Question 1

How do I connect / wire a contactor and overload to create a Direct On Line (DOL) Starter?

Accepted Answer

Attached is a .pdf file with pictorial diagrams (1) of how you would connect the four most common variants of a DOL starter.They show diagrams for 240 and 415 VAC control. The most common for small Direct On-Line Starters (DOLs) is 415VAC, as this requires no neutral to be fed to the starter.Options are also given for using either a remote stop switch or for using the stop button which is integral with the overload. In the latter case the stop button is not a switch, it is a plunger type device fitted into the lid/door of the enclosure, which will physically press the overload stop. This is the method that is used in the Schneider Electric TeSys enclosed motor starters, such as the TeSys LE range.Remote and Emergency stops(2) are shown fitted between terminals A2 and 96, though they can also be fitted between 14 and 95, or even both if multiple stops are involved.WarningParticular care must be taken to accurately fit the stop button when using the plunger type stop without any additional remote stop, as if for any reason the plunger does not activate the stop button on the overload, there will be no way of stopping the motor without disconnecting the supply.NOTES:(1) These drawings are functional schematics. It remains the responsibility of the installer to ensure that the requirements of local directives and legislation are met and that appropriate circuit protection is provided.(2) Inclusion of E stops in these circuits is purely for illustrative purposes and may be acceptable in simple relatively low risk safety systems. However, depending on the risk assessment carried out on the plant it may not be appropriate, other Emergency Stop facilities may be necessary, particularly in high risk applications. Consult you safety consultant.NOTE regarding Terminal NumberingThe circuits are based upon TeSys D range contactors and overloads. Terminal numbering is to a common standard so most other contactors can be wired similarly. However, be aware that there are contactors that use different numbering systems.NOTE if using TeSys KThe TeSys LR2K overloads (LR2K****) for use with TeSys K range contactors (LC1K****) have additional pins on their overloads to make direct connection to terminals 14 on contactor to 95 on overload and A2 on contactor to 96 on overload. The diagrams provided in the attached PDF file do not relate to such TeSys K systems unless the 2 right hand pins are first removed. These pins are specially weakened for this purpose and may easily be snapped off by bending backwards with a pair of pliers as shown for one pin on the diagram belowHowever, doing this is just making extra work. It is better to wire in accordance with the K Series diagram.

Question 2

Altivar drive is showing dCb on the display.

Accepted Answer

Issue: What is the error code dCb on the Altivar Drive's display. Product line: Altivar drive families: ATV12, ATV28, ATV312, ATV32, ATV61, ATV71. Environment: All models, all serial numbers. Cause: DC Injection Braking. Resolution: This is a normal drive state. It is indicating the drive is injecting DC current into the motor to slow the motor down. This typically appears on deceleration or at the end of the deceleration ramp. On some drives, DC Injection can be turned on using a Logic Input.

Question 3

What is the definition of zero-sequence impedance for a three-phase winding transformer?

Accepted Answer

The zero-sequence impedance is between connected together line terminals of a three-phase star-connected or zigzag-connected transformer windings and its neutral terminal. Zero-sequence impedance expressed in ohms per phase at rated frequency. NOTE 1. The zero-sequence impedance may have several values because it depends on how the terminals of the other winding or windings are connected and loaded.NOTE 2. The zero-sequence impedance may be dependent on the value of the current and the temperature, particularly in transformers without any delta-connected winding. NOTE 3. The zero-sequence impedance may also be expressed as a relative value in the same way as the short-circuit impedance.

Question 4

UPDATED MARCH-2016: Unable to access my APC Network Management Card (NMC) enabled device via HTTPS (SSL/TLS)

Accepted Answer

IssueThe user is unable to access their APC Network Management Card (NMC) products via HTTPS (SSL/TLS) secured web access.There are two parts to this issue, both of which occur when the user has their Network Management Card product configured for SSL (HTTPS). Companies such as Microsoft, Mozilla, and Google are disabling SSLv3.0 in their browser products due to numerous security vulnerabilities that exist. One such vulnerability is POODLE (https://www.openssl.org/~bodo/ssl-poodle.pdf). TLSv1.0, at a minimum, is the advised protocol. TLS does not work on the current NMC products. Therefore, the NMC will fall back to SSLv3.0 and as such, be vulnerable to POODLE. Examples: An example of this problem, shown via Firefox, is below. A NetBotz Rack Monitor 200 (SKU# NBRK0201) is configured for HTTPS. The user has Firefox v34.0 installed. The user opens their web browser and types the IP address into address bar. The user is presented with the following error message: Another example of this problem, via Internet Explorer, is below. A NetBotz Rack Monitor 200 (SKU# NBRK0201) is configured for HTTPS. The user has Internet Explorer v11.0 installed. The user opens their web browser and types the IP address into address bar. The user is presented with the following error message: Another example of this problem, via Chrome, is below. An AP9631 Network Management Card is configured for HTTPS. The user has Chrome v39 installed. The user opens their web browser and types the IP address into the address bar. The user is presented with the following error message: Browser error messages may include: ERR_SSL_FALLBACK_BEYOND_MINIMUM_VERSION, ssl_error_no_cypher_overlapNote: If you've received mozilla_pkix_error_inadequate_key_size, sec_error_invalid_key, or anything referring to invalid key size/length, please consider reviewing knowledge base article ID FA162031 as this may be due to a separate issue entirely or an additional issue.Product Line Network Management Card 1 (NMC1) - AP9617, AP9618, AP9619 Devices with an embedded Network Management Card 1 include (but are not limited to): Metered/Switched Rack PDUs (AP78XX, AP79XX), Rack Automatic Transfer Switches (AP77XX), Environmental Monitoring Units (AP9320, AP9340, NBRK0201), AP9921X Battery Management System, ACFXXX Rack Air Removal Unit, PDPMXXX Modular Power Distribution, AP9361 Rack Access PX-HID, and ACRCXXX, ACRPXXX, ACRDXXX, ACSCXXX, RACSCXXX Cooling Units (except ACDA901, ACRC301H, ACRC301S). Network Management Card 2 (NMC2) - AP9630/30CH, AP9631/31CH, AP9635/35CH Devices with an embedded Network Management Card 2 include (but are not limited to): 2G Metered/Switched Rack PDUs (AP84XX, AP86XX, AP88XX, AP89XX), G50 AV Units, Smart-UPS Online (SRT), and ACDA901, ACRC301H, ACRC301S Cooling Units, EnvironmentAny customer who uses any one of the products mentioned previously and: Configures their product for SSL (HTTPS).Uses a web browser version that does not allow for web access via SSLv3.0. Note: HTTP users are not affected. Meaning, if you have not enabled HTTPS (SSL), web browsing will work normally.CauseCompanies such as Microsoft, Mozilla, and Google are disabling SSLv3.0 in their browser products due to numerous security vulnerabilities that exist. One such example is POODLE (https://www.openssl.org/~bodo/ssl-poodle.pdf). TLSv1.0, at a minimum, is the advised protocol.Current NMC products have an inability to properly utilize TLS extensions recently released in several modern browsers. With this inability, the NMC device is unable to connect to the browser via TLS. While future versions of the NMC1 devices will not update the underlying cryptology engine, NMC2 devices will be updated to work with current TLS specification and and operate properly with modern browsers.ResolutionA customer can avoid this problem either by utilizing other access methods on the Network Management Card or they can modify their web browser to allow SSLv3.0 usage (at their own discretion). Other access methods for the Network Management Card are as follows: Local consoleWeb (HTTP)Telnet/SSHSNMPv1/v3 Modifying a web browser to allow SSLv3.0 usage should be addressed by the user’s network security team or facility manager. Schneider Electric will not provide users with instructions on modifying web browser settings. Some users may be prohibited from enabling SSLv3.0 through their web browser.Any of the following NMC1 products do not currently have any firm future firmware update plans to address this or any future vulnerabilities: AP9921X Battery Management SystemAP7750, AP7722, AP7701 Rack Automatic Transfer SwitchesAP9340, AP9320 Environmental Monitoring UnitsS20BLK A/V Power Conditioner & Battery BackupPDPMXXX Modular Power DistributionFM35XX Network Air, ACDA901, Stulz C7000 Details regarding firmware availability for Network Management Card 1 (NMC1) based products, providing TLS 1.0, are shown in the table below: NMC1 (AP9617/18/19/mini-NMC1) Application NameProduct(s) Firmware Application is used withAOS Version with TLS FixAvailable Now?px2Symmetra PX 48/96/100/160 kVA embedded UPS brainAOS v3.9.0 and higherYesrpduAP7XXX series Rack PDU (ex. AP7941)AOS v3.9.0 and higherYesacrcACRCXXXX InRow Chilled Water (except ACRC3XXX)AOS v3.9.0 and higherYes (via your local APC Cooling Support team)g2atsAP7XXX Rack Automatic Transfer Switch models except AP7701, AP7722, AP7750AOS v3.9.0 and higherYesacrpACRC5XX, ACRP1XX, ACRP5XX, ACRD5XX InRow RC, RP, RDAOS v3.9.0 and higherYes (via your local APC Cooling Support team)acscACSC1XX InRow SCAOS v3.9.0 and higherYes (via your local APC Cooling Support team)raruACFXXX Rack Air Removal UnitAOS v3.9.0 and higherNoacrptkACRD1XX, ACRD2XX InRow RDAOS v3.9.0 and higherYes (via your local APC Cooling Support team)nb200NetBotz 200 Rack Monitor (NBRK0201)AOS v3.9.0 and higher.YespxhidAP9361 Rack Access PX-HIDAOS v3.9.0 and higherYes Note: Certain browsers may also require setting changes to allow TLS 1.0 or TLS 1.0 fallback too, such as Firefox v37+. Schneider Electric will not provide step by step instructions for modfying web browser settings for liability reasons but if you're comfortable modifying settings at your own risk, security.tls.version.fallback-limit within Firefox will likely need to be changed from a default value of 3 (forcing TLS 1.2) to a value of 1 to allow fallback to TLS 1.0. This setting also sometimes resets itself between Firefox browser upgrades. Newer Chrome versions may require --ssl-version-fallback-min=tls1 to be appended to the program shortcut.A fix to address this problem in the Network Management Card 2 (NMC2) and NMC2 enabled devices has been implemented. The release date will be determined on a product by product basis. See below for available updates for NMC2 firmware applications. These updates provide TLS 1.0, TLS 1.1 and TLS 1.2 functionality. NMC2 (AP9630/31/35/mini-NMC2) Application NameProduct(s) Firmware Application is used withAOS Version with TLS FixAvailable Now?sumx1ph/3ph Smart-UPS, MGE Galaxy 3500, MatrixAOS v6.4 and higherYessy1ph Symmetra Power Array, Symmetra RM, Symmetra LXAOS v6.4 and higherYesrpdu2gAP8XXX series Rack PDU 2G (ex. AP8941)AOS v6.4 higherYessypxSymmetra PX 250/500 kVA (w/AP9635 only)AOS v6.3.2 and higherYes (via your local 3-phase technical support team)sy3pSymmetra PX 20/40/80 kVA Note: See knowledge base ID FA245145 for more compatibility detailsAOS v6.3.2 and higherYesacrc2gACRC3XXXAOS v6.3.2 and higherNo, pending release tentatively for end of Q3 2015.unflrleHDCV45XXX, HDCV50XXX, T(D/U)(A/D/E/T/W)VXXX Uniflair LETBDNo, pending release tentatively for Q2 2016.g300Galaxy 300AOS 6.4 and higherYes Can this problem be confused with other error messages generated by the Network Management Card?Yes, a user may receive different error messages relating to SSL/TLS when configuring or accessing their Network Management Card device. It is imperative that Schneider Electric and the user identify the exact error message that the user is receiving and confirm that it relates to this specific issue, related to SSLv3.0.For example, similar symptoms could be experienced by the issue in knowledge base article ID FA162031 - Network Management Card 1 (NMC1) Information Bulletin: Effects of Microsoft Internet Explorer and other web browsers blocking key lengths less than 1024 bits​(blocking key lengths less than 1024 bits)Note: If there are any questions, problems, or concerns related to the content of this article, please contact your local technical support team for further assistance.

Question 5

Floating Neutral in UPS Battery Mode - Causes and Implications

Accepted Answer

When a single-phase UPS with double pole back-feed protection is operating in battery mode, a voltage between neutral and earth may be observed. This phenomenon is typically due to the absence of a neutral-to-earth bond during battery operation, this creates an IT Earthing Network, resulting in a floating neutral. This is normal as there is double pole isolation in these units. When the unit is online it is obviously having an earth from the supply. When it goes on battery or should the supply be disconnected, both poles will be disconnected from the supply thus creating something similar to an IT Earthing Network.. The supply has then no reference to the earth, so the first fault is not a safety hazard. Schneider Electric single phase UPS units comply to CE standards so this shouldn’t be an issue but if for some reason the customer requires a system with earth reference, then they can use a transformer, such as SURT002. The reason for double pole isolation, is that it is sold in countries where the plug can be easily reversed, e.g. the German Shuko Socket. For the 3 phase and larger UPS systems, the neutral is not broken so this type will always maintain a reference to earth is a TN-CS network. Here's a detailed explanation: Why Voltage Appears Between Neutral and Earth in Battery Mode Floating Neutral Condition In battery mode, the UPS inverter generates the output voltage. When the inverter output loses the neutral-to-earth bond, the neutral is floating, it has no defined reference to earth. This causes the neutral to drift electrically, and a voltage can appear between neutral and earth, often around half the line voltage. For a 230V system this can vary, usually it is a value between 50V and 115V depending on various factors, such as load, type of common-mode filters or EMI suppression components, capacitive coupling, cable layout, etc. This occurs for one or more of the following reasons: 1. Double Pole Back-feed Protection Double pole protection means both line and neutral are disconnected from the grid when the UPS switches to battery. This is required by standards like IEC 62040, to prevent back-feed into the grid and ensure safety. However, disconnecting the grid also removes the neutral-earth bond that was established at the main panel or transformer. 2. Capacitive Coupling and Common Mode Filters UPS systems often include EMI filters and capacitive components between line, neutral, and earth. These can create a capacitive voltage divider, causing measurable voltages between neutral and earth even when no current is flowing. 3. Separately Derived System A UPS without an internal isolation transformer can still be considered a separately derived system. In such cases, a neutral-earth bond must be switched in during battery mode to maintain reference. While this is common practice in the US the international units do not have such a bonding relay And this causes the neutral to float, leading to voltage readings. 4. Are there any safety issues? No, the IEC 62040 has established that there in no danger associated with this. In fact, it becomes an IT earthing network, and this is a network used in critical installations such as hospitals, due to its enhanced safety characteristics. 5. How to resolve or prevent this? In most cases this is not an issue but where it causes problems, an isolation transformer can be installed on the UPS output to create a separately derived system with a stable neutral-earth bond. In the US a bonding relay is used, this switches in a neutral-to-earth connection when the UPS enters battery mode. However, in Europe, many local regulations do not allow this configuration. Ensure compliance with local regulations which requires a new earthing arrangement in island mode. The above drawing shows the behaviour of a Line Interactive UPS. Online UPS units behave in a similar manner as far as the floating neutral is concerned. To sumarise, Schneider Electric single phase UPS units comply to CE standards so this shouldn’t be any concerns, safety or otherwise. There is a further FAQ: 000141153 which covers behaviour for 3 Phase units.

Question 6

Factory reset of M580 CPU with Engineering Link set to "Enforced"

Accepted Answer

Issue: Unable to connect to M580 because the password was forgotten and the Engineering Link mode was set to "Enforced". When Engineering Link is set to Enforced, you are forced to create an application password. Also the only protocols that can now be used to connect are: HTTPS HTTPS via USB when using those protocols, you can no longer use the SHIFT + F2 method to obtain a code that will allow engineering to provide a recovery password if you forget the application password. Also the method of moving the CPU one slot over to the right does not work in this mode. We are left with no method of clearing the CPU back to NO CONF mode. Products: M580 CPU with firmware 4.20 and up Control Expert 16.0 and up Resolution: There are 2 methods that can allow us to recover the CPU with an "Enforced" engineering link. Method 1 : This method will require you to know the password for the firmware update. Using EcoStruxure Automation Device Maintenance, you can downgrade the CPU back to firmware 4.10. Since this version did not support the Engineering link feature, the CPU will reject and erase the application when downgrading. Method 2 : This will require an M580 SD card (BMXRMS004GPF) and a spare M580 CPU of the same model In the spare CPU, create an application with no application password. The engineering link mode might have to be set to "Full Access". Make sure to insert the SD card in the CPU before transferring this application in the spare CPU. Once this is done, power down the spare CPU and retrieve the SD card. Power down the "locked" CPU and insert the SD card. Power the CPU back up. The program in the SD card will overwrite the one in the CPU, effectively replacing the application with the "Enforced" option.

Question 7

Cannot login to PME Web with error User is Not Licensed

Accepted Answer

IssueThe following error occurs when the user tries to login into PME Web: Access denied. This user is not licensed for web access. Product LinePower Monitoring Expert 9.xPower Monitoring Expert 2020Power Monitoring Expert 2021Power Monitoring Expert 2022Power Monitoring Expert 2023 Power Monitoring Expert 2024EnvironmentPME Web ApplicationCausePME web licenses are assigned to users as they log in. If a user is deleted after having a license assigned to it, the SQL database may take time to register the change. If the maximum number of web licenses had previously been reached this means new users that are created will not be able to be licensed as the number of users exceeds the number of available web licenses. Resolution *Warning: Irreparable database damage can occur. This procedure should only be performed by users familiar with SQL Server Management Studio. Databases should be backed up prior to performing this procedure.* The assigned license can be manually freed in the SQL database. In order to achieve this run the following script:delete FROM [ION_Network].[dbo].[GroupMembershipMap] where TrusteeID NOT IN (SELECT UserID FROM [ION_Network].[dbo].[Users])For convenience the script is attached to this article.

Question 8

Altivar - What are the possible causes for status code nSt appearing on the display ?

Accepted Answer

Product series:Altivar ATV variable speed drivesThe display status nSt means a freewheel stop of the drive.This is not an error code but drive status indication. lf the drive display shows nSt, it can not be started in “local” or “remote” control.Remedy:1:) In case of 3-wire control mode: check for the NC-contact ( stop ) on LI1 is opened.2:) In case of 2-wire control mode: check in 2-wire control type is set to “level control” ( LEL ) or check if the run command on LI1 is present during powering-up of the drive. 3:) nSt can be assigned to a logical input and this input is open ( 0V ).4:) The STOP button on the locale contol path of the drive or on the external control is being activated while the drive has an activated command on the terminals. 5:) The drive is in CIA402 (DSP402) “drive com NET command mode” and did not receive the right command for rdY or rUn. 6:) A control tension " dip" of the +24V power supply can also be the cause to get the drive into nSt (freewheel stop).

Question 9

What does light or dark switching mean when referring to photo electric sensors?

Accepted Answer

Please note - As of 01/09/23 the Telemecanique Sensors range is no longer part of Schneider Electric. This FAQ is now for reference only. For further information and contact details for Telemecanique Sensors, please visit their website; https://www.telemecaniquesensors.com/uk/en There are 3 main types of photo electric sensor used for detecting an object; Diffuse (sometimes also called proximity mode or direct detection). There is also a variation of diffuse called diffuse with background suppression (diffuse with BGS).Retro reflective (sometimes also called reflex). There is also a variation of reflex called polarised reflex (or polarised retro reflective). Through beam (sometimes also called thru' beam). Determining normally open (N/O) or normally closed (N/C) operation? Both the retro reflective and through beam sensors rely on the object 'breaking' the beam in order for it to be detected. Whereas the diffuse system requires the object itself to reflect the light beam.Because of this fundamental difference in the way the sensors detect an object, retro reflective and through beam sensor outputs are the inverse of diffuse sensors. This leads to a lot of confusion. Historically Within the photo electric industry, to overcome the confusion of referring to N/O or N/C outputs, the term 'light switching' and 'dark switching' was introduced; Light switching; A sensor that is light switching switches it's output 'on' when the light beam is returned to the receiver. i.e. If N/O operation is required, a light switching diffuse sensor could be used. Dark switching; A sensor that is dark switching switches it's output 'on' when the light beam blocked from returning the beam to the receiver. i.e. If N/O operation is required, a dark switching retro reflective or through beam sensor could be used. Recent developments To simplify product selection, Schneider Electric (under the Telemecanique brand) pioneered the concept (launched as Osiconcept) of 'object detection' with it's Osiris multimode range of sensors. With these products, irrespective of whether the sensor is configured for retro reflective, through beam or diffuse the output will default to N/O. Another feature of these multimode sensors is the ability to invert the output to achieve a N/C mode of operation.

Question 10

What is the difference between the REFLEX mode and the POLARISED REFLEX mode on photo-electric sensors?

Accepted Answer

Note that we no longer sell these devices, this FAQ is for information only. Both systems comprise a transmitter and receiver (usually within a single-body sensor), and a reflector. The transmitter sends a beam which is bounced back by the reflector and detected by the receiver. An object passing through the beam blocks the reflection and triggers the sensing signal.REFLEX mode sensors may not be suitable for detecting reflective objects, as a shiny target may bounce the beam back to the sensor in the same way as the reflector. The sensor may not be able to tell the difference between the target and reflector and will therefore fail to detect the object. For maximum effectiveness the targets should be opaque or near opaque and should not be highly reflective in nature. However, the advantage of reflex mode sensors is that they give relatively long sensing distances.POLARISED REFLEX mode sensors have polarising filters over both the transmitter and receiving sensor. The filters are at 90 deg to each other which means that the receiver cannot see the transmitted beam as it will be blocked by the receiver filter. The reflector turns the polarised light waves through 90 deg so that the receiver can see them. Light bouncing off other objects is not rotated so it will not trigger the sensor. This means that the polarised reflex can be used to detect very reflective surfaces, even mirrors, polished metal and semi transparent materials. However, the sensing distance is shorter than REFLEX.

Question 11

How can I cable to the PNP and NPN type outputs for sensors / detectors, using the wiring diagram?

Accepted Answer

PNP and NPN type outputs are available as 3-wire sensors with a DC voltage power supply (the voltage limits are dependent on the specific sensor): PNP type: switching on the positive voltage load NPN type: switching on the negative voltage load These outputs are typical of photoelectric detectors, inductive proximity and other types of sensors.For a detailed explanation of PNP vs NPN, see the following FAQ: FA142566 PNP output The load (relay coil, contactor relay input, PLC input) must be connected between the "-" negative terminal and the midpoint. The corresponding PLC input is Sink. NPN output The load must be connected between the "+" positive terminal and the midpoint. The corresponding PLC input is Source. Some sensors have two PNP and NPN outputs (4-wire sensors) which are wired according to the diagram below.Note that we no longer sell sensors. Telemecanique Sensors, who were previously part of the Schneider Electric brand, were sold in 2023. You can go to their website - www.telemecaniquesensors.com - for more information, including contact details.

Question 12

What is the selection criterion of Circuit Breakers for the Capacitor bank application.

Accepted Answer

The selection should be done after derating the Circuit Breaker taking into consideration voltage variation and capacitors tolerances that could increase nominal current up to 1.5In. The Derating factor of 1.5In Where In = Q/ ( Square root of 3 ) Un Q = Capacitor Power Un = Nominal Voltage Choose the Micrologic with delay time selection, so that the Circuit Breaker does not trip due to initial high inrush current. Also to be taken into account are the parameters like supply frequency, operating voltage & harmonics level of the power system for such application. Refer the attached sheet for further details for selection of Circuit Breaker for Capacitor duty application. Note: Use the phase barrier between the phases in Circuit Breaker to prevent flashover due to heavy inrush current.

Question 13

Why is Neutral and Earth (Ground) Connection forbidden Downstream from Main Panel?

Accepted Answer

The question is often asked what is the maximum voltage permitted between the Neutral and Earth (Ground) conductor and if the Neutral and Earth can be bridged to achieve a zero value.This can be a difficult topic, in fact in many cases it can be dangerous. As you will see from the attached document, there are many reasons why it is not allowed.

Question 14

PACTware® - How to update device catalog

Accepted Answer

There are three ways to access the device Catalog in PACTware®: 1. By clicking on the Device Catalog icon: 2. By going to the View menu and clicking on "Device catalog": 3. By pressing F3 on your keypad. While using any of the methods explained above open the Device Catalog, which will be shown on the right of your PACTware® screen. Click on the Update device catalog button. A message will pop up asking if you want to Create new PACTware® device catalog. Say YES by pressing the Yes button: A new message like the one below will be displayed. WAIT until the process is finished. Once the process is completed the pop-up window will automatically disappear, and the Device catalog database will be now be updated. NOTE: If the DTM you are looking for does not appear in the Device Catalog after updating the database, it may indicate that the DTM for your instrument type has not been installed on your computer. If that is the case, - Download the DTM installer from se.com and unzip it to a local folder in your computer. - Close PACTware (PACTware cannot be running while installing your DTM)- Run the installer as an Admin (right click on the file and click on "run as administrator").Once the DTM is installed, open PACTware and update the Database library with the steps explained in this knowledge article. Questions: Help is available at FieldDevices-Support@se.com

Question 15

How do you calculate the wear level of TeSys Giga contactor ? By calculating the on/off time ? Why is opening speed better than opening time ?

Accepted Answer

Contact tips wear rate of is linked to the opening speed and not the opening time. Our algorithm is based on this concept with a dedicated electronic circuit.Arc Voltage is a function of contact separation speed. And Wear Rate is a function of Arc Energy.

Question 16

What are the differences between snap-action and slow-break contacts in limit switches?

Accepted Answer

Note we no longer sell limit switches so the information given below is for information purposes only. You may still be able to buy Telemecanique limit switches (and some 9007 etc. ex-Schneider Electric ranges) but you'd need to go to them directly. This is their website for contact details and product information: www.telemecaniquesensors.com Snap actionThe speed of travel of snap-action contacts is not related to the speed of operation of the actuator. The actuator pretensions an "overcentre spring" mechanism and it is the spring tension which operates the contact once a certain tension has been achieved. This results in a very fast and assured operation of the contacts as the spring mechanisms "flicks" (or "snaps") over the trigger point and latches the contacts on. A similar action takes place on the release, i.e. as the actuator is released the spring tension reduces but the contacts do not move until the tension has dropped below a certain level, when the spring mechanism will snap the contacts open again.Slow BreakA "slow break contact" is one where the physical movement of the actuator is directly linked to the physical movement of the contact. This can give very precise positioning and synchronization of both make and break points but is susceptible to arcing and intermittent signalling at the crucial make/break position, where actuator movement is slow and/or erratic.Main differences between Snap Action and Slow BreakThe snap action contact mechanism inevitably creates a hysteresis effect, where the closing and opening of the switch have considerable overlap. Please see attached timing diagram example. This does not occur with slow break, as the movement of the contacts is directly linked to the movement of the switch / object.Slow break have a higher minimum actuation speed, to overcome the effect of sustain arcing on the contacts. Note that for applications that cause the switch to open a little and then re-close repeatedly / rapidly, this can reduce electrical durability over time.Both types commonly have positive opening N/C contacts (always check your switch to confirm), but snap action provide an assured signal at slower speeds, whereas slow break rely on the minimum actuation speed. This is why there is potential for intermittent signalling on slow break, if that minimum speed is not adhered to.Slow break can often switch bigger loads and offer higher electrical reliability values compared to snap action but please check product tables / data to confirm this on a case-by-case basis.Sequence of moving contactsTiming Sequence for "Snap Action". Note overlap of switching positions for different directions of travel.Timing sequence for "Slow Break". Note same position for make and break.

Support Center

Download Center

Support Center

Download Center

Support Center

Download Center

Products

Support

Company

Quick Links

Partners

Sustainability

Events
opens new tab

FAQ's
opens new tab