Contactors for Aerospace Grow Smarter and More Capable

Abstract

As a designer’s primary choice to control high power circuits, contactors today offer more efficient operation and smarter operation to help protect against overcurrent and faults. They are electrically controlled devices that use a low-power coil drive circuit to switch a higher power circuit. With the contactor located near the controlled load, this allows weight savings through use of smaller wiring sizes used for on/off coil control of the remote load. Contactors are a special high-power class of electrical relay designed to switch much higher currents and voltages. In a large commercial or military aircraft, contactors are used to control the different power sources, including engine-driven generators, auxiliary power units, batteries, external power, and ram air turbines. Power systems must not only accommodate the routine needs of flight, but also offer redundant backup power and emergency power.  Republished from Electronique International (June 2013)