u0bca\u0bb0\u0bc1\u0ba8\u0bcd\u0ba4\u0bc1\u0bae\u0bcd \u0b8e\u0ba9\u0bcd\u0bb1\u0bbe\u0bb2\u0bcd)<\/h4><\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"stats\">\n\t\t\t\t\t\t\t\t\t\t<a rel=\"nofollow\" href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=4193\" data-quantity=\"1\" data-product_id=\"4193\" data-product_sku=\"BS-1OEM\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart btn btn-just-icon btn-simple btn-default\" title=\"Add to cart\" data-no-translation-title=\"\"><i rel=\"tooltip\" data-original-title=\"Add to cart\" class=\"fas fa-cart-plus\" data-no-translation-data-original-title=\"\"><\/i><\/a>\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/a><a href=\"\/ta\/wp-json\/wp\/v2\/glossary\/20625?add-to-cart=4193\" aria-describedby=\"woocommerce_loop_add_to_cart_link_describedby_4193\" data-quantity=\"1\" class=\"button product_type_simple add_to_cart_button ajax_add_to_cart\" data-product_id=\"4193\" data-product_sku=\"BS-1OEM\" aria-label=\"Add to cart: \u201cDynamic balancer \u201cBalanset-1A\u201d OEM\u201d\" rel=\"nofollow\" data-success_message=\"\u201cDynamic balancer \u201cBalanset-1A\u201d OEM\u201d has been added to your cart\" data-no-translation=\"\" data-trp-gettext=\"\" data-no-translation-aria-label=\"\" data-no-translation-data-success_message=\"\">Add to cart<\/a>\t<span id=\"woocommerce_loop_add_to_cart_link_describedby_4193\" class=\"screen-reader-text\">\n\t\t\t<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/section>\n\t\t\n<p><strong>API 684<\/strong> (American Petroleum Institute Standard 684: <em>&#8220;API Standard Paragraphs Rotordynamic Tutorial: Lateral Critical Speeds, Unbalance Response, Stability, Train Torsionals, and Rotor Balancing&#8221;<\/em>) is a comprehensive tutorial document that explains how to perform <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/rotor-dynamics\/\">rotor dynamics<\/a> analysis on turbomachinery. Unlike a prescriptive specification, API 684 is educational: it teaches engineers how to calculate <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/critical-speed\/\">\u0bae\u0bc1\u0b95\u0bcd\u0b95\u0bbf\u0baf \u0bb5\u0bc7\u0b95\u0b99\u0bcd\u0b95\u0bb3\u0bcd<\/a>, predict <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/unbalance\/\">unbalance<\/a> response, assess rotor <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/rotor-instability\/\">stability<\/a>, evaluate <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/torsional-vibration\/\">\u0bae\u0bc1\u0bb1\u0bc1\u0b95\u0bcd\u0b95\u0bc1 \u0b85\u0ba4\u0bbf\u0bb0\u0bcd\u0bb5\u0bc1<\/a>, and establish <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/balancing\/\">\u0b9a\u0bae\u0ba8\u0bbf\u0bb2\u0bc8\u0baa\u0bcd\u0baa\u0b9f\u0bc1\u0ba4\u0bcd\u0ba4\u0bc1\u0ba4\u0bb2\u0bcd<\/a> requirements for the equipment covered by other API standards (API 610 pumps, API 617 compressors, API 612 steam turbines).<\/p>\n<h2>1. Definition: What is API 684?<\/h2>\n<p>API 684 serves as the theoretical foundation and analytical guide that underpins the vibration requirements written into the various API equipment standards. Where those standards state <em>what<\/em> a rotor must achieve, API 684 supplies the <em>how and why<\/em> \u2014 the analysis methods, the derivation of acceptance criteria, and the troubleshooting approaches that rotating-equipment engineers and analysts rely on. Its tutorial style means it reads as much like a textbook as a standard, which is precisely why it is so widely used for training.<\/p>\n<h2>2. Standard Structure<\/h2>\n<p>API 684 is organised into three tutorial parts, moving from lateral behaviour through torsional behaviour to balancing.<\/p>\n<h3>Part 1: Lateral rotor dynamics<\/h3>\n<ul>\n<li><strong>Critical speed analysis:<\/strong> methods for calculating lateral critical speeds and the associated <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/mode-shape\/\">mode shapes<\/a>.<\/li>\n<li><strong>Unbalance response:<\/strong> predicting the <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/vibration\/\">vibration<\/a> a rotor will produce in response to a given unbalance distribution.<\/li>\n<li><strong>\u0ba8\u0bbf\u0bb2\u0bc8\u0ba4\u0bcd\u0ba4\u0ba9\u0bcd\u0bae\u0bc8 \u0baa\u0b95\u0bc1\u0baa\u0bcd\u0baa\u0bbe\u0baf\u0bcd\u0bb5\u0bc1:<\/strong> assessing how much margin a rotor has before self-excited instability sets in.<\/li>\n<li><strong>Modelling techniques:<\/strong> finite-element and transfer-matrix methods for building the rotor-bearing model.<\/li>\n<li><strong>Acceptance criteria:<\/strong> how to judge whether the analysis results are acceptable.<\/li>\n<\/ul>\n<h3>Part 2: Train torsional analysis<\/h3>\n<ul>\n<li><strong>Torsional natural frequencies:<\/strong> calculation methods for the whole shaft train.<\/li>\n<li><strong>Forced response:<\/strong> prediction of twisting vibration from known excitation sources.<\/li>\n<li><strong>Transient analysis:<\/strong> startup, shutdown, and fault conditions such as short-circuit torques.<\/li>\n<li><strong>Acceptance:<\/strong> stress limits and separation margins for safe operation. The broader discipline is covered in <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/torsional-analysis\/\">torsional analysis<\/a>.<\/li>\n<\/ul>\n<h3>Part 3: Rotor balancing<\/h3>\n<ul>\n<li><strong>Balance criteria:<\/strong> application of <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/g-grade\/\">ISO balance quality grades (G-grades)<\/a> \u2014 now defined in the modern ISO 21940-11 series, which superseded the older ISO 1940-1.<\/li>\n<li><strong>Shop balancing:<\/strong> procedures and tolerances for the balancing machine.<\/li>\n<li><strong><a href=\"https:\/\/vibromera.eu\/ta\/glossary\/field-balancing\/\">\u0b95\u0bb3 \u0b9a\u0bae\u0ba8\u0bbf\u0bb2\u0bc8<\/a>:<\/strong> in-situ correction methods on the assembled machine.<\/li>\n<li><strong><a href=\"https:\/\/vibromera.eu\/ta\/glossary\/flexible-rotor\/\">Flexible-rotor<\/a> balancing:<\/strong> the special considerations that apply when a rotor bends near or above its critical speed.<\/li>\n<\/ul>\n<h2>3. Key Concepts Addressed<\/h2>\n<p>Several recurring design rules sit at the heart of the document:<\/p>\n<ul>\n<li><strong>Separation margins:<\/strong> operating speed should sit at least 15\u201320% away from any critical speed, with larger margins demanded of low-damping systems. API 684 gives guidance on evaluating whether a margin is adequate.<\/li>\n<li><strong>Damping requirements:<\/strong> minimum <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/damping\/\">damping<\/a> levels for safe operation, expressed through log-decrement criteria and limits on the amplification factor at each critical speed.<\/li>\n<li><strong>Stability criteria:<\/strong> analytical methods for predicting the onset of instability, determining the threshold of stability, and selecting bearings that keep the rotor stable.<\/li>\n<\/ul>\n<h2>4. Practical Application Across the Machine Life Cycle<\/h2>\n<p>API 684 is used at three distinct stages.<\/p>\n<h3>Design phase<\/h3>\n<p>The manufacturer performs a rotor dynamic analysis using API 684 methods, predicts the critical speeds and unbalance response, documents the work in the vendor submittal, and the purchaser reviews and approves it before metal is cut.<\/p>\n<h3>\u0b86\u0ba3\u0bc8\u0baf\u0bbf\u0b9f\u0bc1\u0ba4\u0bb2\u0bcd<\/h3>\n<p>Once the machine runs, the measured behaviour is compared against the predictions: critical speeds are checked to fall within the predicted range (typically \u00b115%), the unbalance response is confirmed to match the calculations, and <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/campbell-diagram\/\">Campbell \u0bb5\u0bb0\u0bc8\u0baa\u0b9f\u0b99\u0bcd\u0b95\u0bb3\u0bcd<\/a> are validated against the as-built rotor.<\/p>\n<h3>Troubleshooting<\/h3>\n<p>When a problem appears in service, API 684 guidance helps diagnose it: the rotor dynamic model is updated from test data, proposed modifications are evaluated, and their effects are predicted before any change is implemented.<\/p>\n<h2>5. Relationship to Other API Standards and Its Value<\/h2>\n<p>API 684 is the connective tissue between the equipment standards. <strong>API 617 (compressors)<\/strong> references it for rotor dynamics requirements and specifies that analysis must follow API 684 methods, with acceptance criteria derived from its principles. <strong>API 610 (pumps)<\/strong> bases its critical-speed, rotor-dynamics, and balancing requirements on the same document. <strong>API 612 (steam turbines)<\/strong> calls for both lateral and torsional analysis per API 684. It also complements the machinery-protection requirements of <a href=\"https:\/\/vibromera.eu\/ta\/glossary\/api-670\/\">API 670<\/a>, which governs the monitoring instrumentation that watches over the rotor in service.<\/p>\n<p>The value of this shared foundation is threefold. It gives the industry a <strong>standardised approach<\/strong> \u2014 a common methodology that yields consistent analysis quality and lets purchasers compare vendors on equal terms. Its <strong>tutorial format<\/strong> makes it a genuine educational resource and training tool, not merely a list of requirements. And because it is built on <strong>decades of proven practice<\/strong>, it incorporates hard-won lessons learned, reducing the risk of inadequate analysis and improving equipment reliability.<\/p>\n<h2>6. Who Performs the Analysis and What They Deliver<\/h2>\n<p>The analysis is carried out by equipment manufacturers (OEMs), engineering contractors, specialised rotor-dynamics consultants, and end-user engineering departments \u2014 work that requires dedicated software and experienced analysts. A typical deliverable package includes the rotor dynamics report, Campbell diagrams, unbalance-response predictions, a stability analysis, torsional analysis where applicable, and recommended operating-speed ranges. While API 684 governs the deep analytical work on critical turbomachinery, the everyday verification it ultimately calls for \u2014 confirming the actual unbalance response and trimming a rotor in its own bearings \u2014 is exactly what a portable two-channel analyser such as the <a href=\"https:\/\/vibromera.eu\/ta\/product\/balanset-1\/\">Balanset-1A<\/a> does on site, measuring 1\u00d7 amplitude and phase and balancing to an ISO 21940-11 grade.<\/p>\n<hr>\n<p><a href=\"https:\/\/vibromera.eu\/ta\/glossary\/\">\u2190 \u0bae\u0bc1\u0ba4\u0ba9\u0bcd\u0bae\u0bc8 \u0b85\u0b9f\u0bcd\u0b9f\u0bb5\u0ba3\u0bc8\u0b95\u0bcd\u0b95\u0bc1 \u0ba4\u0bbf\u0bb0\u0bc1\u0bae\u0bcd\u0baa\u0bb5\u0bc1\u0bae\u0bcd<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Learn about API 684, comprehensive tutorial standard for lateral and torsional rotor dynamics analysis providing guidance for critical speed prediction and vibration assessment.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[109,112],"tags":[],"class_list":["post-20625","glossary","type-glossary","status-publish","hentry","category-glossary","category-iso-standards"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/glossary\/20625","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/types\/glossary"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/glossary\/20625\/revisions"}],"predecessor-version":[{"id":101192,"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/glossary\/20625\/revisions\/101192"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/media?parent=20625"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/categories?post=20625"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/ta\/wp-json\/wp\/v2\/tags?post=20625"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}