{"id":63,"date":"2025-10-31T00:25:51","date_gmt":"2025-10-31T00:25:51","guid":{"rendered":"https:\/\/vibromera.eu\/glossary\/broken-rotor-bars\/"},"modified":"2026-07-03T09:57:04","modified_gmt":"2026-07-03T09:57:04","slug":"broken-rotor-bars","status":"publish","type":"glossary","link":"https:\/\/vibromera.eu\/ga\/glossary\/broken-rotor-bars\/","title":{"rendered":"What are Broken Rotor Bars? Squirrel Cage Motor Failure"},"content":{"rendered":"<h1>Understanding Broken Rotor Bars<\/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\/ga\/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\/ga\/product\/balanset-1\/\" title=\"Portable balancer &#038; 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 full kit portable balancer and vibration analyzer\" 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\/ga\/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\/ga\/product\/balanset-1\/\" title=\"Portable balancer &#038; Vibration analyzer Balanset-1A\">Portable balancer &#038; 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\">&euro;<\/span>1,975.00<\/span> + VAT (if applicable)<\/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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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\/ga\/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\/ga\/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 vibration sensor close-up\" 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\/ga\/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\/ga\/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\">&euro;<\/span>90.00<\/span> + VAT (if applicable)<\/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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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\/ga\/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\/ga\/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\/ga\/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\/ga\/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\">&euro;<\/span>124.00<\/span> + VAT (if applicable)<\/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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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\/ga\/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\/ga\/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 rotor balancing kit: carry case, multi-channel signal conditioner, handheld analyzer, magnetic base, vibration sensors, and coiled cables.\" 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\/ga\/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\/ga\/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 (if applicable)<\/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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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\/ga\/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\/ga\/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\/ga\/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 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class=\"shop-item-title-link\" href=\"https:\/\/vibromera.eu\/ga\/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\">&euro;<\/span>1,735.00<\/span> + VAT (if applicable)<\/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=\"\/ga\/wp-json\/wp\/v2\/glossary\/63?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\" 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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>Broken rotor bars<\/strong> are complete fractures of the conductor bars in the squirrel-cage rotor of an induction motor. The condition is essentially the same as a <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/rotor-bar-defects\/\">rotor bar defect<\/a>, but the term emphasises a full break rather than a crack or a high-resistance joint. When one or more bars sever, current can no longer flow through them, and the resulting electromagnetic asymmetry produces distinctive <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/vibration\/\">vibration<\/a> and current signatures \u2014 <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/sidebands\/\">sidebands<\/a> spaced at the <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/pole-pass-frequency\/\">pole-pass frequency<\/a> (the number of poles \u00d7 the <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/slip-frequency\/\">slip frequency<\/a>) around the <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/running-speed\/\">running speed<\/a>.<\/p>\n<p>Broken bars are especially insidious because they fail as a cascade. One broken bar forces extra current and stress into the bars beside it, which then begin to fail in turn. Caught early \u2014 at the single-broken-bar stage \u2014 the motor can run for months under monitoring; missed, the fault can accelerate to multiple broken bars and a catastrophic rotor failure that demands replacement.<\/p>\n<h2>1. How Rotor Bars Break<\/h2>\n<h3>Thermal Fatigue (Most Common)<\/h3>\n<p>Repeated heating and cooling cycles are the leading cause, and the mechanism is worth following step by step:<\/p>\n<ul>\n<li><strong>Startup current:<\/strong> during a start, the rotor carries 5\u20137\u00d7 normal current in the locked-rotor condition.<\/li>\n<li><strong>Thermal expansion:<\/strong> the aluminium bars expand strongly, with a coefficient around 23 \u00b5m\/m\/\u00b0C.<\/li>\n<li><strong>Constraint:<\/strong> the iron core expands far less (about 12 \u00b5m\/m\/\u00b0C), restraining the bars.<\/li>\n<li><strong>Stress:<\/strong> this differential expansion sets up high thermal stress in the bars.<\/li>\n<li><strong>Fatigue:<\/strong> repeated start cycles drive low-cycle <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/fatigue\/\">fatigue<\/a>.<\/li>\n<li><strong>Crack initiation:<\/strong> cracks usually begin at the bar-to-end-ring junction, the highest-stress point.<\/li>\n<\/ul>\n<h3>Mechanical Stress<\/h3>\n<ul>\n<li><a href=\"https:\/\/vibromera.eu\/ga\/glossary\/centrifugal-force\/\">Centrifugal forces<\/a> at high speed.<\/li>\n<li>Electromagnetic forces during running and starting.<\/li>\n<li>Vibration transmitted from external sources.<\/li>\n<li>Shock loading during starts or sudden load changes.<\/li>\n<\/ul>\n<h3>Manufacturing Defects<\/h3>\n<ul>\n<li><strong>Porosity:<\/strong> voids in cast-aluminium rotors.<\/li>\n<li><strong>Poor bonding:<\/strong> inadequate bar-to-core bonding.<\/li>\n<li><strong>Material inclusions:<\/strong> contaminants trapped in the casting.<\/li>\n<li><strong>Weak end-ring joints:<\/strong> poor bar-to-end-ring connections.<\/li>\n<\/ul>\n<h3>Operating Conditions<\/h3>\n<ul>\n<li><strong>Frequent starting:<\/strong> every start is a thermal and mechanical stress event.<\/li>\n<li><strong>High-inertia loads:<\/strong> long acceleration times prolong bar stress.<\/li>\n<li><strong>Reversing service:<\/strong> plugging creates extreme currents.<\/li>\n<li><strong>Single-phasing:<\/strong> running with one phase lost overloads the remaining rotor bars.<\/li>\n<\/ul>\n<h2>2. The Characteristic Sideband Signature<\/h2>\n<h3>Why Sidebands Appear<\/h3>\n<p>The distinctive diagnostic pattern arises through a clear chain of cause and effect:<\/p>\n<ol>\n<li>A broken bar cannot carry current, creating electrical asymmetry in the rotor.<\/li>\n<li>That asymmetry lags the rotating field by the slip frequency f<sub>s<\/sub> \u2014 the difference between synchronous and rotor speed, in Hz.<\/li>\n<li>It produces a torque pulsation at the pole-pass frequency F<sub>P<\/sub> = number of poles \u00d7 f<sub>s<\/sub> \u2014 equivalently twice the per-unit slip times the line frequency (2\u00b7s\u00b7f<sub>line<\/sub>).<\/li>\n<li>The torque pulsation modulates the 1\u00d7 vibration that comes from ordinary mechanical unbalance.<\/li>\n<li>The result is sidebands spaced at running speed \u00b1 pole-pass-frequency intervals.<\/li>\n<\/ol>\n<h3>Vibration Pattern<\/h3>\n<ul>\n<li><strong>Central peak:<\/strong> 1\u00d7 running speed (f<sub>r<\/sub>).<\/li>\n<li><strong>Lower sideband:<\/strong> f<sub>r<\/sub> \u2212 F<sub>P<\/sub> (where F<sub>P<\/sub> = poles \u00d7 f<sub>s<\/sub> is the pole-pass frequency).<\/li>\n<li><strong>Upper sideband:<\/strong> f<sub>r<\/sub> + F<sub>P<\/sub>.<\/li>\n<li><strong>Multiple sidebands:<\/strong> f<sub>r<\/sub> \u00b1 2F<sub>P<\/sub>, f<sub>r<\/sub> \u00b1 3F<sub>P<\/sub> as severity grows.<\/li>\n<li><strong>Symmetry:<\/strong> the sidebands sit symmetrically around the 1\u00d7 peak.<\/li>\n<\/ul>\n<h3>Worked Example<\/h3>\n<p>A 4-pole, 60 Hz motor at full load:<\/p>\n<ul>\n<li>Synchronous speed: 1800 RPM.<\/li>\n<li>Actual speed: 1750 RPM (29.17 Hz).<\/li>\n<li>Slip: 50 RPM, so the slip frequency f<sub>s<\/sub> = 50\/60 = 0.833 Hz.<\/li>\n<li>Pole-pass frequency: F<sub>P<\/sub> = 4 poles \u00d7 0.833 Hz = 3.33 Hz.<\/li>\n<li><strong>Vibration peaks at:<\/strong> 25.8 Hz, 29.17 Hz and 32.5 Hz.<\/li>\n<li>A broken bar is confirmed by the symmetric sidebands at \u00b13.33 Hz.<\/li>\n<\/ul>\n<p>Because the slip frequency is the whole basis of this pattern, it pays to compute it precisely for the motor in question; the <a href=\"https:\/\/vibromera.eu\/ga\/calculators\/motor-slip-calculator\/\">Motor Slip &amp; Actual RPM Calculator<\/a> does this directly from nameplate data.<\/p>\n<h2>3. Current Signature Analysis (MCSA)<\/h2>\n<p>Motor current analysis reveals a closely related pattern around the <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/electrical-frequency\/\">line frequency<\/a>:<\/p>\n<ul>\n<li><strong>Central peak:<\/strong> line frequency (50 or 60 Hz).<\/li>\n<li><strong>Sidebands:<\/strong> f<sub>line<\/sub> \u00b1 2\u00b7s\u00b7f<sub>line<\/sub>, where s is the per-unit slip \u2014 the same \u00b1F<sub>P<\/sub> spacing as in vibration, because 2\u00b7s\u00b7f<sub>line<\/sub> equals the pole-pass frequency.<\/li>\n<li><strong>Example:<\/strong> the 4-pole motor above (s = 50\/1800 \u2248 2.8%) shows sidebands at 60 \u00b1 3.33 Hz \u2014 that is, at 56.7 Hz and 63.3 Hz.<\/li>\n<li><strong>Advantage:<\/strong> non-invasive and well suited to continuous monitoring.<\/li>\n<li><strong>Sensitivity:<\/strong> often detects broken bars earlier than vibration. The <a href=\"https:\/\/vibromera.eu\/ga\/calculators\/motor-electrical-frequencies\/\">Motor Electrical Defect Frequency Calculator<\/a> predicts these exact current sidebands.<\/li>\n<\/ul>\n<h2>4. Progression Stages<\/h2>\n<h3>Single Broken Bar<\/h3>\n<ul>\n<li>Small sidebands appear, around 20\u201340% of the 1\u00d7 peak.<\/li>\n<li>Slight torque pulsation, often unnoticeable.<\/li>\n<li>Motor performance is nearly normal.<\/li>\n<li>The motor can run for months under monitoring.<\/li>\n<li>Replacement should nonetheless be planned.<\/li>\n<\/ul>\n<h3>Multiple Adjacent Broken Bars<\/h3>\n<ul>\n<li>Strong sidebands, greater than 50% of the 1\u00d7 peak.<\/li>\n<li>Noticeable torque pulsation.<\/li>\n<li>Increased slip and temperature.<\/li>\n<li>Progression accelerating as the adjacent bars overheat.<\/li>\n<li>Replacement becomes urgent \u2014 a matter of weeks.<\/li>\n<\/ul>\n<h3>Severe Condition<\/h3>\n<ul>\n<li>Sidebands may exceed the 1\u00d7 peak amplitude.<\/li>\n<li>Severe torque pulsation reaching the driven equipment.<\/li>\n<li>High vibration and temperature.<\/li>\n<li>Risk of end-ring failure or complete rotor breakdown.<\/li>\n<li>Immediate replacement is required.<\/li>\n<\/ul>\n<h2>5. Detection in the Field<\/h2>\n<h3>Vibration Analysis<\/h3>\n<p>The defining challenge is resolution: the sidebands sit only a few hertz from the 1\u00d7 peak (at the pole-pass frequency, typically 1\u20134 Hz), so the analyser must separate them cleanly.<\/p>\n<ul>\n<li>Use a high-resolution <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/fft\/\">FFT<\/a> \u2014 better than 0.2 Hz resolution \u2014 to resolve the sidebands; the <a href=\"https:\/\/vibromera.eu\/ga\/calculators\/fft-resolution-calculator\/\">FFT Resolution Calculator<\/a> helps you choose the line count and span.<\/li>\n<li>Test the motor under load, since the sidebands grow with current flow.<\/li>\n<li>Calculate the expected slip and pole-pass frequency for the motor in advance.<\/li>\n<li>Search the <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/spectrum\/\">spectrum<\/a> for symmetric sidebands at \u00b1F<sub>P<\/sub> around the 1\u00d7 peak.<\/li>\n<li>Trend the sideband amplitude over time.<\/li>\n<\/ul>\n<p>This work is well within reach of a portable instrument. A two-channel analyser such as the <a href=\"https:\/\/vibromera.eu\/ga\/product\/balanset-1\/\">Balanset-1A<\/a> captures the vibration spectrum at the motor bearing while its optical laser tachometer reads true shaft speed, letting you fix the precise 1\u00d7 frequency, compute the slip, and look for the pole-pass-spaced sidebands that confirm broken bars \u2014 all with the motor running under its normal load. Because the same instrument also measures 1\u00d7 amplitude and phase, it cleanly separates a genuine rotor-bar signature from a simple <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/running-speed\/\">running-speed<\/a> unbalance that would call for balancing rather than a rotor replacement.<\/p>\n<h3>MCSA Testing<\/h3>\n<ul>\n<li>Clamp current probes onto the motor leads.<\/li>\n<li>Acquire the current waveform and compute its FFT.<\/li>\n<li>Look for sidebands at f<sub>line<\/sub> \u00b1 2\u00b7s\u00b7f<sub>line<\/sub> (that is, f<sub>line<\/sub> \u00b1 F<sub>P<\/sub>).<\/li>\n<li>Compare against a healthy-motor baseline.<\/li>\n<li>This can flag a problem before the vibration symptoms become clear.<\/li>\n<\/ul>\n<h2>6. Corrective Actions<\/h2>\n<h3>Immediate Response<\/h3>\n<ul>\n<li>Increase the monitoring frequency \u2014 monthly, then weekly, then daily.<\/li>\n<li>Track the growth rate of the sideband amplitude through <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/trend-analysis\/\">trend analysis<\/a>.<\/li>\n<li>Order a spare motor or plan the rotor replacement.<\/li>\n<li>Reduce the duty cycle if possible, minimising starts.<\/li>\n<li>Document the progression for failure analysis.<\/li>\n<\/ul>\n<h3>Repair Options<\/h3>\n<ul>\n<li><strong>Rotor replacement:<\/strong> the most reliable choice for large motors (over 100 HP).<\/li>\n<li><strong>Rotor recasting:<\/strong> specialised shops can recast aluminium rotors.<\/li>\n<li><strong>Motor replacement:<\/strong> often the most economical route for small motors (under 50 HP).<\/li>\n<li><strong>Root-cause investigation:<\/strong> determine why the bars broke to prevent a recurrence.<\/li>\n<\/ul>\n<h3>Prevention<\/h3>\n<ul>\n<li>Use soft starters or VFDs to cut starting current and thermal stress.<\/li>\n<li>Limit the starting frequency for high-inertia loads.<\/li>\n<li>Specify motors rated for the actual duty cycle \u2014 frequent-start designs for high-cycle service.<\/li>\n<li>Ensure adequate motor ventilation and cooling.<\/li>\n<li>Protect against single-phasing conditions.<\/li>\n<\/ul>\n<p>Broken rotor bars account for only about 10\u201315% of <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/motor-defects\/\">motor failures<\/a>, yet they leave an unmistakable pole-pass sideband signature that supports reliable early detection by vibration or current analysis. Understanding the thermal-fatigue mechanism, recognising the characteristic sideband pattern, and embedding the checks in a <a href=\"https:\/\/vibromera.eu\/ga\/glossary\/condition-monitoring\/\">condition-monitoring<\/a> programme allow a motor to be replaced on a planned basis \u2014 before a single broken bar cascades into multiple bar failures and extended unplanned downtime.<\/p>\n<hr>\n<p><a href=\"https:\/\/vibromera.eu\/ga\/glossary\/\">\u2190 Back to Main Index<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>Learn about broken rotor bars in induction motors, fractured conductor bars creating slip frequency sidebands, torque pulsation, and progressive failure if not detected early.<\/p>","protected":false},"featured_media":0,"template":"","meta":{"ai_generated_summary":"","footnotes":""},"categories":[109,111],"tags":[],"class_list":["post-63","glossary","type-glossary","status-publish","hentry","category-glossary","category-rotor-balancing"],"_links":{"self":[{"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/glossary\/63","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/types\/glossary"}],"version-history":[{"count":2,"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/glossary\/63\/revisions"}],"predecessor-version":[{"id":102161,"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/glossary\/63\/revisions\/102161"}],"wp:attachment":[{"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/media?parent=63"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/categories?post=63"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vibromera.eu\/ga\/wp-json\/wp\/v2\/tags?post=63"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}