EMI / EMC Requirements
Navy Shipboard & Submarines
Presented by
Jeffrey Viel, EMI/EMC Director, NTS
jeffrey.viel@nts.com
Welcome
Jeff Viel, Director of Technology, EMI / EMC
•
Mr. Viel is a degreed electrical engineer and Subject Matter Expert in
electromagnetic interference design and compatibility testing.
•
For over 20 years Mr. Viel has been providing test planning and
procedure development, project engineering/management, technical
training, product design consultation services. His primary areas of
expertise reside within the related EMI/EMC Defense, Aerospace,
Department of Energy, and Telecommunications markets.
•
As NTS Director of Technology, EMI / EMC, he is responsible for
overseeing 10 fully compliant EMI/EMC test laboratories worldwide. As
SME he provides EMI/EMC training for NTS employees, clients and
colleagues including the NYCT where he is recognized by the Practicing
Institute of Engineering Inc. (PIE) for the state of NY as an EMI course
instructor.
•
Mr. Viel is a 9 year veteran of the United States Marine Reserves and
holds a BSEE from Northeastern University. He is a member of the IEEE
and participates on many technical committees, including SC135 RTCA
DO160, and SAE International where he is a voting member of the EMC
standards committee.
2
Shipboard & Submarine
General EMI/EMC Requirements
MIL-STD-461 (Subsystem level)
• Guidance Document which provides general EMI/EMC
requirements for all electrical and electronic based equipment and
subsystems required by all branches of the DoD.
• Permits tailoring of test criteria determined on a case-by-case basis.
• Addresses Emissions and Susceptibility criteria.
–
All inclusive document including test methods, limits, and levels.
–
Also includes a detailed appendix for detailed test descriptions, and tailoring
activities.
3
Applicability Matrix
Naval Shipboard EMI / EMC Requirements
This is a general applicability list and does not address limited or specified type tests.
MIL-STD-461F
Description
Applicability
CE101
Conducted Emissions, Current 30 Hz to 10 kHz
Input Power Lines
CE102
Conducted Emissions, Voltage 10 kHz to 10 MHz
Input Power Lines
CS101
Conducted Susceptibility, Voltage 30 Hz to 150 kHz
Input Power Lines
CS106
Conducted Susceptibility, Transients
Input Power Lines
CS109 (Subs only)
Conducted Susceptibility, Structure Current 60 Hz to 100 kHz
Enclosure
CS114
Conducted Susceptibility, BCI 4 kHz to 200 MHz
All interconnecting cables
CS116
Conducted Susceptibility, Damped Sinusoidal Transients
10 kHz to 100 MHz
All interconnecting cables
RE101
Radiated Emissions, Magnetic Field 30 Hz to 100 kHz
Enclosure
RE102
Radiated Emissions, Electric Field, 10 kHz to 18 GHz
Enclosure
RS101
Radiated Susceptibility, Magnetic Field 30 Hz to 100 kHz
Enclosure
RS103
Radiated Susceptibility, Electric Field 2 MHz to 18 GHz
Enclosure
4
EMI / EMC Test Requirements
An approved Electromagnetic Interference Test Plan (EMITP) is
required prior to conducting formal testing per DI-EMCS-80201C .
• Detailed step by step procedures of each applicable test
method.
• Limits (emissions tests), Levels (susceptibility tests).
• Justification for any tailored activities, exceptions, or exclusions.
• Detailed description of the equipment being tested
• Purpose and intended function of the equipment under test (EUT).
• Parametrics (size, weight, power requirements, etc…)
• Configuration (number of cables, types of cables, length of cables
expected in the installation, grounding configuration, & operational
parameters.
EMI / EMC Test Requirements
• EUT cabling must be representative of the
actual installation!
• Equipment cabling plays a major roll in
EMI/EMC compliance to MIL-STD-461. The
type of cable used may impact both emissions
and susceptibility test results.
• Twisted or untwisted unshielded pairs
• Shielded or unshielded cabling
• Cable shields grounded at one or both ends.
6
EUT Cable Lengths are Specified
Input Power Cables
Defined as any input lead that obtains power from a shared utility source (not
part of the EUT).
• 2 meters routed to front edge of set up from EUT to the LISN termination. Shall not
exceed 2.5 meters in total length.
Interconnecting Leads and Cables
Defined as any electrically conductive lead or cable that interfaces with the EUT
(communication, alarm, or power).
• Shall be the actual installation
length. If greater than 10 meters,
at least 10 meters will be required.
• If actual length is unknown or
un-specified, then at least
2 meters shall
be provided.
7
EUT Installation Requirements
Equipment Cable Routing
• All electrical cabling is elevated above the ground plane by 5 cm to minimize
capacitive coupling effects.
• Cables are routed to the front edge of the test setup for 2 meters and
separated by 2 cm.
• The cable closest to the front edge shall be spaced 10 cm from the front edge
of the ground plane.
8
EUT Installation Requirements:
Orientation & Loading
• EUTs shall be oriented such that surfaces which produce maximum
radiated emissions and/or respond most readily to radiated signals
face the measurement antennas. (door seams, large apertures,
ventilation ducts, connector panels, video displays, etc…)
• All EUT electrical interfaces shall be terminated with either the actual
equipment from the platform installation or representative loads
which simulate the electrical properties.
• Generally, the maximum
load is selected to represent
the installation environment
(within reason).
• Equipment orientation and loading
are generally determined by
analysis or test.
9
EUT Installation Requirements:
Bonding and Grounding
• Only the provisions included in the design of the EUT shall be used
to bond units such as equipment case and mounting bases together,
or to the ground plane.
• When bonding straps are required, they
shall be identical to those specified in
the installation drawings.
• Shock or vibration isolators shall be used
if required in the installation.
• The bonding straps shall only be used
when furnished with the mounting base.
Grounding strap
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EMI/EMC Test Requirements
•
Precautions are commonly taken to ensure electrical support/monitoring and loading circuits do not
interfere with emissions measurements, or become susceptible when interface cabling is subjected
to EM exposure tests.
•
Cables shield terminations at the feed-through port, or EMI filtering of unshielded lines are
commonly required. However, potential effects of these precautions must be considered.
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CE101 Conducted Emissions Current Test Method
• Applicable to AC or DC input power
leads that obtain power from sources
not considered part of the EUT.
• Current measurement (dBµA) made
between 30 Hz – 10 kHz.
• Pass fail criteria based upon set (not
to exceed) limits.
• Limits are based on the current
waveform measurement criteria
specified in MIL-STD-1399 section
300A.
12
CE101 Conducted Emissions Current Test Method
•
60 Hz power limits for Surface
Ships & Submarines are based on
power demand (i.e., < 1kVA, or ≥
1kVA).
•
The basic < 1kVA limit is based on
a fundamental current draw of 1
amp 120 dBµA decaying to 76
dBµA at 10 kHz (20 dB/decade
slope rate).
•
The limit is relaxed/extrapolated
where EUT fundamental currents
exceed 1 amp, but less than 1 kVA
Limit Relaxation: 20*log (rms current)
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CE101 Conducted Emissions Current Test Method
• The basic ≥ 1kVA limit is also based an a 1 amp current draw.
• Limiting harmonic currents to 3% of fundamental current draw of 1 amp from
the 2nd harmonic to the 32nd harmonic, then decaying at a rate of 20 dB/decade
to 10 kHz.
• Limit is also relaxed
using 20*log( current)
over 1 amp.
14
CE101 Conducted Emissions Current Test Method
• Submarines also have a CE101 limit for DC power applications.
15
CE101 Design Considerations
•
Odd Harmonic orders currents can be problematic for power conversion
technologies used in power supplies, VFD’s and motor controllers.
•
Internal filtering is
designed assuming
maximum load currents
which becomes less
effective at lower current
draws.
• Additional filtering is commonly needed for high current systems operating a
loads < 60% of full rated capacity. Conventional low pass EMI filters are
ineffective in suppressing harmonic currents due to their low frequency cut off.
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CE102 Conducted Emissions Voltage Test Method
• Voltage measurement (dBµV) 10 kHz to 10 MHz.
• Applicable to AC or DC power leads that obtain power from sources not part of
the EUT.
• Measurement made off of each 50 µH Line impedance stabilization Network
(LISN).
•
•
Derived from the ANSI C63.4 low frequency & high frequency circuits.
Impedance value can be tailored to best match the product and installation.
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CE102 Conducted Emissions Voltage Test Method
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CE102 Conducted Emissions Voltage Test Method
• One basic curve is used for all applications (based on 28 Volts), then relaxed
based upon the specific operating voltage.
• The 28 V curve is place 20 dB lower than the MIL-STD-704 Power quality curve
to minimize additive noise contributions from platform equipment, and to account
for platform bus impedance variances.
• The relaxation for
other voltages is
based on the relative
control levels for
ripple voltage.
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CE102 Design Considerations
• EMI power line filters are commonly required to comply with CE102.
• Be aware of the EMI filter selected, not all are created equally!
• MIL-STD-461 starts at 10 kHz
• FCC/CE Mark starts at 150 kHz
• MIL-STD filters are generally larger/heavier, and more
expensive.
• Be aware of the Navy shipboard requirement for
common mode capacitance!
• 0.1 µF for 60 Hz
• 0.02 µF for 400 Hz
• 0.03 µF for DC loads
< 500W on Submarines
• 0.075 µF/kW of connected
load >500W on submarines
• Do not assume a device that meets FCC or CE Mark Criteria will comply
with MIL-STD-461.
• MIL-STD-461 requires peak data (worst case)
• FCC/CE Mark requires quasi-peak , and average data. (modulated noise contribution).
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RE101 Radiated Magnetic Field Emissions Test Method
• Note that the limit does not take
into account magnetic effects
from equipment such as magnetic
launchers, magnetic guns and
the like.
Amplitude (dBpT)
• Near field radiated Magnetic field emissions test performed from 30 Hz to
100 kHz.
• Intended to limit the low frequency magnetic field emissions from equipment due
to the close proximity of electronic and electrical systems and associated cables
installed on the Navy platforms, and the sensitivity of low frequency sensors and
systems. (low frequency acoustic systems, ELF, VLF/LF communications
systems and sensors that have sensitivities in the nV range).
21
RE101 Radiated Magnetic Field Emissions Test Method
•
Magnetic field measurements made with a electrostatically shielded
loop antenna (13.3cm diameter).
•
Measurements made 7 cm from all faces of the EUT, and connectors
to locate and maximize the magnetic field level.
• Minimum of 2 frequencies per octave below 200 Hz
• Minimum of 3 frequencies per octave above 200 Hz
•
If the specified emissions limits are
exceeded, the measurement distance
is increased until the emissions fall within
the limit.
• EUT Still needs to meet the criteria
at 7 cm distance.
22
RE101 Design Considerations
• Position high magnetic field emitters as far away from enclosure
walls.
• Try to minimize loop lengths, loop diameters.
• Magnetic field intensity is proportionate to the distance from
the source.
• Use steel versus aluminum cabinets or enclosures to minimize
magnetic field readings.
• Use small patches of ferrous material to redirect and dissipate
field currents.
• Ferrous materials like steel, or Mu metals possess high
absorptive properties which can be used to reduce magnetic
emissions
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RE102 Radiated Electric Field Emissions Test Method
• Measures the electric field emissions radiated from equipment enclosures and
cables from 10 kHz – 18 GHz.
•
•
Testing is required up to 1 GHz or 10x highest clock to 18 GHz.
RE102 Testing not required above 18GHz.
• Measurement are made with linearly
polarized antennas.
•
•
•
Vertically polarized fields measured
<30MHz (using rod antennas)
Horizontally and vertically polarized fields
measured >30MHz.
Specific Antenna types:
10kHz – 30 MHz 104 cm (41 in) rod,
with impedance matching balun.
30 MHz – 200 MHz Biconical (137 cm) tip to tip
200 MHz – 1GHz Double ridge horn 69 cm by 64.5 cm opening
1 GHz – 18 GHz Double ridge horn 24.2 cm by 13.6 cm opening
• Log spiral antennas, and Log periodic antennas are not permitted.
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RE102 Radiated Electric Field Emissions Test Method
• All measurements are made from a distance of 1
meter.
• Number of antenna positions are to be determined.
• Below 200 MHz- the test boundary is divided
by 3 and rounded up to nearest integer.
• Between 200 – 1000 MHz entire width of EUT,
plus first 35 cm of cables must be within 3 dB
beamwidth.
• Above 1 GHz entire width of EUT, plus first 7
cm of cables must be within 3 dB beamwidth.
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RE102 Design Considerations
• A device that has met FCC or CISPR radiated emissions requirements may not meet RE102.
•
MIL-STD-461 requires peak measurements made at 1 meter, FCC and CISPR requires
quasi peak and average measurements made from either 3 or 10 meters.
•
Differences in test methodologies make comparing results difficult.
• Cables contributors to radiated emissions not just equipment enclosures.
• 2 meters of cabling is intended to maximize radiated coupling from 10 kHz – 18 GHz.
– < 150 MHz noise problems are generally related to cable issues.
– > 150 MHz noise problems are generally related to enclosure issues.
• Shielded cables and/or integrated EMI filtering are common solutions.
• Good electrical Bonding and grounding schemes will help reduce most RE102 issues.
Per MIL-STD-464C:
• 10 milliohms or less from the equipment enclosure to system structure, including the
cumulative effect of all faying surface interfaces.
• 15 milliohms or less from cable shields to the equipment enclosure, including the cumulative
effect of all connector and accessory interfaces.
• 2.5 milliohms or less across individual faying interfaces within the equipment, such as
between subassemblies or sections.
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RS101 Radiated Magnetic Field Susceptibility Test Method
• Ensures equipment performance does not degraded when exposed to magnetic
fields radiated from 30 Hz to100 kHz.
– Applicable to all Navy Shipboard equipment.
– For submarines, only applicable to equipment operating at 100 kHz or less and with
an operating sensitivity of 1 μV or less.
• The Navy limit was established by measurement of magnetic field radiation from
power distribution components (transformers and cables), and the magnetic field
environment of Navy platforms.
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RS101 Radiated Magnetic Field Susceptibility Test Method
• A 12 cm transmit loop consisting of 20 loops of 12 AWG. Wire.
• The loop is oriented in the parallel axis 5 cm from EUT.
• It is Positioned every 30 cm x 30 cm (1 foot ²) area over each face
including each connector interface.
• Initially field levels 10 dB greater than specified are produced (not to
exceed 15 amps) to quickly
detect potential susceptibility
issues.
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RS101 Design Considerations
• Similar to the RE101 design considerations.
• Position sensitive magnetic field receivers away from enclosure walls.
• Try to minimize loop lengths, loop diameters.
• Magnetic field intensity is proportionate to the distance from the source.
• Use steel versus aluminum cabinets or enclosures to minimize
magnetic field readings.
• Use small patches of ferrous material to redirect and dissipate field
currents.
• Ferrous materials like steel, or Mu metals possess high absorptive
properties which can be used to reduce magnetic emissions
29
RS103 Radiated Susceptibility Electric Field Test Method
•
RS103 ensures that equipment will operate without degradation in the presence of
electromagnetic fields present at the installation platform.
•
RS103 is required to 18 GHz, but may be extended to 40GHz by the procuring agency.
• Driven by the platform EME, & Risk of exposure to intentional radiators (above decks, located
external to ships or subs hull).
•
RS103 levels are simply based on levels expected to be encountered during the service
life of the equipment.
–
–
–
–
Ships internal, Below Decks- Metallic Hull – 10 V/M
Ships internal, Below Decks- Non-Metallic Hull – 50 V/M <30 MHz, 10 V/m >30MHz
Submarines Internal – 5 V/m <30 MHz, 10 V/M >30 MHz
Ships & Submarines External – 200 V/m
Note * Equipment located external to the pressure hull of a submarine but within the superstructure, use the Ships
(metallic) below decks limit (10 V/m)
•
These test level do not necessarily represent the worst-case environment to which the
equipment may be exposed. RF environments can be highly variable, particularly for
emitters not located on the platform.
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RS103 Radiated Susceptibility Electric Field Test Method
• Antenna positioning similar to RE102 methods.
• Transmit antenna set at a distance of 1 meter for
EUT & cabling.
• Number of antenna positions are to be
determined.
– Below 200 MHz- the test boundary is divided by 3
–
–
and rounded up to nearest integer.
Between 200 – 1000 MHz entire width of EUT,
plus first 35 cm of cables must be within 3 dB
beamwidth.
Above 1 GHz entire width of EUT, plus first 7 cm
of cables must be within 3 dB beamwidth.
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RS103 Radiated Susceptibility Electric Field Test Method
• The frequency range can be swept or stepped
– Each discrete stepped frequency shall
be dwelled for a time based on the
equipment operating cycle, but for no
less than are 3 seconds .
• The step size above 1 GHz has been
relaxed to expedite testing . However
critical frequencies that would not be covered must be specifically included in
the RS103 test range.
Susceptibility Thresholding
• Susceptibility and operational anomalies are not acceptable.
• When EUT susceptibility is detected, a threshold level shall be determined
where the susceptible condition is no longer present.
•
•
•
reduce the interference signal until the EUT recovers.
Reduce the interference signal by an additional 6 dB.
Gradually increase the interference signal until the susceptibility condition reoccurs.
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RS103 Radiated Design Considerations
• RS103 Design considerations are similar to those described for RE102.
• Radiated susceptibility can be caused by cabling as well as equipment enclosures.
•
2 meters of cabling is intended to maximize radiated coupling from 10 kHz – 18 GHz.
– Susceptibility issues < 150 MHz are generally related to cable issues.
– Susceptibility issues > 150 MHz are generally related to enclosure issues.
• Shielded cables and/or integrated EMI filtering are common solutions.
• Seems, slots, and apertures are points of entry and potential causes for
susceptibility.
•
•
360 degree cable shield terminations, filtered connector assemblies, or PCB mount filtering will
improve cable induced susceptibility issues.
The use of EMI compression gaskets around doors, and panels will improve enclosure induced
susceptibility issues.
• Low transfer impedance and high shielding effectiveness of cables and enclosures
will reduce internal noise from getting out, and external noise from getting in.
•
•
IEEE 299 describes test methods for evaluating shielding effectiveness of enclosures
Test standards, IEC 61196-1 , IEC 62153-4-6 describe methods for evaluating transfer
impedance and shielding effectiveness for shielded coaxial cables.
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CS101 Conducted Susceptibility Voltage Test Method
•
Injects a swept AC signal onto EUT input power leads (high sides only) .
•
•
Test Levels are based on input voltage level
•
•
Intended to ensure that equipment performance is not degraded from differential mode
ripple voltages associated with allowable distortion of shared utility sources.
•
no requirement to test output power leads.
Either Curve#1 > 28V, or Curve#2 ≤28V
• 30 Hz – 150 kHz ( DC power leads)
• 2nd harmonic – 150 kHz (AC leads)
CS101 limits are based on the spectral
content requirements of MIL-STD-704.
• Curve#1 is approximately 6 dB above
typical power quality limits, although
the limit has been somewhat
generalized to avoid complex curves.
•
The difference between the limits for
CE102 and CS101 of approximately
26 dB should not be viewed as a margin.
• The CE102 limit is placed so that ripple voltages do not exceed that allowed by the power
quality standards due to interference contributions from multiple EUTs.
34
CS101 Conducted Susceptibility Voltage Test Method
•
The test voltage is coupled to the input power through a coupling transformer.
•
The signal generation equipment must be capable of achieving the voltage into a .5 ohm
load (80 Watts), while maintaining a sinusoidal waveform.
•
Test can also be performed on 3 phase systems (one phase tested at a time).
•
Performed on system current draws up to 100 amps.
•
Voltage Threshold verification is performed where susceptibility is detected.
35
CS106 Conducted Susceptibility Transient Test Method
• A test which simulates voltage transients experienced on
shipboard power systems coupling to interface wiring
inside enclosures.
• Typically caused by switching of inductive loads, circuit
breaker (or relay) bounce, and load feedback onto the
power distribution system.
• Applicable to submarine and surface ship equipment and
subsystem AC and DC input power leads, not including
grounds and neutrals.
36
CS106 Conducted Transient Test Method
• The 400 volt peak, 5 microsecond pulse represents the typical transient
observed on 115V and 440V power distribution systems.
• Measurements of transients on
Navy platforms have shown the
transient durations (widths) are
predominantly in the 1 – 10
microsecond range.
• The large majority (> 90%) of the
transients measured on both the
115 volt and 440 volt ac power
distribution systems were between
50 and 500 volts peak.
37
CS106 Conducted Transient Test Method
CS106 Single phase test setup
38
CS109 Structure Current
• Applicable to equipment and
subsystems that have an operating
frequency of 100 kHz or less and an
operating sensitivity of 1 μV or better
(such as 0.5 μV).
• Handheld equipment is exempt from
this requirement.
• This test procedure is used to verify
the ability of the EUT to withstand
structure currents up to 1 amp.
39
CS109 Structure Current
Test Configuration
•
•
•
AC sources are isolated
Safety grounds are disconnected
A single point ground condition is established.
Equipment that will not be rack mounted:
At diagonal extremes across only the mounting
surface.
Rack mounted equipment:
At diagonal extremes across all surfaces of the
equipment.
Deck resting equipment:
At diagonal extremes across all surfaces of the
equipment.
Bulkhead mounted equipment:
At diagonal extremes across rear surface of
the equipment.
Cables (all mounting methods): Between cable
armor, which is terminated at the EUT, and the single
point ground established for the test setup.
40
CS114 Conducted Susceptibility BCI Test Method
• Simulates currents that will be developed on platform cabling from
EMI fields generated by antenna transmissions (RS103) both on and
off the platform.
• CS114 provides data that can be directly related to induced current
levels measured during platform-level evaluations.
• CS114 is performed on all power & signal cables.
• Additionally, EUT’s intended to be installed on ships or submarines,
testing from 4 kHz to 1 MHz shall be performed on complete power
cables (common mode test).
41
CS114 Conducted Susceptibility BCI Test Method
CS114 Test Levels for Navy Ships
All Ships &
Subs (common
mode)
Metallic Ships
Below decks
Metallic Ships
Above decks
42
CS114 Conducted Susceptibility BCI Test Method
CS114 Calibration
CS114 Test
43
CS116 Conducted Susceptibility Sinusoidal Transient Test Method
• Simulates damped sinusoidal transients occurring in platforms from
excitation of natural cable resonances.
• Caused by both external stimuli (lightning and electromagnetic pulse)
and from platform electrical switching phenomena.
• Broad frequency coverage (10 kHz – 100 MHz) to account for a wide
range of conditions.
Applicable to all interconnecting cables (I/O, power cables), including
individual high side power leads.
•
Power returns and neutrals need not be
tested individually.
44
CS116 Conducted Susceptibility Sinusoidal Transient Test Method
• Performed at 10 kHz, 100 kHz, 1 MHz,
10 MHz, 30 MHz, and 100 MHz.
• Additional specific resonance
frequencies can be selected if known.
• Transients between1 MHz and 30 MHz
Can reach up to 10 Amps peak
•
Required for all procurements (Air Force
used to be 5 amps)
• Applied at a 1-2 pps rate for 5 minutes per
cable.
• Performed during for each mode of
operation.
•
“Powered Off” testing requirement was removed.
45
CS116 Conducted Susceptibility Sinusoidal Transient Test Method
• Pulses are inductive coupled to each line.
• Induced Currents are monitored during the
test.
•
Method similar to CS114 and CS115.
• A threshold analysis is required at each
frequency where susceptibility is observed.
46
Conducted Susceptibility Design Considerations
• Robust cable shielding and proper ground terminations
are common design implementations for MIL-STD 461
compliance.
• Low impedance terminations (transfer impedance < 15 milliohms).
• High Shielding Effectiveness (SE = > 60 dB).
• Installing low pass EMI filters and properly rated surge
protection devices on power lines and unshielded lines
is highly recommended.
• EMI Filters should be designed to provide between 40 and 60 dB
of insertion loss at 10 kHz. However, some product designs will
allow 20 dB.
• Be cognizant of the Navy common mode capacitance limitations
for power entry filtering. Inductive filters are commonly used.
• Metal Oxide Varistors, and/or zenor diode type transient
suppressors
47
Thank You
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