{"id":92,"date":"2025-10-31T00:25:51","date_gmt":"2025-10-31T00:25:51","guid":{"rendered":"https:\/\/vibromera.eu\/glossary\/critical-speed\/"},"modified":"2026-05-23T22:47:50","modified_gmt":"2026-05-23T22:47:50","slug":"critical-speed","status":"publish","type":"glossary","link":"https:\/\/vibromera.eu\/mr\/glossary\/critical-speed\/","title":{"rendered":"What is Critical Speed in Rotor Dynamics?"},"content":{"rendered":"<h1>\u0930\u094b\u091f\u0930 \u0921\u093e\u092f\u0928\u0945\u092e\u093f\u0915\u094d\u0938\u092e\u0927\u0940\u0932 \u0915\u094d\u0930\u093f\u091f\u093f\u0915\u0932 \u0938\u094d\u092a\u0940\u0921 \u0938\u092e\u091c\u093e\u0935\u0942\u0928 \u0938\u093e\u0902\u0917\u093f\u0924\u0932\u0947<\/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\/mr\/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\/mr\/product\/balanset-1\/\" title=\"\u092a\u094b\u0930\u094d\u091f\u0947\u092c\u0932 \u092c\u0945\u0932\u0928\u094d\u0938\u0930 \u0906\u0923\u093f \u0915\u0902\u092a\u0928 \u0935\u093f\u0936\u094d\u0932\u0947\u0937\u0915 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 \u0938\u0902\u092a\u0942\u0930\u094d\u0923 \u0915\u093f\u091f \u092a\u094b\u0930\u094d\u091f\u0947\u092c\u0932 \u0938\u0902\u0924\u0941\u0932\u0915 \u0906\u0923\u093f \u0915\u0902\u092a\u0928 \u0935\u093f\u0936\u094d\u0932\u0947\u0937\u0915\" 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\/mr\/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\/mr\/product\/balanset-1\/\" title=\"\u092a\u094b\u0930\u094d\u091f\u0947\u092c\u0932 \u092c\u0945\u0932\u0928\u094d\u0938\u0930 \u0906\u0923\u093f \u0915\u0902\u092a\u0928 \u0935\u093f\u0936\u094d\u0932\u0947\u0937\u0915 Balanset-1A\">\u092a\u094b\u0930\u094d\u091f\u0947\u092c\u0932 \u092c\u0945\u0932\u0947\u0928\u094d\u0938\u0930 &#038; \u0935\u094d\u0939\u093e\u092f\u092c\u094d\u0930\u0947\u0936\u0928 \u0905\u200d\u0945\u0928\u093e\u0932\u093e\u092f\u091d\u0930 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\">&euro;<\/span>1,975.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/product\/vibration-sensor\/\" title=\"\u0915\u0902\u092a\u0928 \u0938\u0902\u0935\u0947\u0926\u0915\">\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 \u0915\u0902\u092a\u0928 \u0938\u0902\u0935\u0947\u0926\u0928\u0936\u0940\u0932 \u091c\u0935\u0933\u0942\u0928\" 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\/mr\/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\/mr\/product\/vibration-sensor\/\" title=\"\u0915\u0902\u092a\u0928 \u0938\u0902\u0935\u0947\u0926\u0915\">\u0915\u0902\u092a\u0928 \u0938\u0902\u0935\u0947\u0926\u0915<\/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\">&euro;<\/span>90.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"\u0911\u092a\u094d\u091f\u093f\u0915\u0932 \u0938\u0947\u0928\u094d\u0938\u0930 (\u0932\u0947\u091d\u0930 \u091f\u0945\u0915\u094b\u092e\u0940\u091f\u0930)\">\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=\"\u0911\u092a\u094d\u091f\u093f\u0915\u0932 \u0938\u0947\u0928\u094d\u0938\u0930 (\u0932\u0947\u091d\u0930 \u091f\u0945\u0915\u094b\u092e\u0940\u091f\u0930)\" 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\/mr\/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\/mr\/product\/optical-sensor-for-balanset-and-arbalance\/\" title=\"\u0911\u092a\u094d\u091f\u093f\u0915\u0932 \u0938\u0947\u0928\u094d\u0938\u0930 (\u0932\u0947\u091d\u0930 \u091f\u0945\u0915\u094b\u092e\u0940\u091f\u0930)\">\u0911\u092a\u094d\u091f\u093f\u0915\u0932 \u0938\u0947\u0928\u094d\u0938\u0930 (\u0932\u0947\u091d\u0930 \u091f\u0945\u0915\u094b\u092e\u0940\u091f\u0930)<\/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\">&euro;<\/span>124.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/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 \u0930\u094b\u091f\u0930 \u0938\u0902\u0924\u0941\u0932\u0928 \u0915\u093f\u091f: \u0935\u0939\u0928 \u0915\u0947\u0938, \u092c\u0939\u0941-\u091a\u0945\u0928\u0932 \u0938\u093f\u0917\u094d\u0928\u0932 \u0915\u0902\u0921\u093f\u0936\u0928\u0930, \u0939\u093e\u0925 \u092a\u0915\u0921\u0928\u0947 \u0935\u093e\u0932\u0940 \u0935\u093f\u0936\u094d\u0932\u0947\u0937\u0915, \u091a\u0941\u0902\u092c\u0915\u0940\u092f \u0906\u0927\u093e\u0930, \u0915\u0902\u092a\u0928 \u0938\u0902\u0935\u0947\u0926\u0915, \u0906\u0923\u093f \u0915\u0949\u0907\u0932 \u0915\u0947\u092c\u0932.\" 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\/mr\/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\/mr\/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\">&euro;<\/span>6,803.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/product\/magnet-stand\/\" title=\"\u092e\u0945\u0917\u094d\u0928\u0947\u091f\u093f\u0915 \u0938\u094d\u091f\u0901\u0921 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\/mr\/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\/mr\/product\/magnet-stand\/\" title=\"\u092e\u0945\u0917\u094d\u0928\u0947\u091f\u093f\u0915 \u0938\u094d\u091f\u0901\u0921 Insize-60-kgf\">\u092e\u0945\u0917\u094d\u0928\u0947\u091f\u093f\u0915 \u0938\u094d\u091f\u0901\u0921 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\">&euro;<\/span>46.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/product\/reflective-tape\/\" title=\"\u092a\u0930\u093e\u0935\u0930\u094d\u0924\u0915 \u091f\u0947\u092a\">\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=\"\u092a\u0930\u093e\u0935\u0930\u094d\u0924\u0915 \u091f\u0947\u092a\" 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\/mr\/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\/mr\/product\/reflective-tape\/\" title=\"\u092a\u0930\u093e\u0935\u0930\u094d\u0924\u0915 \u091f\u0947\u092a\">\u092a\u0930\u093e\u0935\u0930\u094d\u0924\u0915 \u091f\u0947\u092a<\/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\">&euro;<\/span>10.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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\/mr\/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\/mr\/product\/dynamic-balancer-balanset-1a\/\" title=\"\u0921\u093e\u092f\u0928\u093e\u092e\u093f\u0915 \u092c\u0945\u0932\u0928\u094d\u0938\u0930 \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 \u0915\u093f\u091f \u0938\u093e\u092e\u0917\u094d\u0930\u0940 \u0907\u0902\u091f\u0930\u092b\u0947\u0938 \u092f\u0941\u0928\u093f\u091f, \u0938\u0902\u0935\u0947\u0926\u0915, \u091f\u0945\u0915\u094b\u092e\u0940\u091f\u0930 \u0906\u0923\u093f \u0905\u0928\u0941\u0937\u0902\u0917\u0940 \u0938\u0939\" 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\/mr\/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\/mr\/product\/dynamic-balancer-balanset-1a\/\" title=\"\u0921\u093e\u092f\u0928\u093e\u092e\u093f\u0915 \u092c\u0945\u0932\u0928\u094d\u0938\u0930 \u201cBalanset-1A\u201d OEM\">\u0921\u093e\u092f\u0928\u093e\u092e\u093f\u0915 \u092c\u0945\u0932\u0928\u094d\u0938\u0930 \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\">&euro;<\/span>1,735.00<\/span> + VAT (\u0932\u093e\u0917\u0942 \u0905\u0938\u0932\u094d\u092f\u093e\u0938)<\/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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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=\"\/mr\/wp-json\/wp\/v2\/glossary\/92?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>A <strong>critical speed<\/strong> is a rotational speed at which a rotor&#8217;s running frequency coincides with one of its <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/natural-frequency\/\">\u092a\u094d\u0930\u093e\u0915\u0943\u0924\u093f\u0915 \u0935\u093e\u0930\u0902\u0935\u093e\u0930\u0924\u0947\u0936\u0940<\/a> of vibration. When a machine runs at or near a critical speed, <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/resonance\/\">resonance<\/a> takes hold, and even a microscopic amount of <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/residual-unbalance\/\">\u0905\u0935\u0936\u093f\u0937\u094d\u091f \u0905\u0938\u0902\u0924\u0941\u0932\u0928<\/a> is amplified into large, potentially dangerous <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/vibration\/\">vibration<\/a>. Because every rotor possesses several natural frequencies \u2014 one for each mode of vibration, such as the first bending mode, the second bending mode, and so on \u2014 it also has multiple critical speeds. Predicting, separating from, and safely traversing these speeds is one of the central problems of <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/rotor-dynamics\/\">rotor dynamics<\/a>.<\/p>\n<h2>1. Definition: What Is a Critical Speed?<\/h2>\n<p>A spinning rotor is, in effect, a mass-and-stiffness system, and like any such system it has preferred frequencies at which it wants to vibrate. The running speed supplies a once-per-revolution forcing input from unbalance. When the running speed matches a natural frequency, that forcing input arrives in perfect time with the rotor&#8217;s own oscillation, energy accumulates cycle after cycle, and the amplitude swells dramatically. That coincidence point is the critical speed.<\/p>\n<p>The shape the rotor takes as it whips at a critical speed is its <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/mode-shape\/\">\u092e\u094b\u0921 \u0906\u0915\u093e\u0930<\/a>, and the lateral whirling motion that develops is the family of behaviour described under <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/whirl\/\">whirl \u0906\u0923\u093f whip<\/a>. Crucially, a critical speed is not a property of unbalance \u2014 unbalance merely <em>excites<\/em> it. The speed itself is fixed by the rotor&#8217;s mass, geometry, and the stiffness of its shaft and supports.<\/p>\n<h2>2. Why Critical Speed Matters So Much<\/h2>\n<p>Operating a machine at a critical speed, even briefly, can be catastrophic. The consequences include:<\/p>\n<ul>\n<li><strong>\u0905\u0924\u094d\u092f\u0927\u093f\u0915 \u0915\u0902\u092a\u0928:<\/strong> amplitudes can rise by a factor of 10, 20, or more, depending on how much <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/damping\/\">damping<\/a> the system has.<\/li>\n<li><strong>\u0918\u091f\u0915 \u0928\u093f\u0915\u093e\u092e\u0940 \u0939\u094b\u0923\u0947:<\/strong> the high vibration and shaft deflection drive bearing failure, seal damage, and <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/rotor-rub\/\">rubs<\/a> between rotating and stationary parts.<\/li>\n<li><strong>Catastrophic shaft failure:<\/strong> in severe cases the alternating bending stress exceeds the material&#8217;s fatigue limit, cracking or breaking the shaft.<\/li>\n<li><strong>Safety hazards:<\/strong> a failure at high speed endangers personnel and nearby equipment.<\/li>\n<\/ul>\n<p>For all these reasons, machinery is designed with a deliberate <strong>\u0935\u093f\u092d\u093e\u091c\u0928 \u092e\u093e\u0930\u094d\u091c\u093f\u0928<\/strong>: the normal continuous running speed is kept a safe distance from every critical speed.<\/p>\n<h2>3. Rigid vs. Flexible Rotors<\/h2>\n<p>Critical speed is the very concept that divides rotors into two classes:<\/p>\n<ul>\n<li><strong><a href=\"https:\/\/vibromera.eu\/mr\/glossary\/rigid-rotor\/\">Rigid rotor<\/a>:<\/strong> operates <em>\u0916\u093e\u0932\u0940<\/em> its first critical speed. Its shaft does not bend appreciably in service \u2014 typically the slower, stockier machines, balanced to <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/iso-21940-11\/\">ISO 21940-11<\/a> tolerances.<\/li>\n<li><strong><a href=\"https:\/\/vibromera.eu\/mr\/glossary\/flexible-rotor\/\">Flexible rotor<\/a>:<\/strong> designed to run <em>above<\/em> its first (and sometimes second or third) critical speed. Its shaft flexes and bends as it passes through each critical speed during startup and shutdown. Slender, high-speed rotors in turbines and compressors are flexible rotors, and they demand the <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/multi-plane-balancing\/\">\u092c\u0939\u0941-\u092a\u094d\u0932\u0947\u0928 \u0938\u0902\u0924\u0941\u0932\u0928<\/a> techniques covered in <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/iso-21940-12\/\">ISO 21940-12<\/a>.<\/li>\n<\/ul>\n<h2>4. Managing Critical Speeds in Operation<\/h2>\n<p>Since it is often impractical to design a high-speed machine that stays below its first critical speed, engineers combine several strategies to live with them safely.<\/p>\n<h3>4.1 Separation Margin<\/h3>\n<p>The most basic rule is to keep the continuous operating speed away from any critical speed, with a typical margin of \u00b120\u201330%. If a critical speed sits at 3,000 rpm, the machine should not run continuously between roughly 2,400 and 3,600 rpm.<\/p>\n<h3>4.2 Rapid Acceleration and Deceleration<\/h3>\n<p>Flexible rotors that must cross a critical speed are run up and shut down quickly through the danger band. Lingering at a critical speed lets amplitude build to dangerous levels; a brisk pass-through denies the resonance time to grow.<\/p>\n<h3>4.3 Damping<\/h3>\n<p>Damping dissipates vibrational energy and is what caps the peak amplitude at resonance. Bearings \u2014 especially fluid-film <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/journal-bearing\/\">\u091c\u0930\u094d\u0928\u0932 \u092c\u0947\u0905\u0930\u093f\u0902\u0917\u092e\u0927\u094d\u092f\u0947<\/a> \u2014 are a primary source of damping; squeeze-film dampers add more where needed. Optimising bearing design holds the critical-speed peak to a safe, manageable level.<\/p>\n<h3>4.4 Precision Balancing<\/h3>\n<p>Because the vibration at a critical speed is an amplified response to unbalance, the better a rotor is balanced the smaller its forcing function and the lower its peak as it sweeps through resonance. For flexible rotors, modal and multi-plane methods target each mode in turn.<\/p>\n<h2>5. How Critical Speeds Are Identified<\/h2>\n<p>Critical speeds are found both on paper and on the test floor:<\/p>\n<ul>\n<li><strong>Rotor dynamic analysis (RDA):<\/strong> finite-element models built in the design phase predict the critical speeds and mode shapes before metal is cut. Our <a href=\"https:\/\/vibromera.eu\/mr\/calculators\/rotor-critical-speed\/\">\u0930\u094b\u091f\u0930 \u0917\u0902\u092d\u0940\u0930 \u0917\u0924\u0940 \u0915\u0945\u0932\u094d\u0915\u094d\u092f\u0941\u0932\u0947\u091f\u0930<\/a> gives a fast first estimate of a shaft&#8217;s lowest critical speed from its geometry and supports.<\/li>\n<li><strong>Run-up and coast-down tests:<\/strong> the most common experimental method, in which amplitude and phase are plotted against speed during <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/run-up-analysis\/\">\u0917\u0924\u0940 \u0935\u093e\u0922\u0935\u0923\u094d\u092f\u093e\u091a\u093e \u091f\u092a\u094d\u092a\u093e<\/a> or <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/coastdown-analysis\/\">\u092e\u0902\u0926\u093e\u0935\u0942\u0928 \u0925\u093e\u0902\u092c\u0923\u094d\u092f\u093e\u091a\u093e \u091f\u092a\u094d\u092a\u093e<\/a>. A critical speed shows up as a distinct amplitude peak accompanied by the characteristic 180\u00b0 <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/phase\/\">phase<\/a> shift, displayed on a <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/bode-plot\/\">\u092c\u094b\u0921 \u092a\u094d\u0932\u0949\u091f<\/a> or <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/waterfall-plot\/\">\u0935\u0949\u091f\u0930\u092b\u0949\u0932 \u092a\u094d\u0932\u0949\u091f<\/a>.<\/li>\n<li><strong>Impact (bump) testing:<\/strong> striking the stationary rotor with an instrumented hammer excites its natural frequencies, which correspond to its critical speeds \u2014 see <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/bump-test\/\">\u092c\u0902\u092a \u091f\u0947\u0938\u094d\u091f<\/a>.<\/li>\n<\/ul>\n<p>For machines running over a range of speeds, the relationship between excitation orders and natural frequencies is best visualised on a <a href=\"https:\/\/vibromera.eu\/mr\/glossary\/campbell-diagram\/\">Campbell \u0906\u0930\u0947\u0916<\/a>; you can map intersections quickly with the <a href=\"https:\/\/vibromera.eu\/mr\/calculators\/campbell-diagram-calculator\/\">Campbell \u0906\u0930\u0947\u0916 \u0915\u0945\u0932\u094d\u0915\u094d\u092f\u0941\u0932\u0947\u091f\u0930<\/a>.<\/p>\n<h2>6. Confirming the Margin in the Field<\/h2>\n<p>Predicting a critical speed is only half the job; verifying the real machine behaves as predicted is the other half. A portable two-channel analyser such as the <a href=\"https:\/\/vibromera.eu\/mr\/product\/balanset-1\/\">Balanset-1A<\/a> captures 1\u00d7 amplitude and phase against rpm during a run-up or coast-down, so the actual critical-speed location and the height of its resonance peak can be read directly from the trace. If the data shows the machine sitting too close to a critical speed, the same instrument supports the on-site balancing that lowers the forcing function and tames the peak \u2014 letting you confirm the separation margin in the bearings the rotor will actually run in.<\/p>\n<hr>\n<p><a href=\"https:\/\/vibromera.eu\/mr\/glossary\/\">\u2190 \u092e\u0941\u0916\u094d\u092f \u0928\u093f\u0930\u094d\u0926\u0947\u0936\u0915\u093e\u0902\u0915\u0921\u0947 \u092a\u0930\u0924<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Learn about critical speed, the rotational speed at which a rotor becomes dynamically unstable due to resonance. Understand its causes, effects, and how it is managed in machine design.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[109,111],"tags":[],"class_list":["post-92","glossary","type-glossary","status-publish","hentry","category-glossary","category-rotor-balancing"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/glossary\/92","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/types\/glossary"}],"version-history":[{"count":1,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/glossary\/92\/revisions"}],"predecessor-version":[{"id":101380,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/glossary\/92\/revisions\/101380"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/media?parent=92"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/categories?post=92"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/mr\/wp-json\/wp\/v2\/tags?post=92"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}