Masterpact Maintainence guide
Contents
1. m production losses due to unawareness concerning the status of a circuit breaker m financial losses due to incorrect system management m diagnostic errors m etc Periodic checks on the orders read write commands transmitted by the communication bus are required to maintain a high degree of reliability and confidence in the communication system 1 For more information contact your Schneider Electric after sales support department Schneider Electric P427002A 28 PB100786A 40 Masterpact NT and NW Masterpact NT and NW Maintenance gulde What must be maintained and why Connections The connections between the various distribution systems in a switchboard busbars cables and the switchgear are a major source of heat loss Incorrect tightening may lead to thermal runaway which in turn can provoke damage to the device the cable insulation and even result in a short circuit and or a fire This type of malfunction is often due to disregard for installation requirements during switchboard assembly Note connections must never use different materials copper aluminium m Sliding connections chassis They are made up of two parts the clusters and disconnecting contacts This type of connection is critical and requires periodic cleaning in compliance with the described procedures The grease facilitates the connection between the clusters and the disconnecting contacts and avoids damaging the silver coated surface by r2. Solutions o disable the locking fonction o check the position of the other circuit breaker in the changeover system o modify the situation to release the interlock o terminate racking in connection of the circuit breaker o clear the fault O push the reset button on the front of the circuit breaker o charge the mechanism manually o ifitis equipped with aan MCH gear motor check the supply of power to the motor If the problem persists replace the gear motor MCH o there is an opening order Determine the origin of the order The order must be cancelled before the circuit breaker can be closed o there is an opening order Determine the origin of the order o check the voltage and the supply circuit U gt 0 85 Un Ifthe problem persists replace the release o cutthe supply of power to the XF closing release then send the closing order again via the XF but only if the circuit breaker is ready to close o Disable these protection functions on the Micrologic P or H control unit Circuit breaker cannot be closed remotely but can be opened locally using the closing pushbutton m Closing order not executed by the XF closing release o check the voltage and the supply circuit 0 85 1 1 Un If the problem persists replace the XF release Unexpected tripping without activation of the reset button signalling a fault trip m MN undervoltage release supply voltage too low m Load shedding order sent to the M
3. 303 14 304 49 NO Corrosion of metal parts Oxidation Increased temperature rise 3C1 0 052 Nitrogen oxide 3C2 0 26 3C3 1 56 3C4 5 2 Oily atmospheres Attacks polycarbonates Cracking of polycarbonates Risk of rupture Increased temperature rise Class Environment categories as per standard 721 3 3 Urban zones with scattered industrial activity and heavy traffic Rural zones or urban zones with low industrial activity Immediate vicinity of industrial pollution Example paper mills water treatment chemicals synthetic fibres smelting plants Inside polluting industrial premises Example paper mills water treatment chemicals synthetic fibres smelting plants Presence of corrosive gases Impact on switchgear No impact on service life because concentrations are very low Moderate impact on service life Major impact particularly concerning temperature rise For electronic systems no impact on varnished boards and gold plated contacts Significantly reduced service life if no particular precautions are taken For electronic systems no impact on varnished boards and gold plated contacts Preventive maintenance Implement the standard program Implement the standard program PYRATEX grease can be used for the disconnecting contacts but must be changed annually see the manufacturer procedure Carry out more frequent periodic checks see page 10 Change the grease
4. electrical reset Hardening of glues Visual Loss of labels Deterioration of electronic components Modified display of LCDs Loss of display Nuisance tripping or no tripping Deterioration of opto electronic devices and SCRs Not identifiable Possible transmission of erroneous orders Loss of battery backup power Not identifiable Fault indications not displayed 25 C 25 35 C 35 45 C Optimum operating conditions A10 C increase in the ambient temperature A20 C increase in the ambient temperature is is equivalent to a5 increase inthe percent equivalent to a 10 increase in the percent load load Preventive maintenance Implement the standard program Carry out more frequent periodic checks Carry out more frequent periodic checks see page 10 see page 10 Installation No particular precautions required No particular precautions required Install forced air ventilation in the switchboard or air conditioning for the electrical room 1 Example A 100 A device with an 80 load with an annual average ambient temperature of m 25 will have a service life of approximately 30 years m 35 C will have a service life of approximately 27 years m 45 will have a service life of approximately 25 years LVPED508016EN 11 2008 Schneider 15 DB109068 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Percent load I In Influence Appearance Consequences Note The percent l
5. from seaside Rapid ageing of exposed switchgear On average service life is divided by a factor of three for non protected devices Carry out more frequent periodic checks see page 10 Test the dielectric withstand every two years Switchgear must be protected from salt mist Increase the switchboard IP value IP54 is advised Create a protected room k Schneider LVPED508016EN 11 2008 DB101521 DB101522 Masterpact NT and NW Maintenance guide Influence Increase in skin effect proximity effect iron losses Foucault currents Harmonics Appearance grease Modified display of LCDs Change in colour of terminals insulators and Causes of accelerated ageing Consequences Harmonics cause temperature rise greater than that of the fundamental current Possible overload of neutral if third order harmonics and their multiples are present Distorted waveform Erroneous current value Nuisance tripping if non rms trip units THDi lt 30 No notable influence on ageing Preventive maintenance Implement the standard program Installation No particular precautions required THDi 30 to 50 At 40 THDI heat loss is approximately 10 higher corresponding to 5 more current Carry out more frequent periodic checks see page 10 Standard filtering with an inductor to reduce THDi gt 50 Carry out more frequent periodic checks see page 10 If necessary ove
6. of connectors on large Not identifiable Failure of protection function electronic components e g large capacitors Wear ofthumbwheel contacts on the Not identifiable Nuisance tripping or no tripping control unit 0 2g 0 2gto0 5g 0 5 gto 0 7 g gt 0 7g Normal condition no impact on Reduced service life Significant increase in incidents Forbidden for standard devices service life Preventive maintenance Implement the standard program Carry out more frequent periodic Carry out more frequent periodic checks see table checks see page 10 Check in particular the tightness of connections No particular precautions required No particular precautions required Install switchgear on a rubber Use special devices mounting bush Number of operating cycles Influence Appearance Consequences The number of operating cycles depends directly on Device service life depends on the daily number of the electrical and mechanical endurance of the operating cycles device Device service life depends on the daily number of operating cycles lt 30 cycles per month lt 60 cycles per month 120 cycles per month Corresponds to one cycle per day Corresponds to two cycles per day Corresponds to four cycles per day For an endurance of 10000 cycles and an For an endurance of 10000 cycles and an For an endurance of 10000 cycles and an interrupted current of less than 0 4 In the service interrupted current of less than 0 4 In the service inter
7. on the disconnecting contacts Carry out more frequent periodic checks see page 10 Change the grease on the disconnecting contacts Installation No particular precautions required Use fixed rather than drawout devices No particular precautions required It is advised to install the switchgear in a room protected from the pollution Use fixed rather than drawout devices or implement special solutions gold plated disconnecting contacts 1 ppm Parts Per Million Schneider 21 Electric LVPED508016EN 11 2008 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Operating conditions Operating conditions directly affect the service life of switchgear due to the limited electrical and mechanical endurance levels of the various subassemblies Operating conditions include m vibrations m the number of operating cycles m the interrupted currents Vibrations Influence Appearance Consequences Premature deterioration of contact Not identifiable Increased device temperature rise surfaces clusters and main contacts Untightening of bolted assemblies Not identifiable Increase in mechanical play Wear of mechanical parts Not identifiable Broken springs Increase in mechanical play between parts Appearance of fretting corrosion on Not identifiable Erroneous information or loss of continuity in data or supply excessive auxiliary connections temperature rise Breaking
8. u m m Tester auxiliaires NIII_2_6 pdf Check tripping curves using test tool signallling LED a m m FFIK control unit NIII_2_1 pdf tripped overload FFTK report generator software Save results on PC Dust and regrease chassis u m m Mobilith SHC100 chassis NIII_2_1 pdf Regrease disconnecting contact clusters specific case of m m Mobilith SHC100 chassis NIII_2_2 pdf corrosive athmospheres Check and tighten loose connections Only after a visual Dynamometric crank power connections NIII_2_1 pdf inspection showing overheating marks 1 These checks and tests will be carried out by Schneider Electric Services in case of diagnostic the fifth year see page 14 wo LVPED508016EN 11 2008 Schneider 1 rel NT Nw Level IV manufacturer diagnostic N and replacement of components recommended every 5 years Level IV All the major preventive and corrective maintenance work ensured by the Schneider Electric after sales support department Procedure number S internal use Measure insulation resistance m Ohmmeter device NIV_3_1 pdf Check tripping forces crescent shaped part m Tester mechanism NIV_3_1 pdf Measure resistance of input output contact m Ohmmeter injection unit breaking unit NIV_3_1 pdf Check the service life of the auxiliaries XF MX MN m service life software auxiliaries NIV_3_1 pdf Preventitive replacement of control auxiliaries None Save protection settings log event
9. 43717AA AO m chassis accessories m chassis accessories 51201112AA AO 04443718AA A0 51201115AA A AC 04443719AA A Micrologic A 04443723AA B DC En 04444163AA_B1 Micrologic P 04443725AA A Micrologic H En Fr 510051284AAA En Fr 510051284AAA En Fr 510051284AAA FIMNT FIMNW FIM NT amp FIM NW Schneider Electric after sales Schneider Electric after sales Schneider Electric after sales support only support only support only See User manual 51201115AA A See User manual 04443719AA A COMBT15EN COMBT15EN COMBT15EN 48049 183 01 oa LVPED508016EN 11 2008 Schneider 2 Masterpact NT and NW Maintenance guide Problem Circuit breaker cannot be closed locally or remotely Troubleshooting and solutions Probable causes m Circuit breaker padlocked or keylocked in the open position m Circuit breaker interlocked mechanically in a source changeover system m Circuit breaker not completely connected m The reset button signalling a fault trip has not been reset m Stored energy mechanism not charged m MX opening shunt release permanently supplied with power m MN undervoltage release not supplied with power m XF closing release continuously supplied with power but circuit breaker not ready to close XF not wired in series with PF contact m Permanent trip order in the presence of a Micrologic P or H control unit with minimum voltage and minimum frequency protection in Trip mode and the control unit powered
10. 5 H1 H2 H3 10000 20000 NW10N H 10000 20000 NW20 L1 10000 20000 NW20N H 10000 20000 NW32 to NW 40 H1 H2 H3 10000 20000 NW40N H 10000 20000 NW40b to NW63 H1 H2 5000 10000 1 Number of device operating cycles without maintenance 2 Number of device operating cycles with maintenance The elements below must be replaced during the device service life to reach the maximum possible number of operating cycles arc chutes main contacts connecting rod springs MCH gear motor interlocks MX XF MH control auxiliaries In case of contact swear all contacts must be changed the complete breaking block is then replaced Arc chutes at In NTO8 to 10 440 V H1 6000 NW08 to NW16 N1 H1 H2 10000 500 V DC NTO8 to 10 690 V H1 3000 NW08 to NW16 L1 3000 NW10N H 8500 NT12 440 VH1 6000 NW20 to NW25 440 V H1 H2 8000 NW20 N H 5000 NT12 690 V H1 3000 NW20 to NW25 690 V H1 H2 6000 NW40 N H 2000 NT16 440 V H1 3000 NW20 to NW25 H3 2000 900 V DC NT16 690 V H1 1000 NW20 to NW25 690 V H1 H2 H3 6000 NW10 N H 2000 NTO8 to 10 440 V L1 3000 NW20 L1 3000 NW20 N H 2000 NTO8 to 10 690 V L1 2000 NW32 to NW40 440 V H1 H2 5000 NW40 N H 1000 NW32 to NW40 690 V H1 H2 2500 NW32 to NW40 690 V H3 1250 NW40b to NW63 H1 H2 1500 Main contacts at In NTO8 to 10 440 V H1 6000 NW08 to NW16 N1 H1 H2 10000 500 V DC NT08 to 10 690 V H1 3000 NW08 to NW16 L1 10000 NW10 N H 8500 NT12 440 V H1 6000 NW20 to NW25 440 V H1 H2 H3 8000 NW20 N H 8500 NT12 690 V H1 3000 NW20 to NW25 690
11. Low voltage electrical distribution Masterpact NT and NW Circuit breakers and switch disconnectors Maintenance guide 11 2008 f Schneider This guide is intended primarily for qualified personnel in charge of equipment maintenance and for Schneider Electric after sales support personnel for the information on system diagnostics Thank you for purchasing a Merlin Gerin protection device To maintain the device s operating and safety characteristics as they are indicated in the catalogue from the beginning to the end of the product s service life Schneider Electric recommends that systematic checks and periodic maintenance be carried out by qualified personnel as indicated in this Masterpact maintenance Please read this document carefully and keep it at hand near the device It provides detailed information on m the various types of maintenance required depending on the criticality of the protected circuit m what must receive maintenance m the risks involved if the component ceases to operate correctly m what is understood by the terms normal improved and severe environment and operating conditions m the periodic preventive maintenance operations that should be carried out under normal environment and operating conditions as well as the level of competence required for the operations m the environment and operating conditions that accelerate device ageing m the limits governing use of mechanical and elec
12. Serenity service Percent load Estimate as precisely as possible the probable Remote monitoring by service life ofthe device m customer supervisor or m Serenity service Pole opening and closing speed Monitor any mechanical drift in devices and Prodiag tester Remote monitoring by evaluate their condition m customer supervisor or m Serenity service 1 Serenity is a Schneider Electric service providing installation diagnostics and analysis of distribution systems For more information on the possibilities offered by predictive maintenance contact your Schneider after sales support department LVPED508016EN 11 2008 Schneider 3 53341A 56 PIC00002A 40 DB104447A Masterpact NT and NW Maintenance guide Kill 4 Schneider Electric Masterpact NT and NW What must be maintained and why The case The case is an essential element in the circuit breaker First of all it ensures a number of safety functions m functional insulation between the phases themselves and between the phases and the exposed conductive parts in order to resist transient overvoltages caused by the distribution system m a barrier avoiding direct user contact with live parts m protection against the effects of electrical arcs and overpressures caused by short circuits Secondly it serves to support the entire pole operating mechanism as well as the mechanical and electrical accessories of the circuit breaker On the case there sho
13. V H1 H2 H3 6000 NW40 N H 4000 NT16 440 V H1 3000 NW20 L1 10000 900 V DC NT16 690 V H1 1000 NW32 to NW40 440 V H1 H2 H3 5000 NW10 N H 2000 NTO8 to 10 440 V L1 3000 NW32 to NW40 690 V H1 H2 H3 2500 NW20 N H 2000 NTO8 to 10 690 V L1 2000 NW40b to NW63 H1 H2 3000 NW40 N H 2000 Connecting rod springs gear motor interlocking mechanisms All ratings 12500 NW08 to NW16 N1 H1 H2 12500 500 V DC 900 V DC and performance levels NWO to NW16 L1 12500 NW10N H 10000 NW20 to NW40 H1 H2 H3 10000 NW20 N H 10000 NW20 L1 10000 NW40 N H 10000 NW40b to NW63 H1 H2 5000 MX XF MN control auxiliaries All ratings 12500 All ratings and performance levels 12500 500 V DC 900 V DC and performance levels NW10N H 12500 NW20 N H 12500 NW40 N H 12500 24 Schneider LVPED508016EN 11 2008 Electric Masterpact NT and NW List of available guides Maintenance guide Switchgear guides Masterpact NT Masterpact NW Micrologic A P H NT PAR NW PAR NT PAR amp NW PAR Schneider Electric after sales Schneider Electric after sales Schneider Electric after sales support only support only support only LVPED205008EN LVPED205008EN LVPED205008EN Maintenance 15 03 Maintenance 15 03 Maintenance 15 03 Schneider Electric after sales Schneider Electric after sales Schneider Electric after sales support only support only support only m circuit breaker 51201003AA A1 m circuit breaker 51156118AA AO m circuit breaker accessories m circuit breaker accessories 51201111AA AO 044
14. X opening release by another device m Unnecessary opening order from the MX opening release o check the voltage and the supply circuit U gt 0 85 Un o check the overall load on the distribution system o if necessary modify the settings of devices in the installation o determine the origin of the order Unexpected tripping with activation of the reset button signalling a fault trip A fault is present m overload m earth fault m short circuit detected by the control unit o determine and clear the causes of the fault o check the condition of the circuit breaker before putting it back into service Instantaneous opening after each attempt to close the circuit breaker with activation of the reset button signalling a fault trip m Thermal memory m Transient overcurrent when closing m Closing on a short circuit o see the user manual of the control unit D press the reset button O modify the distribution system or the control unit settings o check the condition of the circuit breaker before putting it back into service D press the reset button o clear the fault o check the condition of the circuit breaker before putting it back into service D press the reset button 26 Schneider Electric LVPED508016EN 11 2008 Masterpact NT and NW Maintenance guide Problem Circuit breaker cannot be opened remotely but can be opened locally Probable causes Troubleshooting and solutions Solutio
15. ach five year period the maintenance guide must be systematically repeated These maintenance operations apply for normal operating and environment conditions as defined below Normal operating and environment conditions Temperature oe annual temperature lt 25 C outside the switchboard Ta Percent load lt 80 of In 24 24 hours Harmonics Harmonic current per phase lt 30 of In Relative humidity lt 70 Corrosive atmosphere Device installed in environment category 3C1 or 3C2 IEC 60721 3 3 Salt environment No salt mist Dust Low level Device protected in switchboard equipped with filters or ventilated IP54 enclosure Vibration Permanent vibration lt 0 2 g Beyond the above limits the circuit breakers suffer accelerated ageing that may rapidly result in malfunctions For this reason periodic checks must be carried out at shorter time intervals On the other hand when special efforts are made to improve the operating and environment conditions the preventive maintenance operations can be carried out less often 1 The Masterpact maintenance guide is taken into account by the Schneider Electric CamSoft software Example of a maintenance plan managed by CamSoft 04448A 103 Sf Schneider Electie Schneider 9 Electric PB100786A 40 041201A 66 Masterpact NT and NW Maintenance guide 10 Schneider Electric Recommended preventive maintenance and time interv
16. al impact on ageing components Preventive maintenance Implement the standard Carry out more frequent Preventive maintenance is Carry out more frequent Preventive maintenance is program periodic checks difficult due to the periodic checks difficult due to the continuous see page 10 continuous process see page 10 process Inspect for condensation Plan more frequent periodic checks Installation Normal conditions Provide ventilation for the Spread the load over other switchboard outgoers Install a device with a higher rating fe Beecte rents Sec uel pump N 1 PMO IA um Pow Epwi THD Micet Contat 16 Schneider LVPED508016EN 11 2008 046356A 66 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Relative humidity Influence Appearance Consequences Corrosion of metal surfaces that is accelerated Appearance of Increase in friction when a pollutant is present corrosive gas salt m red ruston iron Risk of mechanical rupture resulting in non chlorine etc m white rust on zinc operation of mechanisms m blue deposit on copper Increase in contact resistance clusters and main m black deposit on silver contacts Deterioration of dielectric qualities of plastics White traces on case Risk of a reduction in insulation Deterioration of electronic components in particular Not visible Short circuiting of circuits resulting in non SMCs and silver coated componen
17. als Favourable conditions or device protected The time interval between two preventive maintenance visits can be doubled if all the conditions presented below are met The only exception is the check up program recommended for the 5 year Favourable operating and environment conditions or device Temperature Average annual temperature lt 25 C outside the switchboard Ta The device is installed in an air conditioned room or in a ventilated enclosure Percent load lt 50 of In 8 24 hours or 24 24 hours Relative humidity lt 50 Corrosive atmosphere Device installed in environment category 3C1 or in a protected room air is conditioned and purified Salt environment None Dust Negligible Device protected in switchboard equipped with filters or ventilated IP54 enclosure Vibration None 1 Ti Ta see the definition in the Masterpact catalogue Example depending on the conditions m normal check on charging time 2 years m favourable check on charging time 2x2 4 years Severe conditions and device not protected The time interval between two preventive maintenance visits must be reduced by half if any of the conditions presented below are present Severe operating and environment conditions Temperature Average annual temperature between 35 and 45 C around the annual average switchboard see definition in EN 60439 1 Percent load gt 80 of In 8 24 hours or 24 24 hours Rela
18. cted position and the reset button out o pull the rails all the way out Circuit breaker cannot be connected racked in m Cradle circuit breaker mismatch protection m The safety shutters are locked m The disconnecting contact clusters are incorrectly positioned m Cradle locked in disconnected position m The reset button has not been pressed preventing rotation of the crank m The circuit breaker has not been sufficiently inserted in the cradle o check that the cradle corresponds with the circuit breaker o remove the lock s o reposition the clusters O disable the cradle locking function D press the reset button o insert the circuit breaker completely so that it is engaged in the racking mechanism Circuit breaker cannot be locked in disconnected position m The circuit breaker is not in the right position m The cranck is still in the cradle o check the circuit breaker position by making sure the reset button is out o remove the crank and store it Circuit breaker cannot be locked in connected test or disconnected position m Check that locking in any position is enabled m The circuit breaker is not in the right position m The cranck is still in the cradle o contact a Schneider service centre o check the circuit breaker position by making sure the reset button is out o remove the crank and store it The crank cannot be inserted to connect or disconnected the circuit breaker m The rails are no
19. ducts under pressure or containing solvents trichloroethane trichloroethylene is strictly forbidden e g WD40 The main problems of products under pressure are the following o it may be impossible to regrease inaccessible lubrication points greased for the life of the product o corrosion of points that are not regreased o damage caused by the pressure of the product o risk of temperature rise due to the presence of an insulating solvent in the contact zones o elimination of special protection o deterioration of plastic materials m Greasing This operation is carried out after cleaning on certain mechanical parts as described in the maintenance procedures using the various greases recommended by Schneider Electric Grease must not be over applied because the excess if mixed with dust may result in mechanism malfunctions Generally speaking under normal operating conditions the pole operating mechanism does not require any regreasing greased for the life ofthe product O The clusters and disconnecting contacts must be greased according to the defined intervals using the greases indicated by Schneider Electric o The main contacts must not be greased Operating cycles The imperative need to ensure continuity of service in an installation generally means that power circuit breakers are rarely operated If on the one hand an excessive number of operating cycles accelerates device ageing it is also true that a lack of opera
20. educing the racking in friction In sulphurous corrosive atmospheres H2S SO it is necessary to implement the cleaning procedure using the Thiourea solution with mandatory regreasing using the specified fluorinated grease This type of grease protects the silver and copper coated contacts against sulphuration Because silver or copper sulphide being insulating it provokes an increase in the contact resistance and thus greater temperature rise The grease breaks down over time and it is therefore necessary to replace it regularly m Fixed connections Connections using lugs or bars When made in compliance with Schneider Electric recommendations tightening torque 8 8 hardware and contact washer this type of connection does not require any particular maintenance Otherwise regularly check the temperature rise points change in colour of copper or tinning dismantle the connections clean and scrape the contact surfaces then reassemble the connections using new hardware Check the terminals 8 Schneider LVPED508016EN 11 2008 Electric Masterpact NT and NW Maintenance guide LVPED508016EN 11 2008 Recommended preventive maintenance and time intervals Normal conditions The maintenance guide that must be carried out every one two or five years on Masterpact NT NW subassemblies and the level of competence required on the part of service agents are described in the tables on pages 12 13 and 14 At the end of e
21. es Increase in racking forces exerted Increased contact resistance and temperature rise Deposit on displays Screen data not legible Deposit on insulation Reduced insulation resistance depends on type of dust This phenomenon is worsened by the presence of humidity Deposit on device contacts Increased contact resistance and temperature rise Deposit on opto electronic communication system between devices Low level Moderate Quantity of dust generally deposited on and around Quantity of dust found in protected switchboards devices in commercial buildings and on standard installed in dusty environments such as cement industrial premises works grain mills incineration installations plastic and steel mills mines etc Failure of communication data transmission High Quantity of dust deposited on and around devices inside non protected switchboards installed in dusty environments such as cement works grain mills incineration installations plastic and steel mills mines etc Preventive maintenance Implement the standard program Carry out more frequent periodic cleaning It is advised to vacuum cleaner dust deposits see table 10 Installation Switchboard with standard IP Make sure the switchboard remains closed Carry out more frequent periodic cleaning see table 10 Special equipment required to protect the switchgear is mandatory a Schneider LVPED508016EN 11 2008 Masterpac
22. f 1 These checks will be carried out by Schneider Electric Services in case of diagnostic the fifth year see page 14 2 Schneider LVPED508016EN 11 2008 ate NT a NW Level Ill preventive maintenance la recommended every 2 years Level Ill General preventive maintenance operations such as general adjustments trouble shooting and diagnosis of breakdowns repairs by exchange of components or functional parts minor mechanical repairs carried out by a qualified customer technician using the tools and measurement setting devices specified in the manufacturer maintenance instructions Procedure number Check gear motor charging time at 0 85 Un E m m Stop watch external mechanism NIII_2_1 pdf power supply Check general condition of mechanism m m Screwdriver mechanism NIll_2_2 pdf Check condition of breaking unit m Screwdriver breaking unit NIII_2_1 pdf Check operation of indication contacts m m Qmetre auxiliaries NIII_2_1 pdf OF PF MCH Check closing operation of control auxiliary m m External power supply auxiliaires NIII_2_2 pdf XF at 0 85 Un Check opening operation of control auxiliary E m m External power supply auxiliaires NIII_2_3 pdf MX at 0 70 Un Check operation of control auxiliary MN MNR between a m m External power supply auxiliaries NIII_2_4 pdf 0 35 and 0 7 Un Check delay of MNR devices at 0 35 and 0 7 Un u m m External power supply auxiliaires NIII_2_5 pdf Check MX tripping time
23. ive maintenance alea B Sampling Mode MANUAL Ssecondss zi Predictive maintenance based on the recording and analysis of system parameters is the means to detect drift from the initial state and significant trends Using ime vent lodule F P m Fer am was einem ca a aee LL predictive maintenance the customer can anticipate on the corrective action Scie man Dalek vr tt Ama required to ensure equipment safety and continuity of service and plan the action for Go an Sa he most convenient time u ah ae Br 2 eig To ensure the highest possible level of installation reliability and optimise the service ae ii Be ec BEIR DE life of equipment it is advised to establish a maintenance plan Kam WR gen PERN oe vum sist Be Ue y a lapse The plan indicates for each piece of equipment Sie u BETee cuna Tree A m the most suitable type of maintenance Bee re AE E an Gama h ded fi f mai e sabes cea ea meas ee E m the recommended frequency of maintenance on Pen Se erate The plan is based on two criteria a MAR Aaah Sea a vet ee E Hosen et a A nel m the criticality of each device in the installation Ready ONLINE DEMO No working system 9 30 o m device operating conditions Criticality depends on the consequences of device failure in terms of the safety of life and property production losses the cost of repair and start up etc An empirical estimate may be sufficient for simple cases but it is recommended to unde
24. l conditions overloads and short circuits The contacts are eroded by the many opening and closing cycles and can be particularly deteriorated by short circuit currents Worn contacts may result in abnormal temperature rise and accelerate device ageing It is imperative to remove the arc chutes and visually check contact wear at least once a year and following each short circuit The contact wear indicators constitute an absolute minimum value that must not be overrun To plan and reduce the number of shutdowns an electronic wear counter is available with the Micrologic P and H A visual check is required when the counter reaches 100 When the counter reaches 300 the contacts must be replaced LVPED508016EN 11 2008 PB100766A 56 PB100764A 56 Masterpact NT and NW Maintenance guide LVPED508016EN 11 2008 Masterpact NT and NW What must be maintained and why Device and chassis mechanisms Mechanical operation of the circuit breaker may be hindered by dust knocks aggressive atmospheres no greasing or excessive greasing Operating safety is ensured by dusting and general cleaning proper greasing and regular opening and closing of the circuit breaker Dusting Dusting is best carried out using a vacuum cleaner m Cleaning Cleaning should be carried out using a cloth or brush that is perfectly clean and dry without using any solvents avoiding greased parts except for grease on electrical contacts Application of pro
25. ns m Opening order not executed by the MX opening o check the voltage and the supply circuit release m Opening order not executed by the MN undervoltage release 0 7 1 1 Un If the problem persists replace the MX release o drop in voltage insufficient or residual voltage gt 0 35 Un across the terminals of the undervoltage release If the problem persists replace the MN release Circuit breaker cannot be opened locally m Operating mechanism malfunction or welded contacts o contact a Schneider Electric service centre Circuit breaker cannot be reset locally but not remotely m Insufficient supply voltage for the MCH gear motor o check the voltage and the supply circuit 0 7 1 1 Un If the problem persists replace the MCH release Nuisance tripping of the circuit breaker with activation of the reset m Reset button not pushed in completely button signalling a fault trip D push the reset button in completely Impossible to insert the crank in connected test or disconnected m Apadlock or keylock is present on the chassis position or a door interlock is present o disable the locking function Impossible to turn the crank m The reset button has not been pressed O press the reset button Circuit breaker cannot be removed from chassis m Circuit breaker not in disconnected position m The rails are not completely out o turn the crank until the circuit breaker is in disconne
26. oad affects the device temperature which is itself affected by the ambient temperature Ageing of plastic insulation Change in colour of insulation Breaking of parts leading to failure of functions Ageing of grease Change in colour and viscosity Increase in mechanical friction Ageing of electronic components Modified display of LCDs A 10 C increase i e an 85 percent load cuts the service life of components by approximately half Deterioration of characteristics Rupture Non operation of mechanisms m steel springs above 100 C m stainless steel springs above 200 C lt 80 24 24 hours lt 90 8 24 hours lt 90 24 24 hours In 8 24 hours In 24 24 hours Maximum percent load At this percent load The thermal stress for Between 90 and 100 Between 90 and 100 generally taken into accountin temperature rise is reduced continuous operation is temperature rise is close to temperature rise is close to its sizing the installation At this only 20 Heating and three times higher than in its maximum value Heating maximum value percent load temperature rise cooling cycles impact on the the previous case but the and cooling cyclesimpacton This situation has a major is reduced approximately 40 mechanical junctions of the absence of thermal cycles the mechanical junctions of impact on ageing It is not with respect to a 100 percent power circuit slows ageing of the the power circuit with major recommended load electromechanic
27. oduct maintenance recommendations are laid out by the technical department These verification procedures intended to maintain systems or their subassemblies in correct operating condition over the targeted service life must be carried out according to the time intervals stipulated in this document Under no circumstances can Schneider Electric be held responsible for any damage caused by the failure of device if the periodic checks were not carried out in accordance with the recommendations in this document m Conditional maintenance To a certain extent conditional maintenance operations are ameans to reduce but not eliminate the recommended periodic maintenance operations thus limited to 6 l l DB120071A Kane angen Be eee oe Fr the strict minimum that require an annual shutdown of the installation aaa These operations are launched when programmed alarms indicate that a predefined threshold has been reached To that end sensors must be installed on the switchgear and in the switchboard Conditional maintenance is the means to optimise installation maintenance For more information on the possibilities offered by conditional maintenance contact your Schneider Electric after sales support department 2 Schneider LVPED508016EN 11 2008 Electric DB101523 Masterpact NT and NW The different types Maint id u nn of maintenance Mi POWERLOGIC S M Dem BEE H H H TEE Predict
28. ondition ofthe device escutcheon control unit case chassis connections Open close device manually and electrically m u m m None mechanism NII_1_1 pdf Charge device electrically Eu m m None mechanism NIl_1_2 pdf Check complete closing of device s poles m m None mechanism NIl_1_3 pdf Check number of device operating cycles m m m m Operation counter mechanism NII_1_4 pdf Check the filters cleanlines and the fixing of the arc chute m Dynamometric crank breaking unit NII_1_1 pdf Check auxiliary wiring and insulation m m m m None auxiliaries NII_1_1 pdf Trip control unit using test tool and check operation of contacts m HHTKouFFTK control unit NII_1_1 pdf SDE1 and SDE2 Check earth fault protection function Micrologic 6 0 or m m m m None control unit NII_1_2 pdf earth leakage protection function Micrologic 7 0 Open and close keylocks installed on device m m m m None device locking NII_1_1 pdf Open and close padlocking system installed on device m m m m None device locking NII_1_2 pdf Remove device from chassis and put it back m m m None chassis NII_1_1 pdf Check operation of position contacts CE CT CD EF m m m None chassis NII_1_2 pdf Check operation of safety shutters m m m None chassis NII_1_3 pdf Open and close keylocks installed on chassis m m m None chassis locking NII_1_1 pdf Operate padlocking system u u m m None chassis locking NII_1_2 pd
29. r motor wears quickly Periodic checks on gear motor operation and the charging time are required to ensure the device closing function 1 For more information contact your Schneider Electric after sales support department LVPED508016EN 11 2008 056490A 58 PB100802A 24 056461NA 56 Masterpact NT and NW Maintenance guide LVPED508016EN 11 2008 Masterpact NT and NW What must be maintained and why Electronic trip unit If an electric fault occurs in the installation the electronic trip unit detects the fault and orders the circuit breaker to open and thus protect life and property Electronic components and circuit boards are sensitive to the environment ambient temperature humid and corrosive atmospheres and to severe operating conditions magnetic fields vibrations etc To ensure correct operation it is necessary to periodically check the chain of action resulting in a trip the response time as a function of the level of the fault current Depending on the operating and environment conditions it is advised to estimate their service life using the service life software and to replace them if necessary to avoid any risk of non operation when they are needed Communication module and accessories Via the communication bus the communication option transmits data to a remote site for use by various departments maintenance management production etc Abreak in the transmission of data can result in
30. rating cycles Interrupted current Operating limits List of available guides Switchgear guides Troubleshooting and solutions Schneider Electric WOM Nh NY ONNOOAAR A Masterpact NT and NW The different types Maintenance guide o of maintenance Corrective maintenance Corrective maintenance repairs a system in view of fulfilling a required function gt Incidents during system start up Many malfunctions result from non observance of the start up instructions or lack of O knowledge concerning the equipment and or switchgear procedures Schneider Electric operating guides supplied with products and equipment contain clear instructions for operators or maintenance personnel on how to correct malfunctions These instructions are included at the end or this guige The list of the available operating guides may be found at the end of this document The PDF files may de downloaded from the www schneider electric com site Breakdowns during operation Contact the certified maintenance department The Schneider Electric Service Centres may be contacted via the www schneider electric com site Preventive maintenance Preventive maintenance consists in carrying out at predetermined intervals or according to prescribed criteria checks intended to reduce the probability of a failure or deterioration in the operation of a system There are two types of preventive maintenance m Periodic maintenance For each type of pr
31. rsize the neutral harmonics Oversize switchgear Filtering is mandatory FG POWERLOGIC System Manager Demo BEE 9 File Edit View Setup Control Display Reports Tools Window Help ox S ely 9 a Sampling Mode MANUAL Sseconds Sea Time Event Module Phase A N Voltage Harmonics Analysis o Fundamental Lie T H2 H3 H4 H5 H6 H7 H8 Harmonics H9 H10 H11 H12 E Ready ONLINE DEMO No working system 9 30 O 4 POWERLOGIC System Manager Demo BEE amp Eile Edit View Setup Control Display Reports Tools Window Help lelx s 2x 8 al Sampling Mode MANUAL BEE Fundamental RMS RMS H Your Specific Device Phase A N Voltage 118 08 118 11 2 38 166 86 1 41 Harmonics RMS Ready ONLINE DEMO No working system 9 30 o LVPED508016EN 11 2008 Schneider 19 Electric 027488A 66 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Dust Influence Appearance Deposit on grease of mechanisms Change in colour and texture of greases device and chassis Consequences Premature wear of mechanisms because dust mixed with grease can be abrasive Increase in mechanical friction and freezing of moving parts Risk of device not moving on chassis Risk of device non opening or non closing Deposit on grease of clusters Change in colour and texture of greas
32. rtake a reliability analysis of the installation for more complex architectures involving backup sources transfer mechanisms etc Check with your Schneider Electric Service Centre for more information The operating conditions reflect the environment in which the device is installed relative humidity heat dust etc and how the device is used load frequency of operation quality of the supply current etc These conditions are discussed in detail in this document as well as the ensuing maintenance recommendations Consequently for a given device the recommended maintenance may vary substantially both in terms of the necessary operations and their frequency Example of Masterpact predictive maintenance Number of operating cycles Monitor manufacturer limits and determine the Electronic counter with the Remote monitoring by probable replacement date communication module m customer supervisor or MPS100 server m Serenity service Trip and alarm histories Analyse the distribution system phenomena that Micrologic P H event log Remote monitoring by resulted in tripping or alarms caused by transient MPS100 server m customer supervisor or overloads setting changes or a modification in the m Serenity service installation Contact wear Monitor without dismantling the arc chutes on the Micrologic P H event log Remote monitoring by circuit breakers and plan their replacement MPS100 server m customer supervisor or m
33. rupted current of less than 0 4 In the service life is 27 years life is 13 years life is 7 years 22 Schneider LVPED508016EN 11 2008 PIC00027A 56 PIC00005A 56 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Interrupted current Influence Appearance Consequences Wear of fixed and moving contacts Deterioration of contacts Beyond the electrical endurance limit device temperature rise increases due to the greater contact resistance and a reduction in the pressure of contacts Wear of the arc chutes insulating materials Deterioration of insulation Beyond the electrical endurance limit the insulation separators input output and between phases is reduced which results in a reduction of device suitability for isolation In this case the safety of persons is no longer guaranteed 0 4 In 0 8 In s In This level of interrupted current corresponds to the This level of interrupted current corresponds to This level of interrupted current corresponds to the mechanical durability approximately 125 ofthe electrical durability electrical durability at the specified voltage see Mechanical endurance see Electrical endurance LVPED508016EN 11 2008 Schneider 23 Masterpact NT and NW Operating limits Maintenance guide Maximum number of opening closing cycles no load All ratings 12500 NWO to NW16 N1 H1 H2 L1 12500 25000 500 VDC 900 VDC and performance levels NW20 to NW2
34. s Micrologic P and H E E Magicbox SSU software control unit NIV_3_1 pdf and edit reports Check continuity of the tripping chain by primary injection m u m Injection unit control unit NIV_3_2 pdf for each phase Check DIN DINF tripping using performer test tool m m m m Performer test kit control unit NIV_3_3 pdf Check operation of thumbwheels u u m m RSU control unit NIV_3_4 pdf Check the service life of control unit m 8 m m service life software auxiliaries NIV_3_1 pdf Preventitive replacement of Micrologic RSU control unit NIV_3_5 pdf Check connection disconnection torque m m m m Dynamometric crank chassis NIV_3_1 pdf Clean and regrease racking screw NW only m m m m Grease chassis NIV_3_2 pdf Test the device control the uploading of contact status m m m Magicbox RCU software communication en NIV_3_1 pdf OF SDE PF CH operation of optical link by using the communication Bus Test the uploading of chassis position contacts the m m m m Magicbox RSU software communication en NIV_3_2 pdf synchronisation of the address between BCM and CCM the forced replication of the BCM address by using the communication Bus Test the writing of data into Micrologic by using the m m m m Magicbox RSU software communication en NIV_3_3 pdf communication Bus _ 4 Schneider LVPED508016EN 11 2008 016311A 66 Masterpact NT and NW Causes of accelerated ageing Maintenance guide Aswitchboard and
35. surement of insulation is advised every 5 Inspect for rust on metal parts years Measurement of insulation is imperative every 2 years No particular precautions required Install heating resistors in the switchboard LVPED508016EN 11 2008 Schneider 17 62605A 66 Masterpact NT and NW Maintenance guide Influence Corrosion of metal parts Causes of accelerated ageing Salt environment Appearance Appearance of m white rust on zinc coatings m red rust on steel Consequences Increase in friction Freezing of mechanism Broken springs Blocking of cores of MX XF MN control auxiliaries Risk of salt deposits on electronic circuits when thick salt mists occur Appearance of salt bridges on electronic boards Failure of electronic systems due to short circuiting of circuits particularly non varnished circuits Risk of conducting salt deposits on the device when thick salt mists occur No salt mist No influence Preventive maintenance Implement the standard program Installation No particular precautions required White deposit Moderate salt mist lt 10 km from seaside Moderate ageing of switchgear Carry out more frequent periodic checks see page 10 No particular precautions required Deterioration of device dielectric withstand resulting in risk of phase to frame short circuit and a phase to phase short circuit if an overload occurs Significant salt mist lt 1 km
36. t NT and NW Maintenance guide Corrosive atmosphere Influence Causes of accelerated ageing Corrosive atmosphere Appearance Consequences Thresholds ppm in volume Average value SO Corrosion of silver Blackening of exposed silver Increased resistance of 3C1 0 037 Sulphur dioxide aluminium and bare copper surfaces disconnecting contacts 3C2 0 11 Phenomenon accelerated by Appearance of dendrites on exposed to air 3C3 1 85 high electronic and power Excessive device 3C4 4 8 temperature and relative circuits temperature rise humidity Short circuiting of circuits resulting in non operation of the control unit H S Sulphuration of silver this Major blackening of exposed Increased resistance of 3C1 0 0071 Hydrogen sulphide phenomenon is accelerated silver surfaces disconnecting contacts 3C2 0 071 by high temperatures Appearance of dendrites on exposed to air 3C3 2 1 electronic and power Excessive device 3C4 9 9 circuits temperature rise Short circuiting of circuits resulting in non operation of the control unit Ol Corrosion of metal parts Oxidation Increase in friction 3C1 0 034 Chlorine Inter granular corrosion of Risk of mechanical rupture 3C2 0 034 stainless steel Breaking of stainless steel 3C3 0 1 springs 304 0 2 NH Attacks polycarbonates Cracking of polycarbonates Risk of rupture 3C1 0 42 Ammoniac corrodes copper Blackening of copper Increased temperature rise 3C2 1 4
37. t completely in O push the rails all the way in The right hand rail chassis alone or the circuit breaker cannot be drawn out m The crank is still in the chassis o remove the crank and store it LVPED508016EN 11 2008 Schneider 27 Electric Notes 28 Schneider LVPED508016EN 11 2008 Schneider Electric Industries SAS 35 rue Joseph Monier 92500 Rueil Malmaison France http www schneider electric com LVPED508016EN As standards specifications and designs change from time to time please ask for confirmation of the information given in this publication eS This document has been printed on ecological paper Design Schneider Electric Photos Schneider Electric Printed Ingoprint Made in Spain 11 2008 ART96031 2 2008 Schneider Electric All rights reserved
38. the switchgear age whether they are in operation or not Ageing is due primarily to the influence of the environment and the operating conditions Influence of the environment A device placed in a given environment is subjected to its effects The main environmental factors that accelerate device ageing are m temperature m percent load m relative humidity m salt environment m current harmonics m dust m corrosive atmospheres The following tables sum up for each factor m why itis harmful influence m how to identify it appearance m impact on operation consequences Ambient temperature outside the switchboard Influence Appearance Consequences Note The ambient temperature affects the device temperature which is itself affected by the percent load Major variations in temperature greater than 30 C cause both mechanical stresses thermal expansion and condensation that can accelerate ageing The mechanical characteristics of plastic parts insulation case Change in colour Breaking of parts leading to failure of are increasingly deteriorated by temperature the higher it rises functions Hardening of grease Change in colour and viscosity Device cannot be operated Elimination of grease on disconnecting contact clusters Caramel colour of clusters Increase of racking forces exerted on clusters Deterioration of insulating varnishes on coils Burning smell Failure of coils CT MN MX XF MCH
39. their control unit 40 C 85 C o devices with their control unit 25 C 85 C Devices must be stored in the open OFF position with the charging springs discharged Check and maintenance After extended storage and if the conditions above were respected the checks below must be carried out to ensure correction device operation Storage lt 2 years Run the Level II and Ill 2 year program on the subassemblies below m mechanism m control unit m device and chassis locking m chassis Storage gt 2 years Run the Level Ill and IV 5 year diagnostic program on the subassemblies below m mechanism m control auxiliaries m control unit m device and chassis locking m chassis Ifthe devices were stored under severe conditions high temperature corrosive atmosphere it is necessary to m check the surface condition of the metal parts zinc and the copper parts silver coatings Ag or tinning Sn m check the greasing for the device and chassis m clean and regrease the clusters and disconnecting contacts Schneider 11 Electric ee NT NW Level Il preventive maintenance ln recommended every year Level Il Minor preventive maintenance operations such as greasing and operating checks as well as repairs by standard exchange of certain assemblies carried outby a certified customer employee according to the manufacturer maintenance instructions Procedure number device NII_1_1 pdf Check the general c
40. tion over a long period can result in mechanical malfunctions Regular operation is required to maintain the normal performance level of each part involved in the opening and closing cycles In installations where power circuit breakers are used in source changeover systems it is advised to periodically operate the circuit breaker for the alternate source Schneider 5 Electric 056421NA 29 056455NA 37 056419NA 30 056420NA 29 Masterpact NT and NW Maintenance guide 6 Schneider Electric Masterpact NT and NW What must be maintained and why Auxiliary circuits m Control auxiliaries MX and XF shunt releases are respectively used to remotely open and close the circuit breaker using an electrical order or by a supervisor via a communication network The MN undervoltage release is used to break the power circuit if the distribution system voltage drops or fails in order to protect life emergency off or property Communicating MX and XF releases and MN releases are continuously supplied and the internal electronic components may suffer accelerated ageing if there is temperature rise in the circuit breaker Preventive maintenance consists in periodically checking operation at minimum values Depending on the operating and environment conditions it is advised to estimate their service life using the service life software and to replace them if necessary to avoid any risk of non operation when they are needed m A
41. tive humidity gt 80 Corrosive atmosphere Device installed in environment category 3C3 or 3C4 without any particular protection Salt environment Installation lt 10 kilometers from seaside and device without any particular protection Dust High level Device not protected Vibration Continuous vibrations between 0 2 and 0 5 g Example depending on the conditions m normal check on charging time 2 years m severe check on charging time 0 5x2 1 year LVPED508016EN 11 2008 Masterpact NT and NW Maintenance guide LVPED508016EN 11 2008 Recommended preventive maintenance and time intervals Device check up During the 5 year of operation it is advised to run a complete check up on the device to determine its status condition This diagnostic must be carried out by Schneider Electric Service or by certified personnel having received Level IV training The complete diagnostic must be systematically carried out following m tripping due to a short time or instantaneous short circuit m five trips due to overloads See the Level IV program voir page 14 Check after prolonged storage Storage conditions Devices must be stored in a dry ventilated room protected from rain water and chemical agents They must be well protected against dust rubble paint etc If storage is for an extended period the relative humidity in the room must be maintained below 70 m storage conditions o devices without
42. tric accessories and subassemblies m finally all the product guides available in order to maintain the device in proper operating condition The level Il and III procedures mentioned in this guide may be obtained on request from the Schneider Electric after sales support department Maintenance guide for circuit breakers and switch disconnector Masterpact NT and NW LVPED508016EN 11 2008 Contents The different types of maintenance Corrective maintenance Preventive maintenance Predictive maintenance Masterpact NT and NW What must be maintained and why The case Arc chutes Main contacts Device and chassis mechanisms Auxiliary circuits Electronic trip unit Communication module and accessories Connections Recommended preventive maintenance and time intervals Normal conditions Favourable conditions or device protected Severe conditions and device not protected Device check up Check after prolonged storage Level Il preventive maintenance recommended every year Level Ill preventive maintenance recommended every 2 years Level IV manufacturer diagnostic and replacement of components recommended every 5 years Causes of accelerated ageing Influence of the environment Ambient temperature outside the switchboard Percent load I In Relative humidity Salt environment Harmonics Dust Corrosive atmosphere Environment categories as per standard 721 3 3 Operating conditions Vibrations Number of ope
43. ts Appearance of dentrites on electronic boards operation of control unit protection measurement This phenomenon is worsened by the presence of indication and communication functions H S corrosive gas hydrogen sulphide Deterioration of electronic components in particular Not visible Failure due to short circuit or open circuit non varnished copper circuits Erosion of copper tracks Rupture of component connectors along case Oxidation of metal connectors of components and Poor contact with integrated circuit supports metal cases Oxidation of connectors of integrated circuits mounted on supports Degradation of opto electronic components Failure of data transmission lt 70 70 to 85 gt 85 Level of relative humidity generally found in Level of relative humidity generally found in zones Level of relative humidity generally found in continental and temperate zones close to water tropical zones and certain factories e g paper The level is generally lower in switchboards due Possible appearance of condensation on cold mills to the internal temperature rise No significant parts and accelerated rusting Increased risk of condensation and rust resulting deterioration is noted at this level in difficulties to disconnect devices risk of non opening or non closing Preventive maintenance Preventive maintenance Carry out more frequent periodic checks Carry out more frequent periodic checks see page 10 see page 10 Mea
44. uld be m no traces of grime grease excessive dust or condensation which all reduce insulation m no signs of burns or cracks which would reduce the mechanical solidity of the case and thus its capacity to withstand short circuits Preventive maintenance for cases consists of a visual inspection of its condition and cleaning with a dry cloth or a vacuum cleaner All cleaning products with solvents are strictly forbidden It is advised to measure the insulation every five years and following trips due to a short circuit The case must be replaced if there are signs of burns or cracks Arc chutes During a short circuit the arc chute serves to extinguish the arc and to absorb the high level of energy along the entire path of the short circuit It also contributes to arc extinction under rated current conditions An arc chute that is not in good condition may not be capable of fully clearing the short circuit and ultimately result in the destruction of the circuit breaker The arc chutes must be regularly checked The fins of the arc chutes may be blackened due to the gases produced at In but must not be significantly damaged What is more the filters must not be blocked to avoid internal overpressures It is advised to use a vacuum cleaner rather than a cloth to remove dust from the outside of the arc chutes Main contacts The contacts make and break the current under normal conditions rated current for the installation and under exceptiona
45. uxiliary wiring Auxiliary wiring is used to transmit orders to the various control devices and to transmit status condition information Incorrect connections or damaged insulation may result in either non operation of the circuit breaker or nuisance tripping Auxiliary wiring must be regularly checked and replaced as needed particularly if there are vibrations high ambient temperatures or corrosive atmospheres m Indication contacts The contacts indicating the status of the circuit breaker ON OFF of the chassis CE CD CT a trip due to an electrical fault SDE or that the circuit breaker is ready to close PF provide the operator with the status information required to react correspondingly Any incorrect indications may result in erroneous device operation that could endanger life and property Contact failure wear loose connections may result from vibrations corrosion or abnormal temperature rise and preventive maintenance must ensure that contacts correctly conduct or isolate according to their positions m Gear motor The gear motor MCH automatically recharges the operating mechanism springs as soon as the circuit breaker is closed The gear motor makes it possible to instantaneously reclose the device following an opening This function may be indispensable for safety reasons The charging lever serves simply as a backup means ifthe auxiliary voltage fails Given the mechanical forces exerted to charge the mechanism the gea
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