Study the operating principles of thermal magnetic circuitbreakers. Selectivity bench

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Abel Garrett
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1 Study the operating principles of thermal magnetic circuitbreakers Selectivity bench

3 1. Presentation of the equipment 1.1 Composition The"Selectivity bench" equipment is used to study the operating principles of thermal magnetic circuit-breakers and discrimination of upstream and downstream protection devices. Its main component is a bench on castors with two working surfaces, allowing simultaneous study of overcurrent discrimination on one surface and of time discrimination on the other. The"Selectivity bench" assembly consists of: Adiscriminationbenchoncastorswithtwoworkingsurfaces,equippedandreadytouse. The bottom part of the bench houses two insulation transformers to supply the surfaces separately, a set of reactors of adjustable value for the overcurrent surface and a rheostat usedtocirculateafaultcurrentonthetimesurface.thispartalsoincludesapanelhousing the main switch, the rheostat crank handle, a load selector and a connection for external load. Asetofsafetycables. Time side Overcurrent side 3/9

4 1.2 Data Mechanicaldata: Dimensions: Height: Width: Depth(tablets folded): Depth(tablets unfolded): 1850 mm 730 mm 620 mm 1020 mm Weight:approx.150kg Electricaldata: Supplyvoltage: Frequency: Powerabsorption: Conventionalshort-circuitcurrent: Ratedsurgewithstandvoltage: Electricshockprotectionclass: Installationcategory: Measurementclass: 230V±10% 50Hz±5% 3.2kVA 10kA 2.5kV l(accordingtoie ) II l(accordingtoie ) TheelectricalnetworkmustbefittedupstreamoftheequipmentwithanRCD(Residual CurrentDevice)withasensitivityof<30mAclassAC(notsupplied). Technicaldataofthemaincomponents: Circuit-breakers C60N 16A circuit-breaker curve C C60N 6A circuit-breaker curve B, curve C C60N 4A circuit-breaker curve B, curve C C60N 20A circuit-breaker curve B, curve C, curve D C60N 10A circuit-breaker curve B, curve C, curve D Transformers 630 VA power transformer, secondary 230V 25 kva power transformer, secondary 48V 40 VA power transformer, secondary 24V RAC60rheostat,0to3000ohms 4/9

1.3 Main functions Oneofthesurfacesofthediscriminationbenchisintendedforthestudyoftime

This surface lets you understand the influence of sensitivity of the circuitbreakers and

The other surface is intended for the study of overcurrent It is equipped with five groups

5 1.3 Main functions Oneofthesurfacesofthediscriminationbenchisintendedforthestudyoftime discrimination. This surface lets you understand the influence of sensitivity of the circuitbreakers and the time delay. Various cablings are possible to mount cascading circuitbreakers. The other surface is intended for the study of overcurrent discrimination. It is equipped with five groups of circuit-breakers, a pushbutton to create a fault and indicator lights showing energised circuit-breakers. This surface lets you study the characteristics of circuit-breakers and overcurrent discrimination. Various assemblies are possible with electric flexes to form circuit-breaker associations. 5/9

6 2. Teaching 2.1 Presentation of teaching The"Protection device discrimination" teaching equipment aims at promoting understanding of the operating principles of thermal magnetic circuit-breakers and at implementing discrimination between upstream and downstream protection devices. The equipment is used to: Study the behaviour of a minimum electrical installation in the presence of a fault (overload or short-circuit) Define choice of circuit-breaker according to its tripping curve and its breaking capacity. Understand the role and advantage of associating protection devices. Itisintendedforthefollowingchannels: Professional Secondary Universities Engineering schools Electrotechnical Technicalequipment-Energy Mechanical and industrial automation Exercisesthatcanbecarriedoutonthe"protectiondevicediscrimination"equipment: they consist of a teacher's document with answers and a trainee document. Residualcurrentdiscriminationandprotectionofpeople EX1: Discovering the teaching equipment Be able to monitor device discrimination EX2: Discrimination study Be able to monitor and perform device discrimination EX3:FaultcurrentgreaterthanIn EX4:IdenticalRCDsensitivitiesandId>In EX5:FaultcurrentlessthanIn EX6: The time delay cannot be sufficient EX7:Inupstream 2xIndownstream EX8: Time delay with three levels Overcurrentdiscrimination EX 1: Plotting a tripping curve EX 2: Discrimination: theoretical application EX 3: Discrimination: discrimination with two stages EX4: Breaking: discrimination with three stages(1) EX5: Breaking: discrimination with three stages(2) EX6: Breaking by arc: viewing arc voltage 6/9

7 2.2 Teaching example 7/9

8 8/9

9 3. Elements supplied with the equipment 3.1 Equipment supplied Aprotectiondevicediscriminationbench,referenceMDG99610 Safetyflexes(length25,50and100cm)SLK425F/N 3.2 Equipment not supplied 3.3 Documentation Measurement instruments for exercises(multimeters, oscilloscopes, measurement probes, etc.). Atechnicalmanual,referenceMDG9AD611EN. Anexercisemanual,referenceMDG9AD612EN. 3.4 Contact details Schneider Electric France Activité Didactique 3F 35 rue Joseph Monier CS Rueil Malmaison - France Indigo phone No.: FR-didactic@fr.schneider-electric.com 9/9

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