MR254E Panel For Studying And Testing Distribution Systems (neutral point connection) Didactic Education Equipment For School Lab Electronic Trainer Kit
INTRODUCTION
This panel enables teachers to develop an exhaustive class on the state of neutral conductor in distribution systems, so that students can easily learn and test this topic. The actual electric devices assembled in the panel and proper educational terminals with high protection degree against accidental contacts enable to assemble the various confi gurations, as well as a sight check of the operation: tests can be carried out with traditional instruments.
PANEL FOR STUDYING AND TESTING DISTRIBUTION SYSTEMS (neutral point connection)
Demonstration panel with electric components, The fore panel of insulating material is the support of the necessary devices for the development of the training program. The apparatuses are indicated on the panel with standard international symbols. The application fi eld of these devices will cover installations of both civil and business and/or production (handicraft - industrial) sectors.
TRAINING PROGRAM:
This panel enables to study electric power distribution systems with reference to the following main topics:
TT, RN and IT systems
Protection against direct contacts
Protection against indirect contacts by earthing, electric separation, automatic differential switch
Protection against over-currents, selectivity in protection Devices Earthing system and conductors
Natural, artifi cial earth plates
Checking the insulation resistance in systems insulated from earth (IT)
Suitability of materials and of equipment
Protections and breaking devices
Moreover, it is possible to carry out the following instrumental measurements and checks:
Identifi cation of neutral and ground conductors
Measurement of insulation resistance
Measurement of earth resistance
Continuity tests of protection conductors
Check of the operation of differential switches
Check of the protection with automatic break
Measurement of fault loop resistance / impedance
Measurement of fi rst earth fault in insulated systems
TECHNICAL CHARACTERISTICS:
The framework is of chemically treated sheet steel, painted with several coats of epoxy paint. Its base is provided with rubber feet so that it can be positioned on any working top. The panel also includes all the necessary electrical components for a correct power supply of circuits.
The main components installed on the panel and accessible via safety terminals for plugs of Ø 4 mm, are:
1 three-phase insulation transformer of
230-400 V / 230-400 V 1500 VA
1 automatic magneto-thermal switch 4 x 6 A, C curve, with minimum-voltage releasing coil, emergency pushbutton with mechanical holding and warning light indicating panel in operation
1 power line of 230 Vac - 1 A for powering auxiliary devices
1 three-pole lever switch for inserting two different values
of earth capacitance in IT line
1 simulation of cabin earth with resistance of 0.3 Ω, 1 Ω
1 simulation of earth plate with resistances of 2 Ω, 20 Ω, 200 Ω, 2 kΩ
2 simulators of electric uses with sinusoidal or one-way earth fault current, fault resistance of 50 kΩ, 15 kΩ, 5 kΩ, 1.5 kΩ, 500 Ω, no-resistance earth fault
1 monitor for insulation control in IT systems with regulation
of the value of intervention sensitivity and scale for monitoring the instantaneous value of system insulation resistance
1 automatic differential magneto-thermal switch 4 x 2 A, C curve, class AC, possibility of using only the magnetothermal switch without the differential section
1 four-pole differential circuit breaker of 25 A / 0.3 A, class A, “S” selective
1 set of three fuse holders, with breakable neutral conductor
and fuses 10.2 x 38 of 1 A and 2 A 1 automatic magnetothermal differential switch 2 x 1 A, curve C, class AC, with possibility of using the only magnetothermal switch without the differential part
1 automatic magnetothermal differential switch 2 x 1 A, curve C, class A, with possibility of using the only magnetothermal switch without the differential part
1 differential relay coupled to a toroidal transformer with adjustable current Idn and intervention time
Dimensions of panel: 800 x 600 mm
Dimensions of framework: 840 x 450 x 680 mm
Net weight: 45 kg
REQUIRED
UTILITIES (PROVIDED BY THE CUSTOMER)
Power supply: 400 Vac 50 Hz three-phase - 1500 VA
(Other voltage and frequency on request)
OPERATIONAL HANDBOOK
WITH EXERCISES
ACCESSORIES:
Three-phase power cord of 5 m with EEC socket and plug
20 jumpers with safety plugs of Ø 4 mm for assembling various installation conditions
Set of 20 various leads with safety plugs of Ø 4 mm 
