Aircraft switch and relay inductive circuit testing

THE MAJOR FACTOR determining the life of current-carrying contact systems is contact metal erosion resulting from electric discharge in the contact gap. In general, contact system deterioration is proportional to the energy dissipated in the contact gap. Typically, a 5-ampere aircraft fire extinguisher solenoid may discharge 2.69 joules of energy in the contact gap compared to an 0.2 joules of energy in the contact gap for a 5-ampere resistive circuit.