Electromagnetic compatibility (EMC) is the ability of electrical equipment and systems to function acceptably in their electromagnetic environment.by limiting the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI) or even physical damage in operational equipment.
The goal of EMC is the correct operation of different equipment in a common electromagnetic environment. It is also the name given to the associated branch of electrical engineering.
EMC is so important to the military that there’s a military standard MIL-STD-461 that describes how to test equipment for electromagnetic compatibility. According to IEEE, MIL-STD-461 is a set of requirements intended to serve a wide range of platforms from trucks to ships to aircraft to fixed installations, and many different applications such as above deck and below deck on a Navy ship.
Another military standard, MIL-STD-464 sets out minimal acceptable standards for the electromagnetic compatibility of ordnance and related equipment used in airborne, sea, space and ground-defense systems.
Firing circuits contained within these devices is inherently susceptible to electromagnetic environments. Testing is critical for managing the risks associated with exposure to normally occurring EMR.
Compliance with MIL-STD-464 requires demonstrating that all aspects of a system are electromagnetically compatible during each stage of their life cycle. This includes storage, transportation and maintenance as well as during normal in-service operation.
MIL-STD-464 certification is typically achievedthroughEMC/EMI testing in highly controlled, semi-anechoic chambers.
HERO (Hazard of Electromagnetic Radiation to Ordnance) testing is an essential component of achieving MIL-STD-464 compliance. HERO testing is used to determine that the ordnance safety margins required are met when the unit under test is exposed to the high levels of electric fields required by MIL-STD-464.
This requires that the test method measures the current induced into the unit’s bridgewire and compares the measurements to the pre-determined mean no-fire current (MNFC) of the bridgewire.
Want to learn more? Tonex offers Military EMI/EMC Training, a 3-day comprehensive course that covers the theory of EMC/EMI and all aspects of MIL-STD-461 and MIl-STD-464. Training also covers the basic math and the physics of EMI/EMC and the fundamentals of instrumentation, instruments, test setups and real measurements.
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