Question 404Electricity & Electronics - Assistant Engineer

The correct answer is C) magnetic blowout coils. Magnetic blowout coils are used to prevent the burning of controller contacts due to arcing when opening electrical circuits. These coils create a strong magnetic field that "blows out" the arc, interrupting the current flow and preventing contact damage. This is an effective way to suppress arcing and protect the controller contacts. The other options are not the primary means of preventing contact burning due to arcing. Option A, coating the contacts with petroleum jelly, may help reduce arcing but is not the primary solution. Options B and D, overvoltage and overcurrent releases, protect against different types of faults and do not directly address the issue of arcing at the contacts.