MIL-461 Standard CE101 Conducted Emissions Testing
As a leader in EMC regulatory compliance testing, Keystone Compliance assists electronic equipment manufacturers with MIL-STD 461 EMC testing. Meeting the IEC, EN, and other MIL-STD-461 testing requirements can be challenging. Not only do we understand the challenges, but we help guide companies through the process.
Keystone takes pride in providing the peace of mind that all of your CE and MIL-STD-461 testing needs will be met. Keystone Compliance’s accurate test reports are delivered quickly using our “four-eyes” approach. Meaning that multiple engineers and technicians review each report, ensuring that all the information required is present. Our MIL-STD-461 test engineers work with clients to quickly develop appropriate and concise test plans. We have a reputation of helping customers achieve their MIL-STD-461 product certifications.
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Summary of MIL-461 EMC Testing of Conducted Emissions, Audio Frequency Currents, and Power Leads
Electromagnetic compatibility (EMC) MIL-STD 461 CE101 applies to power leads from 30 Hz to 10 kHz. This includes returns that obtain power from other sources not part of the equipment under testing (EUT) for surface ships, submarines, Army aircraft and Navy aircraft.
For equipment intended to be installed on Navy aircraft, the requirement is only suitable if the platform contains Anti-Submarine Warfare (ASW) equipment. For AC applications, the requirement is applicable starting at the second harmonic of the EUT power frequency.
This MIL-STD 461 conducted emissions test procedure is used to verify electromagnetic emissions from the EUT. However, the emissions must not exceed the specified requirements for power input leads including returns.
The requirements of the MIL-STD-461g standard are applicable to EMC devices from 30 Hz to 10 kHz. There is no provision on output leads from power sources. Since power quality standards are normally used, there is no need for separate EMI requirements on output leads.
Scope of EMC MIL-STD 461 Compliance Device Testing
The limits for this military standard test are in terms of current. This is due to the difficulty in controlling the power source impedance in test facilities at lower frequencies. Emission current levels are somewhat independent of power source impedance variations. This is concluded as long as the impedance of the emission source is large relative to the power source impedance.
For surface ships and submarines, this EMC MIL-461 test helps control the effects of conducted emissions peculiar to the shipboard distribution system. Harmonic line currents are limited for each electrical load connected to the power distribution. Although a ship’s primary power is ungrounded, there exists a virtual AC ground at each electrical load due to capacitance to chassis.
For army aircrafts, the conducted emissions EMC 461-test ensures that the EUT does not corrupt the power quality on the power buses. The Army aircraft limits are based on relating the allowable current into a 1.0 ohm impedance. The Army limit includes a 20 dB margin to allow for contributions from multiple emission sources.
Lastly, for Navy aircrafts, the requirement is applicable for installations using Anti-Submarine Warfare (ASW) equipment. Specifically equipment in the same cabinet or avionics bay, or that share the same power bus as the ASW cables. In addition, the requirement is tailored for equipment that uses more than 6 amps of current on-board an ASW aircraft.
Data is presented from the EMC and conducted emissions military testing lab as follows:
- Continuously and automatically plot amplitude versus frequency profiles on X-Y axis outputs. Manually gathered data is not acceptable.
- Display of the applicable limits on each plot.
- Minimum frequency resolution of 1% or twice the measurement receiver bandwidth. Whichever is less stringent.
- The minimum amplitude resolution of 1 dB for each plot.
- Plots are provided for both the measurement and system check portions of the procedure.
MIL-461 Standard Electromagnetic Compatibility (EMC) Test Procedures
First, the measurement equipment is first turned on to allow for sufficient stabilization time. Next, a measurement system integrity check is performed. This evaluates the overall measurement system from the current probe to the data output device.
Lastly, EUT testing. The conducted emissions from the EUT is determined from the input power leads. This is done by turning on the EUT and allowing time for stabilization. Conducted emissions are also determined by selecting an appropriate lead and clamp, and scanning the measurement receiver.
Keystone Compliance Provides Expert EMC Compliance Services
Keystone Compliance can accommodate fixed, mobile and portable devices of all sizes. In addition to EMC MIL-461 standard testing, Keystone has a full scope of expertise including environmental and package testing such as vibration, accelerated aging, and ingress protection. Our team strives to give our customers more time and energy on product development instead of testing.