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[ { "title": "LEARN | Motor Protection Pt 5 \u2013 Coordinated Motor Starters", "nid": "604", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/contactus.html\u0022\u003E\u003Cimg alt=\u0022Motor Protection pt 5\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022db079057-2c20-4ac3-813c-277162e760a7\u0022 height=\u0022252\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Motors%20-newsletter%20image%205.jpg\u0022 width=\u0022503\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EWhen it comes to downtime, motors are a disproportionally large contributor compared to other causes, simply because motors are used in so many processes, from pumping to material management. So, a failure in a motor will have a serious ripple effect on productivity.\u003C/p\u003E\n\u003Cp\u003EWe\u2019re wrapping up our series on Motor Protection. Before we get into the fifth and final instalment, take a moment to catch up on previous articles in the series\u2026\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-Pt-1--The-importance-of-Motor-Protection\u0022\u003E\u003Cstrong\u003EPart 1\u00A0\u00A0 \u00A0- \u003C/strong\u003Ethe importance of motor protection\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-2--Circuit-Breakers-vs-Fuses\u0022\u003E\u003Cstrong\u003EPart 2\u003C/strong\u003E\u00A0\u00A0\u00A0 - fuses vs circuit breakers\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-3--Considering-MPCBs\u0022\u003E\u003Cstrong\u003EPart 3\u003C/strong\u003E\u00A0\u00A0\u00A0 - Motor Protection Circuit Breakers (MPCBs)\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-4--Motor-Circuit-Breakers\u0022\u003E\u003Cstrong\u003EPart 4\u003C/strong\u003E\u00A0\u00A0\u00A0 - Motor Circuit Breakers\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EIn the fifth instalment, we tackle coordinated motor starters...\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EHow do motors fail?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe most common failure mode for a motor is when it is under excessive load. Such a condition causes an increased draw of current, which then causes overheating. It\u2019s this overheating that causes the undue wear on motor components that ultimately results in failure.\u003C/p\u003E\n\u003Cp\u003EHowever, its short circuits in motors that pose the greatest dangers for the equipment, the installation, and for personnel. There are a few possible sources, but any short circuit can cause a sudden and massive surge of current within milliseconds that can melt and destroy contacts, produce electrical arcs and even explosions. Short circuits can not only cause physical damage \u2013 they can easily lead to catastrophic fires. In fact, it\u2019s estimated that\u00A060% of fires\u00A0are due to short circuits.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EStandards that address motor short circuits\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe International Electro-technical Commission (IEC) has recognized that electrical faults in motor control are a critical situation that needs to be properly addressed to ensure safety of personnel and equipment, as well as productivity of an installation. Therefore, the IEC has developed specific standards and testing procedures to ensure that the combination of devices used to control motors \u2013 i.e. motor starters \u2013 is safe. This is achieved through\u00A0\u003Cem\u003E\u201Ccoordination\u201D\u003C/em\u003E.\u003C/p\u003E\n\u003Cp\u003EA \u2018coordinated starter\u2019 is a tested combination of short circuit protection devices (e.g. fuses or circuit breakers), switching devices, and overload protection devices. The motor starter combination is tested under extreme conditions and is required to clear the fault quickly, without damage to the installation or risk to the operator. This makes it the optimum, tested combination of devices to ensure safety.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EThere are two types of coordination included in the\u00A0\u003C/strong\u003EIEC 60947-4-1\u00A0\u003Cstrong\u003Estandard: Type I and Type II. There is also an additional level of coordination specified by IEC 60947-6-2, which Schneider Electric refers to as \u2018Total Coordination\u2019. Let\u2019s have a look at how each of these are defined.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp style=\u0022margin-left:18.0pt;\u0022\u003E1.\u003Cstrong\u003EType I Coordination.\u003C/strong\u003E\u00A0This coordination level provides a basic solution, which balances uptime and cost effectiveness. It\u2019s a good choice when machine uptime is not a priority, as this level does not provide continuity of service. Also, there are associated maintenance costs. Before restarting, replacement of the starter is recommended\u003C/p\u003E\n\u003Cp style=\u0022margin-left:18.0pt;\u0022\u003E2.\u003Cstrong\u003EType II Coordination.\u003C/strong\u003E\u00A0This is a high performance solution, providing reduced machine shutdown time and reduced cost of equipment replacement. The motor starter must be ready for reuse after a fault, with only a simple inspection required. Contacts may become welded but are easily separated.\u003C/p\u003E\n\u003Cp style=\u0022margin-left:18.0pt;\u0022\u003E\u003Cstrong\u003E3.Total Coordination.\u003C/strong\u003E\u00A0This is the highest possible performance, ideal for mission-critical operations and processes. There is no damage to the equipment, and following the fault the starter must be immediately reusable. No resetting is required, and no inspection is needed. Therefore, the installation can return immediately to operation. This level of coordination is listed under a different standard, as it is defined for combination devices with multiple functions.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EChoosing coordinated motor starters\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EYou can see that these levels of coordination enable a range of benefits, from protecting people and equipment, to permitting a greater continuity of service, to reducing maintenance costs by avoiding the time and cost of replacing equipment. Given the increasing costs of downtime and machine or process failures, it\u2019s clear that coordination of motor starters is moving from a choice to a necessity, as they deliver a tested, guaranteed solution.\u003C/p\u003E\n\u003Cp\u003ETo begin, you should first determine the level of coordination that suits your specific application and business requirements. Next, you should choose a manufacturer that has ensured that their motor starter complies with coordination standards. This requires testing the combination of components to the associated standard, and accordingly publishing the coordination tables for selection.\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-Pt-5--Coordinated-Motor-Starters\u0022\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E1.\u003Cstrong\u003E \u003Ca href=\u0022https://go.schneider-electric.com/ZA_202110_Schneider-Learning-Series-Webinar-Current-Limitation_On-Demand-ER-LP.html?source=Webinar\u0026amp;sDetail=Schneider-Learning-Series_ZA\u0022\u003EWATCH\u003C/a\u003E \u003C/strong\u003Ea webinar on Current Limitation\u003C/p\u003E\n\u003Cp\u003E2. \u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/ww/en/work/products/industrial-automation-control/tools/motor-control-configurator.jsp\u0022\u003EEXPLORE\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s EcoStruxure\u2122 Motor Control Starter Configurator\u003C/p\u003E\n\u003Cp\u003E3. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/contactus.html\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to us for a Schneider Electric solution for your facility\u003C/p\u003E\n\u003Cp\u003E4. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to receive these informative newsletters straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESource:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/machine-and-process-management/2018/11/15/coordinated-motor-starters-the-right-choice-for-reduced-downtime-and-increased-safety/\u0022\u003Ehttps://blog.se.com/machine-and-process-management/2018/11/15/coordinated-motor-starters-the-right-choice-for-reduced-downtime-and-increased-safety/\u003C/a\u003E\u003C/p\u003E\n", "created": "Jan 2022", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Motor Protection pt 4 \u2013 Motor Circuit Breakers", "nid": "603", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E\u003Cimg alt=\u0022Motors pt 4\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022e656ec7b-f760-47d3-9918-eebe13143a74\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Motors_-_newsletter_image_pt%204.jpg\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003EIn \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-Pt-1--The-importance-of-Motor-Protection\u0022\u003EPart 1\u003C/a\u003E \u003C/strong\u003Eof our series on Motor Protection, we outlined the importance of motor protection.\u003C/p\u003E\n\u003Cp\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-2--Circuit-Breakers-vs-Fuses\u0022\u003E\u003Cstrong\u003EPart 2\u003C/strong\u003E\u003C/a\u003E, we unpacked the major differences between fuses and circuit breakers, and posed a compelling argument as to why the latter should be preferred.\u003C/p\u003E\n\u003Cp\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-3--Considering-MPCBs\u0022\u003E\u003Cstrong\u003EPart 3\u003C/strong\u003E\u003C/a\u003E, we looked at four important reasons why you should specifically choose Motor Protection Circuit Breakers (MPCBs) for motor protection.\u003C/p\u003E\n\u003Cp\u003EWe continue to unpack motor protection in this fourth instalment of the series, by tackling motor circuit breakers.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EThe prevalence of motors in industries\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EIt\u2019s estimated that there are\u00A0more than 300 million electric motors in the world\u00A0being used in industry, infrastructure, and large buildings, with electric motor-driven systems (EMDS) accounting for between 43-46% of all global electricity consumption. Motors drive everything from processes, to commercial heating, ventilating, cooling, and refrigeration. With business productivity so dependent on them, it\u2019s important that they\u2019re properly protected.\u003C/p\u003E\n\u003Cp\u003EIn most jurisdictions, motor protection is mandatory, so OEM machine builders and electrical contractors will ensure that there is a circuit breaker used on each motor circuit. If the proper type of motor circuit breaker is selected, the motor will be adequately protected.\u003C/p\u003E\n\u003Cp\u003EUnfortunately, there are many examples in which a standard electrical distribution circuit breaker was chosen for this purpose. These breakers are typically selected because they are lower cost. But they are designed to protect standard types of circuits and loads, not motors. If such a breaker is used, there is a very high risk of motor damage, disruption and downtime for the end-customer, and fire.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EHere are five critical reasons behind why a dedicated motor circuit breaker should be used to protect a motor, not a distribution circuit breaker.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1.\u00A0\u00A0\u00A0 Risk of nuisance tripping during motor start-up\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EWhen a motor starts up, it draws current up to 10 times its rated value. This can last up to 30 seconds until it reaches its steady speed. Distribution circuit breakers typically have a magnetic threshold set at 8 times the rated current, or less. When current exceeds this threshold, the breaker identifies it as a short-circuit event on the distribution and trips immediately. For a motor, this type of overcurrent can simply represent regular starting up current. So you can see that a distribution circuit breaker used to protect a motor will very likely, and undesirably, trip when the motor starts up.\u003C/p\u003E\n\u003Cp\u003EIn contrast, dedicated motor circuit breakers are designed with their short-circuit trip threshold set much higher, usually 13 times the rated current. This avoids the risk of tripping during the motor start-up phase.\u003C/p\u003E\n\u003Cp\u003ETo save money while avoiding the risk of tripping on motor start-up, some contractors may select an overrated distribution circuit breaker, i.e. one with a higher threshold. Let\u2019s use the example of a 7.5 kW motor with 16 A rated current, and start-up current likely to reach 160 A. In this case, the contractor may choose a distribution circuit breaker rated at 25 A, with a magnetic threshold of around 200 A, so that motor start-up will not immediately trip the circuit breaker. However, there is the serious risk if the motor becomes overloaded during regular operation, reaching a current of up to 24 A, the 25 A rated breaker will not trip and the motor will be in serious risk of being destroyed after only a couple of minutes.\u003C/p\u003E\n\u003Cp\u003ENote that, in the next few years\u003Ca href=\u0022https://blog.se.com/machine-and-process-management/2014/05/14/high-efficiency-motors-european-directive-change-motor-starters-choice/\u0022\u003E, IE3/IE4 high-efficiency motors\u003C/a\u003E\u00A0will become mandatory in many regions. When using direct starters, these motors will have higher starting current that today\u2019s motor designs. This will make it even more important to choose the correct type of circuit breaker to protect these motors.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E2.\u00A0\u00A0\u00A0 Risk of nuisance tripping due to a transient overload\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EElectrical distribution circuit breakers are designed to protect cables. Their overload tripping times are set according to overcurrent withstand of cables, which is usually shorter than that of motors. So distribution breakers are likely to trip before the situation becomes dangerous for a motor. Keep in mind that motor protection relays, and dedicated motor electronic trip units, offer options to configure even slower overload protection for classes 10A, 10, 20, and 30.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3.\u00A0\u00A0\u00A0 Risk of nuisance tripping due to high ambient temperature\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EMost distribution circuit breakers are designed to operate under 30 \u00B0C, or in some cases under 40 \u00B0C. If ambient temperature exceeds this rating, the breaker will trip at a lower current than its rating, unnecessary interrupting a process.\u003C/p\u003E\n\u003Cp\u003EIn contrast, motor circuit breakers are set for operation under 60 \u00B0C, or optionally 65 \u00B0C. So, a 10 A rated motor circuit breaker, protecting a 10 A rated motor will not trip when current is 10 A and ambient temperature is 60 \u00B0C. In this way, machines and operations keep running while motors are still properly protected.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E4.\u00A0\u00A0\u00A0 Risk of motor damage due to a phase fault\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EA phase fault can happen for many reasons: wiring errors after maintenance, loose connections, a utility phase loss, or even motor aging. Distribution circuit breakers are not equipped to trip in case of phase unbalance or phase loss, as these common conditions pose no hazard to distribution networks. But a phase fault is a critical event for motors, causing mis-operation (e.g. speed deviations) or the motor to overheat and eventually be damaged.\u003C/p\u003E\n\u003Cp\u003EMotor circuit breakers are designed to trip when sensing a phase fault. This will occur after a couple of seconds when the motor is running at regular speed, or after only a few tenths of seconds when it\u2019s starting up.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E5.\u00A0\u00A0\u00A0 Risk of contactor damage and fire due to short-circuit\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe international standard for safety of machinery, EN 60204-1, requires at least Type 1 coordination between a circuit breaker and a contactor, in the case of a short circuit. Distribution circuit breakers are usually not tested in coordination with contactors; therefore, there\u2019s no performance guarantee of the combination. This means that if a short circuit occurs, the contactor can be destroyed and, worse, the amount of energy dissipated by the contactor during the interruption process can burn surround materials or ignite a fire.\u003C/p\u003E\n\u003Cp\u003EWith motor circuit breakers, short-circuit coordination can easily be selected: Type 1 ensuring no damage around the contactor, or Type 2 ensuring the contactor can still operate after the short-circuit event.\u003C/p\u003E\n\u003Cp\u003ESo you can clearly see, choosing a motor circuit breaker is critical to properly protecting motors and the installation. If you\u2019re an OEM, you may not always know in what kind of environment your machines will be installed. To maintain your customer\u2019s perception of quality, you need to ensure that your motors and machines are operating reliably under all conditions. During warranty periods and beyond, you need to make sure motors are protected while delivering the performance you promised. Having the right type of circuit breaker can be the difference between normal motor maintenance or costly substitution, and between continuous operation or costly disruption to your customer\u2019s productivity, or even a catastrophic fire.\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1.\u003Cstrong\u003E \u003Ca href=\u0022https://www.youtube.com/watch?v=eZ5WrvdBnGE\u0026amp;list=PL0AHvVniUcgwcgSxZ8bJbYGbHrqklEBLp\u0026amp;index=11\u0022\u003EWATCH\u003C/a\u003E \u003C/strong\u003ESchneider\u2019s motor management solutions\u003C/p\u003E\n\u003Cp\u003E2. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/contactus.html\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to us for a Schneider Electric solution for your facility\u003C/p\u003E\n\u003Cp\u003E3. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to receive these informative articles straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESource:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/power-management-metering-monitoring-power-quality/2019/03/28/5-ways-that-motor-circuit-breakers-provide-optimal-protection-for-motors/\u0022\u003Ehttps://blog.se.com/power-management-metering-monitoring-power-quality/2019/03/28/5-ways-that-motor-circuit-breakers-provide-optimal-protection-for-motors/\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n", "created": "Jan 2022", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Motor Protection pt 3 \u2013 Considering MPCBs", "nid": "602", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E\u003Cimg alt=\u0022Motor Protection pt 3\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00221afeb783-7bb3-4895-8a76-9194b9587f0b\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Motors%20-%20newsletter%20image%203_1.jpg\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EIn \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-Pt-1--The-importance-of-Motor-Protection\u0022\u003EPart 1\u003C/a\u003E \u003C/strong\u003Eof our series on Motor Protection, we outlined the importance of motor protection.\u003C/p\u003E\n\u003Cp\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-2--Circuit-Breakers-vs-Fuses\u0022\u003E\u003Cstrong\u003EPart 2\u003C/strong\u003E\u003C/a\u003E, we unpacked the major differences between fuses and circuit breakers, and posed a compelling argument as to why the latter should be preferred.\u003C/p\u003E\n\u003Cp\u003EWe\u2019re continuing the series with this third instalment by taking a look at four important reasons why you should specifically choose Motor Protection Circuit Breakers (MPCBs) for motor protection.\u003C/p\u003E\n\u003Cp\u003ESince the late 19\u003Csup\u003Eth\u003C/sup\u003E\u00A0century when they were invented, motors have transformed our lives. \u003Cstrong\u003EWhile most of us now take motors for granted, machine builders and industrial engineers must treat them very seriously because of the costs of downtime if any of them break down.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EA very common question is, \u201CWhy do we need a special motor protection circuit breaker (or MPCB)? Isn\u2019t a normal circuit breaker enough?\u201D\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-pt-2--Circuit-Breakers-vs-Fuses\u0022\u003E\u003Cstrong\u003EPart 2\u003C/strong\u003E\u003C/a\u003E, we discussed the catastrophic results of not adequately protecting your motors. In this post, we compare devices that are used for motor protection. Since approximately 80% of motors worldwide are rated at less than 15kW, we focus on the devices used to protect these motors, specifically contrasting miniature circuit breakers (MCBs) with thermal-magnetic MPCBs.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EBut first, let\u2019s clear up one common misconception \u2013 not all MCBs are created equal!\u003C/strong\u003E Depending on the type of load, the protection under short circuits (magnetic protection), and protection under overloads (thermal protection), there are different types of trip curves for MCBs. This article will talk only about two kinds:\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EC-curve MCB: Designed to protect general electrical distribution circuits from short circuits and overloads.\u003C/li\u003E\n\u003Cli\u003ED-curve MCB: Designed specifically to protect inductive circuits, including motors.\u003Ca href=\u0022https://www.magnet.co.za/contactus.html\u0022\u003E\u003Cimg alt=\u0022Fig 2\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002289044c44-7d7a-44e6-b8c7-bb3531fa29b4\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Schenider%20image%20for%20article_0.jpg\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003ENow, let\u2019s look at four important reasons that you should choose MPCBs for motor protection.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1.\u00A0\u00A0 Standards matter when it comes to circuit breakers\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EWhen comparing standards related to MCB and MPCB, it\u2019s clear there are some important differences:\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EMPCBs are certified under\u00A0IEC 60947-4, which is the relevant standard for motor protection. However, since they are fundamentally circuit breakers, they are also certified under IEC 60947-2.\u003C/li\u003E\n\u003Cli\u003EMCBs are typically certified under\u00A0IEC 60898-1\u00A0(residential applications), though many are also certified under\u00A0IEC60947-2. This is an important point: IEC 60898 is\u00A0\u003Cem\u003Enot\u00A0\u003C/em\u003Eintended for industrial environments. For example, it defines ambient temperature as 30 \u2070C, which is far too low for a typical factory setting. Even if you did choose an MCB which is certified under the correct standard, MCBs have no compensation for ambient air temperatures \u2013 a feature that is standard with Schneider MPCBs. This can cause nuisance tripping, with all the associated costs of downtime.\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp\u003E\u003Cstrong\u003E2.\u00A0\u00A0 Optimal short circuit performance\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ENow let\u2019s look at the performance of the devices under a short-circuit. First, a C-curve MCB is designed to trip between 5-10 times the rated current, whereas MPCBs are designed to trip at 12 times the rated current. The first reaction of many people to this is that the C-curve MCB is more sensitive and therefore superior but let me explain why that\u2019s not accurate.\u003C/p\u003E\n\u003Cp\u003EYou\u2019re dealing with an induction motor for which you\u00A0\u003Cem\u003Eexpect\u003C/em\u003E\u00A0to see an initial surge of current 8-10 times the rated current, by design. That\u2019s why the MPCB, which is specifically designed for this application, is designed to trip at higher currents \u2013 to avoid nuisance tripping. With the advent of high-efficiency IE3 and IE4 motors in the market, this problem is exacerbated as these motors have higher starting currents.\u003C/p\u003E\n\u003Cp\u003ESome try to get around this by selecting the MCB based not on the rated current, but on the trip current, i.e. they oversize the MCB to compensate. This can work to protect the motor from short-circuits but introduces issues under overload conditions, which I will discuss later.\u003C/p\u003E\n\u003Cp\u003EA D-Curve MCB, on the other hand, will work for short-circuit protection. However, you can\u2019t get a\u00A0\u003Ca href=\u0022https://blog.se.com/machine-and-process-management/2018/11/15/coordinated-motor-starters-the-right-choice-for-reduced-downtime-and-increased-safety/\u0022\u003Ecoordinated motor starter\u003C/a\u003E\u00A0with any MCB, so it\u2019s not a perfectly safe solution.\u003C/p\u003E\n\u003Cp\u003ESecond, the short-circuit breaking capacity of MCBs is generally restricted to 10 kA, which is often too low for industrial environments. Compare this with MPCBs that can offer up to 100 kA breaking capacity, which ensures that the motor starter and the motor remain safe and operable even in demanding conditions.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3.\u00A0\u00A0 Overload performance\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe most common faults that we see in motors are overload faults, accounting for over half the total motor failures worldwide. It\u2019s here that the MPCB really shines over the MCB. The table below shows the tripping behavior of an MPCB under overload conditions, as defined by trip classes in IEC60947-4\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/contactus.html\u0022\u003E\u003Cimg alt=\u0022Table 1\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022b628253f-d2ba-46a8-9bcd-88ad63adb9d5\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Table%201_2.png\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003ENow let\u2019s look at a similar table for MCBs.\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E\u003Cimg alt=\u0022Table 2\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u002201130f2e-686b-4a3e-9be8-7e1414c2d792\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Table%202.png\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EAs you can see, there\u2019s a clear difference. Repeated overloads of 50% or more can seriously damage the motor. The MCBs are clearly not going to trip fast enough to protect the motor windings. In addition, if you look at the last column, the issue becomes even more apparent. The C-curve MCB treats this as a short circuit and the D-curve trips within one minute, whereas the MPCB is much more sensitive and trips within 10s. Coming back to my earlier point, if you oversize the C-curve MCB to compensate for its lower tripping current, you end up running a huge risk of not protecting the motor at all under overloads.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E4.\u00A0\u00A0 Sensitivity to phase failure\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThere\u2019s one more problem with using an MCB for motor protection \u2013 it\u2019s not sensitive to phase failures. A phase failure in a motor is a serious issue that causes a surge in current in the other phases, again leading to overheating and damage to the winding. The MPCB will detect this as being equivalent to an overload in the other phases and trip as per the table above \u2013 the MCB will not.\u003C/p\u003E\n\u003Cp\u003EIn conclusion, an MCB is not adequate to protect your motor and using just an MCB is fraught with risk. Apart from this, an MPCB is easier to select as the motor ratings are clearly declared on the product itself. It is possible to tune it to your particular application with an accurately adjustable reference current. The operating life of an MPCB is also typically much higher than an MCB.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/download/magnet-te-sys-ebrochure.pdf\u0022\u003EDOWNLOAD\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s TeSys GV Range brochure \u00A0\u003C/p\u003E\n\u003Cp\u003E2. \u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/ww/en/work/products/product-launch/tesys/\u0022\u003EDISCOVER\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s solutions for protecting your entire machine application, not just the motor\u003C/p\u003E\n\u003Cp\u003E3. \u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/ww/en/work/products/industrial-automation-control/tools/motor-control-configurator.jsp\u0022\u003EEXPLORE\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s EcoStruxure\u2122 Motor Control Configurator\u003C/p\u003E\n\u003Cp\u003E4. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/contactus.html\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to us for a Schneider Electric motor protection solution for your assets\u003C/p\u003E\n\u003Cp\u003E5. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to receive these informative articles straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESource:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/power-management-metering-monitoring-power-quality/2020/04/27/dont-risk-motor-damage-4-reasons-to-choose-the-right-protection/\u0022\u003Ehttps://blog.se.com/power-management-metering-monitoring-power-quality/2020/04/27/dont-risk-motor-damage-4-reasons-to-choose-the-right-protection/\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n", "created": "Jan 2022", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Motor Protection pt 2 \u2013 Circuit Breakers vs Fuses", "nid": "601", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/contactus.html\u0022\u003E\u003Cimg alt=\u0022Motor Protection pt 2 \u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u0022d9c1931f-8aa1-46b6-9365-4cba1fd9eb2e\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Newsletter%20Motor%20Protection%20pt%202.JPG\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EIn this NEW series, we unpack motor protection. \u00A0\u003C/p\u003E\n\u003Cp\u003EIn \u003Ca href=\u0022https://www.magnet.co.za/solutions-electrical/news.php?type=articles\u0026amp;name=LEARN--Motor-Protection-Pt-1--The-importance-of-Motor-Protection\u0022\u003E\u003Cstrong\u003EPart 1\u003C/strong\u003E\u003C/a\u003E, we discussed the importance of motor protection.\u003C/p\u003E\n\u003Cp\u003EWe continue the series with Part 2 \u2013 a comparison of circuit breakers to fuses.\u003C/p\u003E\n\u003Cp\u003EIn the beginning, only fuses were used in electrical distribution systems to protect people and equipment against short circuits, circuit overloads, and other types of faults. Then, circuit breakers were introduced, offering many advantages over fuses.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ECircuit Breakers or Fuses?\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EFor processing and manufacturing operations, protecting motors is crucial to maintain productivity. As the cost of a fuse is typically much lower than a circuit breaker, fuses have often been the choice for this application. However, circuit breakers have evolved a lot in recent years.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EComparing modern circuit breakers to fuses reveals how circuit breakers can help machine manufacturers and facility management teams achieve greater safety and reliability, lower costs, and support for energy management initiatives.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1. Consistent performance\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EOne downside of fuses is that their performance can degrade due to aging, even causing them to open during normal conditions. In addition, there is no way to test a fuse, so you will never know the exact current value that will cause it to open. In contrast, circuit breakers are tested during manufacture and can also be retested during their operating life to ensure performance is maintained.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E2. Extended protection\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe breaking capacity of a circuit breaker can be greater than equivalent fuses (up to 150 kA). And under overload conditions, a circuit breaker can trip up to 1000 times faster than a fuse. Some circuit breakers also provide exceptional fault current limitation, a capability previously associated only with fuses. This not only supports reliable protection, it also reduces asset aging and extends service life. Another aspect of protection to keep in mind is that it\u2019s common for only one of three fuses to open, causing a motor to continue running on two phases, as well as potentially experiencing an overload. This will never happen with a circuit breaker, which will always break all three phases simultaneously.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3. Enhanced safety and uptime\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe use of fuses can represent a safety risk for technical personnel. Due to exposed conductors, replacement of fuses can be dangerous for unskilled people. The connections to circuit breakers are hidden behind the device, and operation can be done remotely. This makes breakers safer, especially for unskilled workers. One of the reported causes of fires in industrial environments is a fuse that has been replaced with the wrong model or rating, or even with wires or paper clips. These kinds of mistakes are avoided with circuit breakers, as they usually do not require replacement after a trip. Additionally, replacing fuses takes more time than simply reclosing a breaker. This means circuit breakers help minimize downtime and production losses.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E4. Cost savings\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EAs mentioned above, the cost of a single fuse is significantly less than the cost of a circuit breaker. However, when we consider the complete cost of an installation, there are other costs that need to be taken into account. First, of course, is that three fuses are required for a three-phase circuit, with each fuse requiring the cost of a fuse base. Second, unlike circuit breakers, fuses do not have any built-in switching capability, so the addition of an upstream switch is required. Fuses also require a larger enclosure, due to their heat dissipation. And finally, when one of three fuses opens, all three fuses should be replaced. This requires an expensive replacement stock of fuses to be kept on hand. So, in total, the complete cost of using fuses can be greater than a circuit breaker. Though occasional replacement of circuit breakers may be necessary, a single model of breaker can usually be used for different power ratings, which minimizes inventory.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E5. Greater functionality\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EUnlike fuses, circuit breakers can be enhanced with additional functions, such as ground fault protection. They also allow for system coordination between breakers (e.g. selectivity, cascading). The newest, most advanced circuit breakers offer a large breadth of capabilities in a compact size with flexible designs that enable field-upgrading. Add-ons can include remote control and status indication, alarm and auxiliary contacts, power and energy measurements, and network communications.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EIn summary\u003C/strong\u003E\u003C/p\u003E\n\u003Ctable align=\u0022left\u0022 border=\u00221\u0022 cellpadding=\u00220\u0022 cellspacing=\u00220\u0022\u003E\n\u003Ctbody\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003E\u003Cstrong\u003ECircuit Breakers\u003C/strong\u003E\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003E\u003Cstrong\u003EFuses\u003C/strong\u003E\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ETested during manufacture\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ENo way to test a fuse\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ECan be enhanced with additional functions\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ECannot be enhanced\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003EAlways breaks all three phases simultaneously\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ECommon for only one of three fuses to open\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ESafer, usually do not require replacement after a trip\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003EReplacement of fuses can be dangerous and time consuming\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ECosts more, but replacement is only required occasionally\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ECosts less, but the complete cost of using fuses can be greater than a circuit breaker\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003Ctr\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003EBuilt-in switching capability\u003C/p\u003E\n\u003C/td\u003E\n\u003Ctd style=\u0022width:301px;\u0022\u003E\n\u003Cp\u003ENo built-in switching capability\u003C/p\u003E\n\u003C/td\u003E\n\u003C/tr\u003E\n\u003C/tbody\u003E\n\u003C/table\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/download/magnet-schneider-te-sys.pdf\u0022\u003EDOWNLOAD\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s TeSys GV4 thermal-magnetic and magnetic motor protection circuit breakers data sheet\u003C/p\u003E\n\u003Cp\u003E2. \u003Cstrong\u003E\u003Ca href=\u0022https://www.youtube.com/watch?v=8KEGajX4qs4\u0026amp;list=PL0AHvVniUcgwcgSxZ8bJbYGbHrqklEBLp\u0026amp;index=18\u0022\u003EWATCH\u003C/a\u003E\u003C/strong\u003E TeSys Island Digital Load Management System\u003C/p\u003E\n\u003Cp\u003E3. \u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/ww/en/work/products/product-launch/tesys/\u0022\u003EDISCOVER\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s solutions for protecting your entire machine application, not just the motor\u003C/p\u003E\n\u003Cp\u003E3. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/contactus.html\u0022\u003ECHAT\u003C/a\u003E\u003C/strong\u003E to us for a Schneider Electric motor protection solution for your assets\u003C/p\u003E\n\u003Cp\u003E5. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E to receive these informative articles straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESource:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/machine-and-process-management/2018/06/19/motor-protection-5-reasons-to-choose-circuit-breakers-over-fuses/\u0022\u003Ehttps://blog.se.com/machine-and-process-management/2018/06/19/motor-protection-5-reasons-to-choose-circuit-breakers-over-fuses/\u003C/a\u003E\u003C/p\u003E\n", "created": "Jan 2022", "terms": "Electrical, Education, Schneider" }, { "title": "LEARN | Motor Protection Pt 1 \u2013 The importance of Motor Protection", "nid": "585", "body": "\u003Cp\u003E\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E\u003Cimg alt=\u0022LEARN | Motor Protection Pt 1 \u2013 The importance of Motor Protection\u0022 data-entity-type=\u0022file\u0022 data-entity-uuid=\u00222c00ced6-8d45-4801-9fa9-69991251126c\u0022 height=\u0022205\u0022 src=\u0022/cms/drupal8-magnetgroup/sites/default/files/inline-images/Motor%20Protection_2.jpg\u0022 width=\u0022430\u0022 class=\u0022align-center\u0022 /\u003E\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003EDid you know that improperly protected motors might result in unexpected production downtime, losses, and breakdowns in the machinery? In this NEW series, we unpack the many facets of motor protection. We kick off Part 1 with an overview as to the importance of adequately protecting motors.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EWhy protect your motors? \u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0\u00A0 \u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe basic idea behind electric motors is pretty simple \u2013 supply electricity at one end and a metal rod or an axle at the other end, which will provide you with power to drive a machine. This traditional form of generating electricity has now been in existence for more than 200 years and is now an advanced technical breakthrough in the field of power generation and industrial automation.\u003C/p\u003E\n\u003Cp\u003EThe manufacturing industry in today\u2019s market dominates the industrial sphere. In this sector, a major portion of power is consumed to convert raw materials into finished goods. It is a mandatory resource, as over 50% of the work in today\u2019s manufacturing plant is attained by electric motors or new-age\u00A0servo motors. As per a research study to understand the electricity consumption trends, this percentage will continue to increase to sustain the production rate in the future.\u003C/p\u003E\n\u003Cp\u003EThus, it\u2019s not really all that surprising that the production and manufacturing sector is dependent on electric motors. It\u2019s essential to ensure that motors and\u003Cstrong\u003E\u00A0\u003Ca href=\u0022https://www.se.com/in/en/product-category/3000-motor-starters-and-protection-components/\u0022\u003Emotor starters\u003C/a\u003E\u003C/strong\u003E\u00A0are adequately protected. If you follow this, then it will provide you with maximum operating time and cut down on any chance of outages.\u003C/p\u003E\n\u003Cp\u003EAnother thing to keep in mind is that, over the last few decades, a major amount of resources have been deployed to make the operating systems even more efficient. The control manufacturers are mainly involved in the development of improved and cost-effective\u00A0\u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/in/en/product-subcategory/4665-motor-protection/\u0022\u003Emotor protection\u003C/a\u003E\u003C/strong\u003E\u00A0devices.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EThe role of relays\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003ETo ensure motor protection, overload relays are used in circuits to protect motors and motor conductors. This saves the system from any damage caused by prolonged periods of overcurrent circuit conditions. \u003Cstrong\u003ESome of the functions of these relays are:\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EIt allows harmless, temporary overloads (like in the case of motor starters) without disrupting the circuit.\u003C/li\u003E\n\u003Cli\u003EThey trip and open a circuit if the current is high enough to cause motor damage over a while.\u003C/li\u003E\n\u003Cli\u003EIt can reset once the overload is removed. If the motors are exposed to the increased levels of continuous current and prolonged periods at locked rotor condition, severe damage to the motor and motor circuit conductors might occur.\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp style=\u0022margin-left:36.0pt;\u0022\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EThe motors can be damaged or destroyed under any of the following conditions:\u003C/strong\u003E\u003C/p\u003E\n\u003Cul\u003E\n\u003Cli\u003EHigh or low supply voltage\u003C/li\u003E\n\u003Cli\u003EPhase unbalance\u003C/li\u003E\n\u003Cli\u003EContinuous excessive loading\u003C/li\u003E\n\u003Cli\u003ESingle-phasing\u003C/li\u003E\n\u003Cli\u003EJam or stall conditions\u003C/li\u003E\n\u003Cli\u003EGround/earth faults\u003C/li\u003E\n\u003Cli\u003EMechanical failures like seized motor bearing or binding mechanical linkages\u003C/li\u003E\n\u003C/ul\u003E\n\u003Cp style=\u0022margin-left:36.0pt;\u0022\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003EIn the end, the integration of proper servo motors can turn out to be quite beneficial, as it will ensure that the system of power management is optimised to the fullest. This will ensure that little to no problems are faced by businesses further down the line, ultimately leading to a situation where the goal of proper\u00A0\u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/in/en/product-subcategory/5430-power-management-system/\u0022\u003Epower management\u003C/a\u003E\u003C/strong\u003E\u00A0can be accomplished very quickly.\u003C/p\u003E\n\u003Cp\u003EWhen talking about\u00A0\u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/in/en/product-subcategory/4665-motor-protection/\u0022\u003Emotor protection\u003C/a\u003E\u003C/strong\u003E\u00A0, if they are not adequately sized or configured, two possible scenarios can unfold. There are a few cases where they trip continuously and will consume valuable time from your maintenance staff, and in some cases they may not even trip in response to slight under voltage or overload, conditions that are not always evident and which reduce the service life of motors.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ETo avoid some of the common mistakes while configuring motor protections, the following are the steps one should bear in mind.\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E1)\u00A0Under voltage Protections Set Too High\u00A0\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EMotors that are operating below their rated voltage might suffer from overheating and have a shorter life cycle. The National Electrical Manufacturers Association (NEMA), they do not recommend operating motors below 90% of their rated voltage for extended periods. Make sure that if an under voltage protection is set too high, it can, and probably will, disconnect the motor when not required.\u003C/p\u003E\n\u003Cp\u003EFor instance, three-phase motor if it has a rated voltage of 230V, which means the lowest operating voltage acceptable according to NEMA is 207V (230V x 90%). However, if an adjustable under voltage relay is set at 220V, a 5% reduction in voltage will be enough to disconnect the motor.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E2)\u003C/strong\u003E\u00A0\u003Cstrong\u003EThermal Overload Set Incorrectly\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EThe basic requirement for overload protection setting for motors is 125% of their full-load current according to the NEC; however, it makes sure you read the overload relay instructions.\u003C/p\u003E\n\u003Cp\u003ESome manufacturers have the 125% setting built in, which means you must set the overload protection at the motor\u2019s nameplate current.\u003C/p\u003E\n\u003Cp\u003EIf the 125% value is not built into the relay, you must set it at the motor\u2019s nameplate current \u002B 25%.\u003C/p\u003E\n\u003Cp\u003EFor example, assume you want to protect a motor with 60A of full-load current, and you have an overload relay that can be set from 50A to 100A. If the device already factors in the 125%, you must set it at 60A. If not, the correct setting is 75A (60A \u002B 25%).\u003C/p\u003E\n\u003Cp\u003EIf overload protection is set too low, the motor can be disconnected even when operating normally. For example, if the protection device described above came with the dial set at 50A, and it was left that way for a 60A motor, it may not trip immediately if the engine is just lightly loaded which gives the impression that it is working correctly. However, higher motor loads that bring current above 50A will trip the device.\u003C/p\u003E\n\u003Cp\u003EOf course, overload protection shouldn\u2019t be set too high either, since the motor will not be protected adequately from overload. For example, if you add 25% when setting an overload relay that already has the 125% value built in, the actual overload protection value will be 156%, which does not meet the NEC.\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003E3)\u003C/strong\u003E\u00A0\u003Cstrong\u003EMagnetic Protection Set Incorrectly\u00A0\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003EIn the circumstances like fault conditions, magnetic protections must disconnect the motor immediately but must allow the inrush current without disconnection. Another thing that one should keep in mind is that if the magnetic protection is fixed, make sure its trip curve allows the inrush current, which can be up to 800% of rated current only. Whereas, if the magnetic protection is adjustable, then set a value so that it will not trip with the inrush current. Make sure that the inrush current is lower, if the motor has a reduced-voltage starter, a solid-state starter or a variable frequency drive.\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003EResources:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E1. \u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news.php?type=articles\u0026amp;name=PRODUCT-NEWS--Easy-Overcurrent-Protection-with-Schneiders-Easergy-P3\u0022\u003EDISCOVER\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s Easergy P3 Relay for MV Applications\u003C/p\u003E\n\u003Cp\u003E2.\u003Cstrong\u003E\u003Ca href=\u0022https://www.se.com/in/en/product-subcategory/2935-servo-drives-and-servo-motors/\u0022\u003E EXPLORE\u003C/a\u003E\u003C/strong\u003E Schneider\u2019s Servo Drives and Motors\u003C/p\u003E\n\u003Cp\u003E3. \u003Ca href=\u0022https://www.magnet.co.za/contactus.html\u0022\u003E\u003Cstrong\u003ECHAT\u003C/strong\u003E\u003C/a\u003E to us for a Schneider Electric solution for your facility\u003C/p\u003E\n\u003Cp\u003E4.\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E \u003C/a\u003E\u003Cstrong\u003E\u003Ca href=\u0022https://www.magnetgroup.co.za/news-letter.html\u0022\u003ESUBSCRIBE\u003C/a\u003E\u003C/strong\u003E\u003Ca href=\u0022https://www.magnet.co.za/news-letter.html\u0022\u003E \u003C/a\u003Eto receive these informative articles straight to your inbox\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u00A0\u003C/p\u003E\n\u003Cp\u003E\u003Cstrong\u003ESource:\u003C/strong\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/industrial-software/2019/05/22/importance-of-motor-protection-in-modern-industries/\u0022\u003Ehttps://blog.se.com/industrial-software/2019/05/22/importance-of-motor-protection-in-modern-industries/\u003C/a\u003E\u003C/p\u003E\n\u003Cp\u003E\u003Ca href=\u0022https://blog.se.com/industrial-software/2019/03/07/motor-protection-three-common-mistakes-and-how-to-avoid-them/\u0022\u003Ehttps://blog.se.com/industrial-software/2019/03/07/motor-protection-three-common-mistakes-and-how-to-avoid-them/\u003C/a\u003E\u003C/p\u003E\n", "created": "Dec 2021", "terms": "Electrical, Education, Schneider" } ]