{"id":8234495,"date":"2026-10-24T17:31:54","date_gmt":"2026-10-24T17:31:54","guid":{"rendered":"https:\/\/scn.eu\/?post_type=scn_guide&#038;p=8234495"},"modified":"2026-10-24T17:31:54","modified_gmt":"2026-10-24T17:31:54","slug":"servo-motors","status":"publish","type":"scn_guide","link":"https:\/\/scn.eu\/en\/guides\/servo-motors\/","title":{"rendered":"Servo motors and servo drives \u2013 how servo systems work"},"content":{"rendered":"<div class=\"scn-guide\">\n<h1>Servo motors and servo drives \u2013 how servo systems work<\/h1>\n<p class=\"g-lead\">A servo system moves a load to the right position, at the right speed and at the right time \u2013 over and over again. Here is how motor, servo drive and encoder work together, how to size an axis and when servo is the right choice.<\/p>\n<div class=\"g-short\"><b class=\"t\">Short answer<\/b><\/p>\n<ul>\n<li><b>Servo system<\/b> \u2013 servo motor, servo drive and encoder, controlled by a motion controller or PLC.<\/li>\n<li><b>Closed loop<\/b> \u2013 the drive constantly compares the command with the actual position and corrects the error, thousands of times per second.<\/li>\n<li><b>Servo or VFD<\/b> \u2013 servo for fast, precise positioning. A VFD for speed control of pumps, fans and conveyors.<\/li>\n<li><b>Sizing<\/b> \u2013 check peak torque, RMS torque, speed and inertia ratio.<\/li>\n<li><b>Communication and safety<\/b> \u2013 EtherCAT, MECHATROLINK or PROFINET to the control system, and STO or SS1 for a safe stop.<\/li>\n<\/ul>\n<\/div>\n<h2>What is a servo system?<\/h2>\n<p>In a servo system, the motor follows a command for position, speed or torque, and an encoder constantly reports where the axis actually is. The system consists of:<\/p>\n<ul>\n<li><b>Servo motor<\/b> \u2013 usually a low-inertia permanent magnet synchronous motor, built for fast acceleration and high short-term overload.<\/li>\n<li><b>Servo drive<\/b> \u2013 also called a servo amplifier, and SERVOPACK at Yaskawa. It powers the motor and controls position, speed and torque.<\/li>\n<li><b>Feedback<\/b> \u2013 an incremental encoder, absolute encoder or resolver on the motor shaft. Modern servo motors often have encoders with 20 bits or more per revolution.<\/li>\n<li><b>Motion control<\/b> \u2013 a PLC or motion controller that calculates the path and sends commands to the drives.<\/li>\n<\/ul>\n<figure><img loading=\"lazy\" src=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp\" alt=\"Control loop: the motion controller sends commands to the servo drive, which controls position, speed and current to the servo motor. The encoder feeds back position and speed.\" width=\"1520\" height=\"488\" loading=\"lazy\" decoding=\"async\"><figcaption>The servo drive controls position, speed and current in three loops, using feedback from the encoder.<\/figcaption><\/figure>\n<p>The drive uses three nested loops, known as cascade control. The inner loop controls current and therefore torque, the next controls speed and the outer loop controls position. The faster the loops, the faster and more stable the axis.<\/p>\n<h2>Servo, VFD or stepper motor?<\/h2>\n<div class=\"g-tbl\">\n<table>\n<thead>\n<tr>\n<th><\/th>\n<th>Servo<\/th>\n<th>VFD<\/th>\n<th>Stepper motor<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td class=\"n\">Control<\/td>\n<td>Closed loop, always with encoder<\/td>\n<td>Usually without encoder<\/td>\n<td>Usually open loop, counts steps<\/td>\n<\/tr>\n<tr>\n<td class=\"n\">Strength<\/td>\n<td>Fast, precise positioning and high dynamics<\/td>\n<td>Speed control and energy saving<\/td>\n<td>Simple, low-cost positioning<\/td>\n<\/tr>\n<tr>\n<td class=\"n\">Torque<\/td>\n<td>High peak torque, even at high speed<\/td>\n<td>Even torque up to rated speed<\/td>\n<td>Drops sharply with speed<\/td>\n<\/tr>\n<tr>\n<td class=\"n\">Weakness<\/td>\n<td>Needs tuning<\/td>\n<td>Limited dynamics<\/td>\n<td>Can lose steps unnoticed<\/td>\n<\/tr>\n<tr>\n<td class=\"n\">Examples<\/td>\n<td>Packaging, robots, CNC<\/td>\n<td>Pumps, fans, conveyors<\/td>\n<td>Small axes and dosing units<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The boundaries have blurred. Some VFDs can position with an encoder, and closed-loop stepper motors exist. But when several axes must move in sync, with short cycle times and high accuracy, servo is almost always the right choice.<\/p>\n<h2>Rotary, linear and direct drive motors<\/h2>\n<ul>\n<li><b>Rotary servo motors<\/b> \u2013 the usual choice, connected to the load through a gearbox, ball screw, toothed belt or rack. Available with low inertia for fast axes, medium inertia for heavier loads and with a holding brake for vertical axes.<\/li>\n<li><b>Linear motors<\/b> \u2013 a flat, straight motor that drives the carriage directly. Without a ball screw or belt, there is no backlash and no wear in the transmission.<\/li>\n<li><b>Direct drive motors (torque motors)<\/b> \u2013 drive a rotary table or shaft directly, with no gearbox. High torque, high stiffness and no backlash.<\/li>\n<\/ul>\n<p>An <b>incremental encoder<\/b> needs a homing run after a power failure. An <b>absolute encoder<\/b> knows the position as soon as power returns, and multi-turn encoders also count revolutions, with or without a battery. In robots, presses and axes where homing is awkward, absolute encoders are standard.<\/p>\n<h2>How to size a servo axis<\/h2>\n<p>Start with the motion, not the motor: distance, time, dwell and load. Then check four things:<\/p>\n<ol>\n<li><b>Peak torque<\/b> during acceleration, including friction and external forces. It must be below the motor maximum torque, which is often about three times rated torque.<\/li>\n<li><b>RMS torque<\/b> over the whole cycle. It determines heating and must be below rated torque.<\/li>\n<li><b>Speed<\/b> \u2013 the highest speed in the motion must be below the motor maximum speed, with margin.<\/li>\n<li><b>Inertia ratio<\/b> \u2013 the load inertia referred to the motor shaft, compared with the motor inertia.<\/li>\n<\/ol>\n<figure><img loading=\"lazy\" src=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f2-en.webp\" alt=\"Servo motor connected through a gearbox with ratio i to a load. The load inertia seen by the motor is the load inertia divided by i squared.\" width=\"1520\" height=\"536\" loading=\"lazy\" decoding=\"async\"><figcaption>A gearbox reduces the load inertia seen by the motor by the square of the ratio.<\/figcaption><\/figure>\n<p>A common rule of thumb is to keep the inertia ratio below about 10:1, and lower for highly dynamic axes. Drives with vibration suppression can handle more, but with less margin. A gearbox reduces the load inertia seen by the motor by the square of the ratio.<\/p>\n<ol class=\"g-pit\">\n<li><b>Choosing the motor by power.<\/b> Peak torque, RMS torque and inertia ratio decide, not kW.<\/li>\n<li><b>Mechanics that are too flexible.<\/b> Long belts, gearbox backlash and weak mountings make the axis oscillate, however good the drive.<\/li>\n<li><b>Using the holding brake to stop.<\/b> The brake is for holding the load at standstill. Used to stop a moving load, it wears quickly.<\/li>\n<li><b>Poor cabling.<\/b> Motor and encoder cables must be shielded, routed away from signal cables and rated for cable chains if the axis moves.<\/li>\n<\/ol>\n<h2>Control and safety functions<\/h2>\n<p>Analogue \u00b110 V and pulse train control have largely given way to deterministic networks, where the motion controller synchronises many axes with cycle times below one millisecond:<\/p>\n<ul>\n<li><b>EtherCAT<\/b> \u2013 open and widespread. The CiA 402 drive profile makes it easier to mix brands, and safety signals can share the network with FSoE (Safety over EtherCAT).<\/li>\n<li><b>MECHATROLINK-III<\/b> \u2013 the motion network developed by Yaskawa, easy to configure with Yaskawa controllers.<\/li>\n<li><b>PROFINET<\/b> \u2013 common in Siemens environments, with the PROFIdrive profile and PROFIsafe for safety functions.<\/li>\n<\/ul>\n<p>Motion is often programmed with PLCopen Motion Control function blocks in IEC 61131-3, for example for electronic cams, electronic gearing and flying shears.<\/p>\n<p>Safety functions for drives are defined in IEC 61800-5-2. <b>STO (Safe Torque Off)<\/b> removes torque immediately and corresponds to stop category 0 in IEC 60204-1. <b>SS1 (Safe Stop 1)<\/b> decelerates the motor in a controlled way and then activates STO, corresponding to stop category 1. Safety modules add <b>SBC<\/b> for safe holding brake control and <b>SLS<\/b> for safely limited speed during setup and troubleshooting. The required level, PL to ISO 13849-1 or SIL to IEC 62061, follows from the machine risk assessment.<\/p>\n<h2>Where are servo systems used?<\/h2>\n<ul>\n<li><b>Packaging and food<\/b> \u2013 flow wrappers, labelling, filling and pick-and-place with several synchronised axes.<\/li>\n<li><b>Robots and handling<\/b> \u2013 industrial robots, gantry robots and automated guided vehicles (AGVs).<\/li>\n<li><b>Machine tools<\/b> \u2013 feed axes in CNC milling machines, lathes and laser cutters.<\/li>\n<li><b>Presses and sheet metal<\/b> \u2013 servo presses with a programmable stroke profile and sheet metal feeders.<\/li>\n<li><b>Semiconductors and electronics<\/b> \u2013 wafer handling, component placement and inspection with linear and direct drive motors.<\/li>\n<li><b>Medical and laboratory<\/b> \u2013 sample handling and pipetting robots.<\/li>\n<\/ul>\n<h2>Servo systems from SCN<\/h2>\n<p>We offer servo systems from Yaskawa: servo motors and servo drives in the Sigma-7 and Sigma-X series, linear motors, direct drive motors and motion controllers for up to 64 axes. Tell us about the motion, the load and the control system, and we will help you size the axis.<\/p>\n<h3>Examples from our range<\/h3>\n<div class=\"g-prod\"><a class=\"g-pc\" href=\"https:\/\/scn.eu\/en\/product\/sgmxa-sigma-x-servo-motor\/\"><img loading=\"lazy\" src=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/yaskawa-sgmxa-main.webp\" alt=\"Yaskawa SGMXA Sigma-X Servo Motor\" width=\"800\" height=\"800\" loading=\"lazy\" decoding=\"async\"><span class=\"g-pb\">Yaskawa<\/span><span class=\"g-pn\">SGMXA Sigma-X Servo Motor<\/span><span class=\"g-pw\">Servo motor from 50 W to 5 kW with a 26-bit absolute encoder, up to 7,000 rpm and IP67.<\/span><\/a><a class=\"g-pc\" href=\"https:\/\/scn.eu\/en\/product\/sgdxs-sigma-x-single-axis-servo-drive\/\"><img loading=\"lazy\" src=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/yaskawa-sgdxs-main.webp\" alt=\"Yaskawa SGDXS Sigma-X Single-Axis Servo Drive\" width=\"800\" height=\"800\" loading=\"lazy\" decoding=\"async\"><span class=\"g-pb\">Yaskawa<\/span><span class=\"g-pn\">SGDXS Sigma-X Single-Axis Servo Drive<\/span><span class=\"g-pw\">Single-axis servo drive, 50 W to 15 kW, for rotary, linear and direct drive motors. Controlled over EtherCAT.<\/span><\/a><a class=\"g-pc\" href=\"https:\/\/scn.eu\/en\/product\/icube-control-machine-controller\/\"><img loading=\"lazy\" src=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/yaskawa-icube-control-main.webp\" alt=\"Yaskawa iCube Control Machine Controller\" width=\"800\" height=\"800\" loading=\"lazy\" decoding=\"async\"><span class=\"g-pb\">Yaskawa<\/span><span class=\"g-pn\">iCube Control Machine Controller<\/span><span class=\"g-pw\">PLCnext-based machine controller with EtherCAT master for up to 64 axes and FSoE for safety functions.<\/span><\/a><\/div>\n<div class=\"g-links\"><a href=\"https:\/\/scn.eu\/en\/product-category\/products\/drives-and-motion\/servo-motors\/\">Servo motors<\/a><a href=\"https:\/\/scn.eu\/en\/product-category\/products\/drives-and-motion\/servo-motors\/servo-pack\/\">Servo drives (Servopack)<\/a><a href=\"https:\/\/scn.eu\/en\/product-category\/products\/drives-and-motion\/servo-motors\/motion-controllers\/\">Motion controllers<\/a><a href=\"https:\/\/scn.eu\/en\/product-category\/products\/drives-and-motion\/\">Drives and motion<\/a><a href=\"https:\/\/scn.eu\/en\/product-category\/products\/sensors\/absolute-encoders\/\">Absolute rotary encoders<\/a><\/div>\n<div class=\"g-cta\">\n<p>Building a new axis or replacing an older servo system? Ask one of our engineers \u2013 you get an answer within 24 hours.<\/p>\n<p><a href=\"https:\/\/scn.eu\/en\/contact\/\">Ask an engineer<\/a><\/div>\n<h2>Frequently asked questions<\/h2>\n<details>\n<summary>What is the difference between a servo motor and a standard motor?<\/summary>\n<p>A servo motor is built for fast acceleration and precise positioning and always has an encoder. A standard induction motor is built for steady speed over long periods.<\/p>\n<\/details>\n<details>\n<summary>What does a servo drive do?<\/summary>\n<p>It powers the motor and controls position, speed and torque based on the encoder signal. It is also called a servo amplifier, and SERVOPACK at Yaskawa.<\/p>\n<\/details>\n<details>\n<summary>What is inertia ratio?<\/summary>\n<p>The ratio between the load inertia, referred to the motor shaft, and the motor\u2019s own inertia. A low ratio, often below 10:1, gives a faster and more stable axis.<\/p>\n<\/details>\n<details>\n<summary>Can I mix a servo motor and servo drive from different makers?<\/summary>\n<p>Sometimes, but the drive must support the motor encoder and motor data. The simplest choice is a motor and drive from the same series.<\/p>\n<\/details>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>A servo system moves a load to the right position, at the right speed and at the right time \u2013 over and over again. Here is how motor, servo drive and encoder work together, how to size an axis and when servo is the right choice.<\/p>\n","protected":false},"author":11,"featured_media":8234463,"template":"","meta":{"_yoast_wpseo_focuskw":"servo motor","_yoast_wpseo_metadesc":"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.","_kad_post_transparent":"","_kad_post_title":"hide","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"hide","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","_scn_guide_cats":[909,915,914],"_scn_guide_sectors":[1011],"_scn_guide_type":"tech","_scn_guide_order":42,"footnotes":""},"class_list":["post-8234495","scn_guide","type-scn_guide","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Servo motors and servo drives \u2013 how servo systems work | SCN<\/title>\n<meta name=\"description\" content=\"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/scn.eu\/en\/guides\/servo-motors\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Servo motors and servo drives \u2013 how servo systems work | SCN\" \/>\n<meta property=\"og:description\" content=\"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/scn.eu\/en\/guides\/servo-motors\/\" \/>\n<meta property=\"og:site_name\" content=\"SCN\" \/>\n<meta property=\"og:image\" content=\"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp\" \/>\n\t<meta property=\"og:image:width\" content=\"1520\" \/>\n\t<meta property=\"og:image:height\" content=\"488\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/webp\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"7 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/\",\"url\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/\",\"name\":\"Servo motors and servo drives \u2013 how servo systems work | SCN\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/#primaryimage\"},\"image\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/#primaryimage\"},\"thumbnailUrl\":\"https:\\\/\\\/scn.eu\\\/wp-content\\\/uploads\\\/2026\\\/10\\\/scn-guide-servo-f1-en.webp\",\"datePublished\":\"2026-10-24T17:31:54+00:00\",\"description\":\"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/#primaryimage\",\"url\":\"https:\\\/\\\/scn.eu\\\/wp-content\\\/uploads\\\/2026\\\/10\\\/scn-guide-servo-f1-en.webp\",\"contentUrl\":\"https:\\\/\\\/scn.eu\\\/wp-content\\\/uploads\\\/2026\\\/10\\\/scn-guide-servo-f1-en.webp\",\"width\":1520,\"height\":488,\"caption\":\"Control loop: the motion controller sends commands to the servo drive, which controls position, speed and current to the servo motor. The encoder feeds back position and speed.\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/guides\\\/servo-motors\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/scn.eu\\\/en\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Servo motors and servo drives \u2013 how servo systems work\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#website\",\"url\":\"https:\\\/\\\/scn.eu\\\/en\\\/\",\"name\":\"SCN\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/scn.eu\\\/en\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#organization\",\"name\":\"Sensor Control Nordic\",\"alternateName\":\"SCN\",\"url\":\"https:\\\/\\\/scn.eu\\\/en\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/scn.eu\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/SCN-logo-scaled.png\",\"contentUrl\":\"https:\\\/\\\/scn.eu\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/SCN-logo-scaled.png\",\"width\":2560,\"height\":632,\"caption\":\"Sensor Control Nordic\"},\"image\":{\"@id\":\"https:\\\/\\\/scn.eu\\\/en\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.linkedin.com\\\/company\\\/sensor-control-nordic-ab\"],\"location\":[{\"@type\":\"Place\",\"name\":\"SCN Walsall\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"46 Hall Lane, Walsall Wood\",\"addressLocality\":\"Walsall\",\"postalCode\":\"WS9 9DP\",\"addressCountry\":\"GB\",\"addressRegion\":\"West Midlands\"},\"telephone\":\"+44 1634 300 900\"},{\"@type\":\"Place\",\"name\":\"SCN Stockholm\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Gustav III:s Boulevard 32\",\"addressLocality\":\"Solna\",\"postalCode\":\"169 73\",\"addressCountry\":\"SE\"},\"telephone\":\"+46 8 668 21 00\"},{\"@type\":\"Place\",\"name\":\"SCN Malm\u00f6\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"R\u00f6nnviksgatan 13\",\"addressLocality\":\"Malm\u00f6\",\"postalCode\":\"213 74\",\"addressCountry\":\"SE\"},\"telephone\":\"+46 40 688 02 00\"},{\"@type\":\"Place\",\"name\":\"SCN Sundsvall\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Trafikgatan 11\",\"addressLocality\":\"Sundsvall\",\"postalCode\":\"856 44\",\"addressCountry\":\"SE\"},\"telephone\":\"+46 60 740 75 81\"},{\"@type\":\"Place\",\"name\":\"SCN Helsinki\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Huopalahdentie 24A\",\"addressLocality\":\"Helsinki\",\"postalCode\":\"00350\",\"addressCountry\":\"FI\"},\"telephone\":\"+358 20 734 8600\"},{\"@type\":\"Place\",\"name\":\"SCN Tallinn\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Narva mnt 5\",\"addressLocality\":\"Tallinn\",\"postalCode\":\"10117\",\"addressCountry\":\"EE\"},\"telephone\":\"+372 651 4550\"},{\"@type\":\"Place\",\"name\":\"SCN Oslo\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Kristoffer Robins vei 13\",\"addressLocality\":\"Oslo\",\"postalCode\":\"0978\",\"addressCountry\":\"NO\"},\"telephone\":\"+47 23 88 89 62\"},{\"@type\":\"Place\",\"name\":\"SCN R\u00f8dekro\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"H\u00e6rvejen 8\",\"addressLocality\":\"R\u00f8dekro\",\"postalCode\":\"6230\",\"addressCountry\":\"DK\"},\"telephone\":\"+45 78 74 65 00\"},{\"@type\":\"Place\",\"name\":\"SCN Madrid\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"Paseo de la Castellana, 200\",\"addressLocality\":\"Madrid\",\"postalCode\":\"28046\",\"addressCountry\":\"ES\",\"addressRegion\":\"Comunidad de Madrid\"},\"telephone\":\"+34 93 641 59 97\"},{\"@type\":\"Place\",\"name\":\"SCN Tarnowskie G\u00f3ry\",\"address\":{\"@type\":\"PostalAddress\",\"streetAddress\":\"ul. Ma\u0142a 1B\",\"addressLocality\":\"Tarnowskie G\u00f3ry\",\"postalCode\":\"42-605\",\"addressCountry\":\"PL\"},\"telephone\":\"+48 511 199 460\"}],\"email\":\"sales@scn.eu\",\"areaServed\":[\"SE\",\"NO\",\"DK\",\"FI\",\"EE\",\"GB\",\"PL\",\"ES\"],\"knowsLanguage\":[\"en\",\"sv\",\"da\",\"fi\",\"nb\",\"et\",\"pl\",\"es\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Servo motors and servo drives \u2013 how servo systems work | SCN","description":"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/scn.eu\/en\/guides\/servo-motors\/","og_locale":"en_US","og_type":"article","og_title":"Servo motors and servo drives \u2013 how servo systems work | SCN","og_description":"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.","og_url":"https:\/\/scn.eu\/en\/guides\/servo-motors\/","og_site_name":"SCN","og_image":[{"width":1520,"height":488,"url":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp","type":"image\/webp"}],"twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"7 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/","url":"https:\/\/scn.eu\/en\/guides\/servo-motors\/","name":"Servo motors and servo drives \u2013 how servo systems work | SCN","isPartOf":{"@id":"https:\/\/scn.eu\/en\/#website"},"primaryImageOfPage":{"@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/#primaryimage"},"image":{"@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/#primaryimage"},"thumbnailUrl":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp","datePublished":"2026-10-24T17:31:54+00:00","description":"How servo motors and servo drives work: feedback, servo vs VFD and stepper, sizing, inertia ratio, EtherCAT and STO. A practical guide from SCN.","breadcrumb":{"@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/scn.eu\/en\/guides\/servo-motors\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/#primaryimage","url":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp","contentUrl":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/10\/scn-guide-servo-f1-en.webp","width":1520,"height":488,"caption":"Control loop: the motion controller sends commands to the servo drive, which controls position, speed and current to the servo motor. The encoder feeds back position and speed."},{"@type":"BreadcrumbList","@id":"https:\/\/scn.eu\/en\/guides\/servo-motors\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/scn.eu\/en\/"},{"@type":"ListItem","position":2,"name":"Servo motors and servo drives \u2013 how servo systems work"}]},{"@type":"WebSite","@id":"https:\/\/scn.eu\/en\/#website","url":"https:\/\/scn.eu\/en\/","name":"SCN","description":"","publisher":{"@id":"https:\/\/scn.eu\/en\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/scn.eu\/en\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/scn.eu\/en\/#organization","name":"Sensor Control Nordic","alternateName":"SCN","url":"https:\/\/scn.eu\/en\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/scn.eu\/en\/#\/schema\/logo\/image\/","url":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/04\/SCN-logo-scaled.png","contentUrl":"https:\/\/scn.eu\/wp-content\/uploads\/2026\/04\/SCN-logo-scaled.png","width":2560,"height":632,"caption":"Sensor Control Nordic"},"image":{"@id":"https:\/\/scn.eu\/en\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.linkedin.com\/company\/sensor-control-nordic-ab"],"location":[{"@type":"Place","name":"SCN Walsall","address":{"@type":"PostalAddress","streetAddress":"46 Hall Lane, Walsall Wood","addressLocality":"Walsall","postalCode":"WS9 9DP","addressCountry":"GB","addressRegion":"West Midlands"},"telephone":"+44 1634 300 900"},{"@type":"Place","name":"SCN Stockholm","address":{"@type":"PostalAddress","streetAddress":"Gustav III:s Boulevard 32","addressLocality":"Solna","postalCode":"169 73","addressCountry":"SE"},"telephone":"+46 8 668 21 00"},{"@type":"Place","name":"SCN Malm\u00f6","address":{"@type":"PostalAddress","streetAddress":"R\u00f6nnviksgatan 13","addressLocality":"Malm\u00f6","postalCode":"213 74","addressCountry":"SE"},"telephone":"+46 40 688 02 00"},{"@type":"Place","name":"SCN Sundsvall","address":{"@type":"PostalAddress","streetAddress":"Trafikgatan 11","addressLocality":"Sundsvall","postalCode":"856 44","addressCountry":"SE"},"telephone":"+46 60 740 75 81"},{"@type":"Place","name":"SCN Helsinki","address":{"@type":"PostalAddress","streetAddress":"Huopalahdentie 24A","addressLocality":"Helsinki","postalCode":"00350","addressCountry":"FI"},"telephone":"+358 20 734 8600"},{"@type":"Place","name":"SCN Tallinn","address":{"@type":"PostalAddress","streetAddress":"Narva mnt 5","addressLocality":"Tallinn","postalCode":"10117","addressCountry":"EE"},"telephone":"+372 651 4550"},{"@type":"Place","name":"SCN Oslo","address":{"@type":"PostalAddress","streetAddress":"Kristoffer Robins vei 13","addressLocality":"Oslo","postalCode":"0978","addressCountry":"NO"},"telephone":"+47 23 88 89 62"},{"@type":"Place","name":"SCN R\u00f8dekro","address":{"@type":"PostalAddress","streetAddress":"H\u00e6rvejen 8","addressLocality":"R\u00f8dekro","postalCode":"6230","addressCountry":"DK"},"telephone":"+45 78 74 65 00"},{"@type":"Place","name":"SCN Madrid","address":{"@type":"PostalAddress","streetAddress":"Paseo de la Castellana, 200","addressLocality":"Madrid","postalCode":"28046","addressCountry":"ES","addressRegion":"Comunidad de Madrid"},"telephone":"+34 93 641 59 97"},{"@type":"Place","name":"SCN Tarnowskie G\u00f3ry","address":{"@type":"PostalAddress","streetAddress":"ul. Ma\u0142a 1B","addressLocality":"Tarnowskie G\u00f3ry","postalCode":"42-605","addressCountry":"PL"},"telephone":"+48 511 199 460"}],"email":"sales@scn.eu","areaServed":["SE","NO","DK","FI","EE","GB","PL","ES"],"knowsLanguage":["en","sv","da","fi","nb","et","pl","es"]}]}},"_links":{"self":[{"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/scn_guide\/8234495","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/scn_guide"}],"about":[{"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/types\/scn_guide"}],"author":[{"embeddable":true,"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/users\/11"}],"version-history":[{"count":1,"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/scn_guide\/8234495\/revisions"}],"predecessor-version":[{"id":8234502,"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/scn_guide\/8234495\/revisions\/8234502"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/media\/8234463"}],"wp:attachment":[{"href":"https:\/\/scn.eu\/en\/wp-json\/wp\/v2\/media?parent=8234495"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}