It allows students to adjust the fault current in four different protection circuits totest and compare them. A variable transformer inside the unit works with theload to set and control the fault current in each of four circuits. This equipment works with a suitable three-phase supply andload to show how the most common circuit protection devices perform. To show students how industrial switching circuits work, eachcircuit includes a contact breaker, switched by an industrial standarddiscrepancy switch. Circuit one includes an additional adjustable residualcurrent detector for experiments with different residual current faults. Each circuit has a different current protection device, including fuses, a magneticonly circuit-breaker, a thermal only circuit-breaker, and a thermo magneticcircuit breaker. This uses lamps to show the students when each of the fuses breaks. It shows the fault current and breaking time relationship for differentfuse types. It includes a digital display and switches to help set the earth leakage faultcurrent before the test. Circuit two tests fuses and includes a fuse break detector circuit.
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