{"id":481,"date":"2026-09-29T03:10:53","date_gmt":"2026-09-28T19:10:53","guid":{"rendered":"http:\/\/www.amico-in-affitto.com\/blog\/?p=481"},"modified":"2026-09-29T03:10:53","modified_gmt":"2026-09-28T19:10:53","slug":"how-do-i-set-up-the-automatic-restart-function-on-unidrive-sp-series-high-power-industri-4d46-d9bb78","status":"publish","type":"post","link":"http:\/\/www.amico-in-affitto.com\/blog\/2026\/09\/29\/how-do-i-set-up-the-automatic-restart-function-on-unidrive-sp-series-high-power-industri-4d46-d9bb78\/","title":{"rendered":"How do I set up the automatic restart function on Unidrive SP Series High Power Industrial VFDs?"},"content":{"rendered":"

As a supplier specializing in Unidrive SP Series High Power Industrial Variable Frequency Drives (VFDs), I\u2019ve lost count of how many times I\u2019ve fielded questions from plant managers, maintenance technicians, and electrical engineers asking about setting up automatic restart on these workhorses. Let\u2019s be real\u2014industrial operations don\u2019t stop for power blips or momentary overloads, and a single unexpected shutdown can cost thousands, even millions, in lost production, scrap material, and missed deadlines. The Unidrive SP Series is built to handle the toughest applications, from heavy conveyor systems to pump stations in mining, oil and gas, and manufacturing, and its automatic restart function is one of its most underutilized, game-changing features. Today, I\u2019m breaking down exactly how to set this up, with hands-on tips I\u2019ve picked up supporting clients across North America and Europe over the past eight years. Unidrive SP Series High Power Industrial VFDs<\/a><\/p>\n

<\/p>\n

First, let\u2019s get clear on what automatic restart on the Unidrive SP actually does (and what it doesn\u2019t do). This isn\u2019t a \u201cset it and forget it\u201d magic button that will kick the VFD back on no matter what. It\u2019s a protective feature designed for specific fault scenarios: temporary power dips, short-term overcurrent trips from a motor jamming temporarily, or momentary supply glitches that don\u2019t cause permanent damage to the VFD or the connected equipment. It will not, however, restart after a catastrophic fault\u2014like an overheating motor that\u2019s seized, a VFD internal component failure, or a phase loss that\u2019s long enough to risk damage. Getting this distinction right is critical to avoiding unnecessary trips that could cause secondary harm to your process.<\/p>\n

Before you touch any parameters, a quick safety check is non-negotiable. I always remind technicians to lock out and tag out (LOTO) the VFD\u2019s main power supply, even if you\u2019re only adjusting control settings. The Unidrive SP\u2019s control terminal is low-voltage, but the power bus inside the drive can hold a lethal charge for minutes after the supply is disconnected. If you\u2019re working on a VFD mounted on a high conveyor or a pump that\u2019s elevated, make sure the equipment is secured so it can\u2019t move unexpectedly when you re-energize the drive later. I once had a client skip this step during a test, and the conveyor lurched forward mid-adjustment, nearly hitting a technician. Don\u2019t be that person.<\/p>\n

Now, let\u2019s dive into the step-by-step setup, starting with the menu structure. The Unidrive SP uses its standard keypad (or the software tools like DriveTools SP, which I always recommend for larger installations) to access parameters. For this guide, I\u2019ll cover both keypad and DriveTools SP methods, since many of my clients prefer on-site keypad adjustments for quick jobs and DriveTools for bulk configuration.<\/p>\n

First, access the main parameter menu. On the physical keypad, press the \u201cMenu\u201d button until you reach the \u201cFault Management\u201d folder\u2014this is where all restart-related settings live. If you\u2019re using DriveTools SP, connect your laptop to the drive via the USB or Ethernet port, pull up the device tree, and select \u201cFault Settings\u201d from the left-hand menu. That\u2019s the easy part.<\/p>\n

Next, locate the automatic restart enable parameter. On the Unidrive SP, this is parameter 10.03, labeled \u201cAuto Restart Enable.\u201d By default, this is set to \u201c0\u201d (Disabled) from the factory, which makes sense for most new installations where technicians want to test the drive first before enabling automatic restarts. To turn it on, set this parameter to \u201c1\u201d for \u201cEnabled (Standard)\u201d mode. Wait\u2014there\u2019s a second mode here, parameter 10.03 set to \u201c2\u201d which is \u201cEnabled (Coast)\u201d mode. I almost never recommend Coast mode for high-power applications, because it lets the motor coast to a stop, which can be dangerous for large, inertia-heavy loads. Standard mode uses the VFD\u2019s speed tracking algorithm to match the motor\u2019s actual speed when power is restored, so it ramps the motor back up smoothly without overcurrent. That\u2019s the setting you want for most industrial uses.<\/p>\n

Once auto restart is enabled, you need to set the number of allowed restart attempts, because you don\u2019t want the drive to keep trying to restart a faulty machine over and over. That\u2019s parameter 10.04, \u201cNumber of Auto Restart Attempts.\u201d The factory default is 3, which works well for most applications\u2014one or two attempts to clear a temporary glitch, then a full fault trip if it fails. For a critical pump system that can\u2019t go down, some of my clients set this to 5, but I advise against going higher than that. Each additional attempt puts more wear on the motor windings and VFD output transistors, and if it\u2019s a permanent fault, you\u2019re just wasting production time. I recently had a paper mill client that set this to 10 after a series of minor trips, and it ended up burning out a motor winding after three failed restarts because the heat from repeated attempts was too much. Stick to 2-5, depending on your load.<\/p>\n

Then, set the delay time between restart attempts. Parameter 10.05, \u201cAuto Restart Delay,\u201d controls how long the drive waits after a fault before attempting to restart. For most high-power applications, set this between 5 and 15 seconds. Why? The delay gives the motor time to cool down if it overheated during the trip, and gives the plant\u2019s power grid time to stabilize if it was a grid glitch. For conveyor systems with heavy loads, I go with 10 seconds\u2014enough time for the conveyor to come to a complete, safe stop, and for the VFD\u2019s internal systems to reset. For smaller pumps, 5 seconds works, but I always test this setting on-site. Last quarter, I worked with a water treatment plant that set their delay to 2 seconds after a minor trip, and the motor tried to restart while still hot, tripping again immediately, creating a loop that caused more downtime than if they\u2019d just had a single fault trip.<\/p>\n

The final critical parameter for automatic restart is parameter 10.06, \u201cSpeed Tracking Mode.\u201d This is what makes the Standard auto restart mode work safely. Set this to \u201c1\u201d for \u201cFull Speed Tracking\u201d for all high-power applications. Full speed tracking uses the VFD\u2019s built-in encoderless speed control (or an optional encoder, if you have one installed) to detect the motor\u2019s actual speed when power is restored, so it doesn\u2019t apply full voltage to a stationary motor, which would cause a massive inrush current that can trip the drive\u2019s overload protection or even damage the motor. For applications with very high inertia loads\u2014like large centrifuges or kilns\u2014you might set this to \u201c2\u201d for \u201cInertia Speed Tracking,\u201d which is optimized for loads that take a long time to spin down. Never leave this set to \u201c0\u201d (Disabled), which would make the VFD start the motor from zero speed, causing the inrush current I just mentioned.<\/p>\n

Now, if you\u2019re using DriveTools SP instead of the physical keypad, the steps are almost identical, but you\u2019ll have additional visibility into the settings. DriveTools lets you simulate faults and test the automatic restart function before you put the drive online, which is a huge time-saver for large installations. I always recommend clients run a test using the \u201cFault Simulation\u201d tool in DriveTools before commissioning a new drive. You can trigger a temporary overcurrent fault, then watch the drive\u2019s parameter 10.07, \u201cAuto Restart Status,\u201d to confirm it\u2019s counting down the delay, tracking speed, and attempting to restart. This also lets you adjust the number of attempts or delay time before the drive goes into a permanent fault, so you don\u2019t have to climb up to the drive\u2019s panel to make changes after it\u2019s installed.<\/p>\n

But here\u2019s the part most guides don\u2019t tell you: common pitfalls to avoid when setting up auto restart on the Unidrive SP. First, make sure your fault conditions are configured correctly. Parameter 10.08, \u201cAuto Restart Fault Mask,\u201d lets you select which faults trigger an automatic restart. The factory default includes overcurrent, overvoltage, undervoltage, and motor thermal faults, which is correct for most applications. But if you accidentally remove a fault from the mask\u2014like a phase loss fault\u2014the drive won\u2019t restart if you have a phase glitch, which defeats the purpose of the feature. Conversely, don\u2019t add faults that shouldn\u2019t trigger a restart, like a drive over-temperature fault, which would be dangerous to ignore. If the drive itself is overheating, it should trip permanently, not restart, to prevent internal damage.<\/p>\n

Another pitfall: not accounting for your control system. If the Unidrive SP is connected to a PLC or a plant-wide control system, make sure the PLC is programmed to acknowledge the auto restart event. Some older PLCs will flag the VFD\u2019s restart as a \u201cuncontrolled start\u201d if they\u2019re not set up to monitor drive status, which can cause safety alarms or even trigger a plant-wide stop. I always work with the client\u2019s control engineer to coordinate the auto restart settings between the VFD and the PLC, so both systems are on the same page. For example, we set the PLC to receive a signal when the drive is attempting an auto restart, so it can adjust downstream processes if needed, like slowing a conveyor\u2019s feed rate temporarily.<\/p>\n

Testing is the most important step. I always tell clients to run three different tests after setting up auto restart: a minor glitch test, a temporary overload test, and a failed fault test. For the minor glitch test, temporarily cut power to the VFD for 5 seconds, then restore it. Watch to see if the drive ramps the motor back up smoothly without tripping. For the temporary overload test, simulate a small overload (many Unidrive SP models have an overload test function) to trigger a fault, then confirm the drive attempts to restart the set number of times before tripping permanently. For the failed fault test, trigger a real fault\u2014like disconnecting a motor phase\u2014to make sure the drive trips permanently and doesn\u2019t keep trying to restart a faulty load. I once had a client that skipped these tests and had the auto restart setting enabled on a pump that had a seized impeller, leading to three failed restarts that burned out the VFD\u2019s output module. A 15-minute test would have caught that before it cost them $12,000 in repairs.<\/p>\n

For high-power Unidrive SP drives (100HP and above, which are the most common in heavy industry), there are a few additional considerations. First, make sure the motor\u2019s thermal protection is properly calibrated. The Unidrive SP\u2019s motor thermal model is parameter 4.01, \u201cMotor Thermal Time Constant,\u201d which should be set to match your specific motor. If this is incorrect, the drive might trip for a minor thermal blip and not attempt a restart, or it might restart before the motor cools down, leading to overheating. I always provide clients with a copy of the motor\u2019s spec sheet to calibrate this parameter accurately\u2014something many suppliers skip, but it\u2019s critical for reliable auto restart.<\/p>\n

Second, for drives connected to 480V or 600V three-phase power lines, make sure the line impedance is within the Unidrive SP\u2019s specifications. If the line is too high impedance, voltage dips during a fault recovery can be severe, which might cause the drive to abort the restart attempt. The Unidrive SP\u2019s automatic restart function includes a line voltage check, but it\u2019s better to confirm line impedance during installation, which I can help with as your supplier\u2014we offer free pre-installation assessments for high-power drive installations to avoid these kinds of issues.<\/p>\n

Now, let\u2019s talk about when auto restart is not the right choice. This feature isn\u2019t for every application. If you\u2019re running a packaging line where an unexpected restart could crush products or injure workers, disable auto restart and use a manual reset instead. For applications with sensitive equipment, like precision machining or medical production, a sudden restart could ruin parts or quality. But for the majority of high-power industrial applications where uptime is critical\u2014conveyors, pumps, fans, compressors\u2014auto restart on the Unidrive SP is a must-have.<\/p>\n

<\/p>\n

As a supplier, my goal isn\u2019t just to sell you a Unidrive SP drive\u2014it\u2019s to make sure you get the most out of it. I\u2019ve worked with facilities that were running their Unidrive SP drives with auto restart disabled for years, not knowing what the feature could do for their downtime. One of my mining clients in Western Canada told me after setting up auto restart on their 500HP conveyor drives that they reduced unplanned downtime by 22% in the first quarter. That\u2019s thousands of tons of ore moved, thousands of dollars in additional revenue, all from a few parameter settings.<\/p>\n

B&R<\/a> If you have a Unidrive SP Series High Power Industrial VFD and you\u2019re looking to set up automatic restart, or if you need help with calibration, testing, or troubleshooting, I\u2019m here to assist. Every installation is different, and I don\u2019t believe in one-size-fits-all settings\u2014we can work together to adjust the parameters to fit your specific load, safety requirements, and production needs. Don\u2019t let a minor power glitch or temporary overload cost you critical production time. Reach out to us to discuss your automatic restart setup, and we can walk you through every step, from initial configuration to on-site testing.<\/p>\n

References<\/h3>\n
    \n
  1. Control Techniques Unidrive SP Series Technical Manual, Revision 7.0, 2022<\/li>\n
  2. Unidrive SP DriveTools SP Software User Guide, 2021<\/li>\n
  3. Industrial Variable Frequency Drive Best Practices for Uptime, International Electrotechnical Commission (IEC) Standard 61800-5-1, 2019<\/li>\n<\/ol>\n
    \n

    Yuntengbao Automation (Xiamen) Co., Ltd.<\/a><\/p>\n

    Address: Room 013, 4th Floor, No. 606-4, Xinglong Road, Huli District, Xiamen City, Fujian Province, China
    E-mail: lrene@plcsupplychain.com
    WebSite:     https:\/\/www.plcsupplychain.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

    As a supplier specializing in Unidrive SP Series High Power Industrial Variable Frequency Drives (VFDs), I\u2019ve … How do I set up the automatic restart function on Unidrive SP Series High Power Industrial VFDs?<\/span>Read more<\/a><\/p>\n","protected":false},"author":25,"featured_media":481,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[444],"class_list":["post-481","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry","tag-unidrive-sp-series-high-power-industrial-vfds-4234-d9f72b"],"_links":{"self":[{"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/posts\/481","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/users\/25"}],"replies":[{"embeddable":true,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/comments?post=481"}],"version-history":[{"count":0,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/posts\/481\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/posts\/481"}],"wp:attachment":[{"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/media?parent=481"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/categories?post=481"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.amico-in-affitto.com\/blog\/wp-json\/wp\/v2\/tags?post=481"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}