32 Amps Three-Phase LISN for MIL-STD-461 CE102 Testing

General

• Product Type: Three-Phase LISN
• Application: CE102 Conducted Emissions Testing
• Standards: MIL-STD-461D/E/F/G
• Network Type: 50 Ω / 50 µH Four-Conductor
• Frequency Range: 10 kHz–10 MHz

Insertion Loss

• 10 kHz–150 kHz: <26 to <21 dB
• 150 kHz–10 MHz: <21 dB

Input Power Ratings (EUT)

• Maximum Current: 32 A per phase (continuous)
• AC Voltage: 865 V rms (L-L), 500 V rms (L-G); 50/60 Hz
• AC Voltage: 270 V rms (L-G) at 400 Hz; 135 V rms (L-G) at 800 Hz
• DC Voltage: 600 V DC

Connections

• 50A receptacle pins / plug sockets / receptacle sockets / plug pins
• RF Port: 50 Ω N-Type (female)
• Fiber Optic Ports: Avago Duplex Latching POF
• Remote Power Input: 6 VDC, 500 mA
• Fan Power Input: 15 VDC, 500 mA

Environmental / Cooling

• Cooling: Louvered panels with dual forced-air internal fans

Product Weight

• Weight: 51.70 lbs (23.45 kg)

LI-3P-432 V2.0 MIL-STD-461 Three-Phase LISN FAQs

What is the LI-3P-432 and which CE102 measurement requirement does it fulfill?

The LI-3P-432 V2.0 is a four-conductor, 50Ω, 50 μH three-phase Line Impedance Stabilization Network (LISN) designed for CE102 power-line conducted emissions compliance testing per MIL-STD-461D, E, F, and G at 32 amperes per phase. It provides a stable 50Ω impedance reference across 10 kHz to 10 MHz, isolates the EUT from the facility power source, and couples disturbance voltages to the coaxial measurement port. Its 32 A rating addresses medium-power three-phase military equipment beyond the 16 A LI-3P-416's capability.

What MIL-STD-461 revisions does the LI-3P-432 comply with and why does this matter for DoD programs?

The LI-3P-432 complies with MIL-STD-461D, E, F, and G. Compliance across all four revisions is important because different DoD acquisition programs reference different versions of the standard. A laboratory holding a single LI-3P-432 can perform CE102 testing for programs under any of these revisions without requiring a separate LISN per specification version.

What frequency range does the LI-3P-432 cover and what makes 10 kHz to 10 MHz the correct range for CE102?

The LI-3P-432 covers 10 kHz to 10 MHz — the complete CE102 range defined by MIL-STD-461. The 10 kHz lower limit captures conducted disturbances from switching regulators and motor controllers operating at low switching frequencies. The 10 MHz upper limit covers the conducted interference range significant for military electronics. This range is narrower than CISPR 16-1-2 (which extends to 30 MHz), reflecting the specific requirements of CE102.

What military platform power supply frequencies does the LI-3P-432 support?

The LI-3P-432 supports 50/60 Hz at up to 865 V RMS line-to-line / 500 V RMS line-to-ground; 400 Hz aircraft and shipboard power at up to 270 V RMS line-to-ground; and 800 Hz high-frequency military power at up to 135 V RMS line-to-ground. The 400 Hz capability is particularly important for naval and aerospace programs where 400 Hz three-phase power is standard on military aircraft and many surface combatants.

What EUT power ratings does the LI-3P-432 support and what equipment class does this cover?

The LI-3P-432 supports 32 A per phase continuous, 865 V RMS line-to-line at 50/60 Hz, 270 V RMS line-to-ground at 400 Hz, 135 V RMS line-to-ground at 800 Hz, and 600 V DC. At 32 A on a 400 Hz 115/200 V aircraft supply this corresponds to approximately 11 kVA, covering medium-power aircraft subsystems such as three-phase motor drive assemblies, environmental control system compressors, and power distribution units.

How does the LI-3P-432 fiber optic remote switching improve efficiency and safety in a military shielded test room?

The RLI V2.0 Remote LISN Interface switches between L1, L2, L3, and Neutral from outside the shielded room via a 10-meter fiber optic cable. In a military EMC test facility, entering the shielded room between line measurements may require formal safety clearance procedures when live high-current connections are present. Fiber optic switching eliminates these interruptions and ensures the EUT stays in its steady operational state for every sweep. The galvanic isolation of the fiber link prevents control-path interference from entering the CE102 measurement path.

What insertion loss does the LI-3P-432 provide and what does this mean for the measurement sensitivity of the EMI receiver?

Insertion loss decreases from less than 26 dB at 10 kHz to less than 21 dB at 150 kHz, then remains below 21 dB from 150 kHz to 10 MHz. This insertion loss must be applied as a correction to raw receiver readings when post-processing CE102 results, to obtain the true disturbance voltage at the LISN measurement port for comparison against MIL-STD-461 limit lines.

Why is forced-air cooling included on the LI-3P-432 and how is the fan system powered?

The LI-3P-432 includes two user-controlled internal fans. Military CE102 procedures require the EUT at rated continuous load throughout the entire measurement sequence, which can span multiple hours. At 32 A, combined with 400 Hz or 800 Hz operation that increases component losses, sustained passive cooling would be insufficient. The fans are powered by a dedicated 15 VDC rear-panel supply, independent of the 6 VDC remote interface supply. Fans should be activated before energizing the EUT.

What does a complete CE102 measurement sequence look like using the LI-3P-432 in a military test lab?

The LI-3P-432 is bonded to the MIL-STD-461 bonding plane. The military power supply connects to the mains input; the EUT connects to the EUT output port using 50A rated color-coded connectors. A 50Ω N-Type coaxial cable runs to an EMI receiver configured for a 10 kHz to 10 MHz peak or quasi-peak sweep. The RLI V2.0 fiber optic cable exits through a filtered penetration. Cooling fans are activated, the EUT is energized at rated load, then the operator performs sweeps on L1, L2, L3, and Neutral sequentially, applying the insertion loss correction and comparing against the CE102 limit line.

In which military program and platform types is the LI-3P-432 most commonly required?

The LI-3P-432 is most commonly required for CE102 testing of shipboard combat system power conditioning units, aircraft environmental control system drives, military radar prime power assemblies, three-phase motor drives for naval platform machinery, armored vehicle auxiliary power unit controllers, and military communications shelter power distribution equipment. It covers defense subsystems drawing between 17 and 32 A per phase from three-phase military power systems.

Why are the LI-3P-432 connectors rated at 50A when the LISN is specified at 32 A?

The 50A connector rating provides a safety margin above 32 A, accommodating startup inrush currents, harmonic current content above the fundamental, and thermal derating in a hot test environment. Military equipment frequently exhibits high inrush on startup, and the 50A rating ensures connectors remain within their thermal and mechanical limits without impacting measurement integrity.

How does the LI-3P-432 transient limiter protect the EMI receiver during CE102 testing?

The built-in Transient Limiter incorporates low-pass and high-pass filter sections that attenuate out-of-band signals and protect the EMI receiver from instantaneous voltage transients generated during EUT switching events, load changes, or power-on surges. Military three-phase motor drives and power conditioning units can produce high-energy transients that would damage an unprotected receiver. The limiter provides this protection throughout the complete 10 kHz to 10 MHz CE102 sweep.

What grounding and bonding requirements apply to the LI-3P-432 in a MIL-STD-461 test configuration?

MIL-STD-461 requires the LISN be placed on the reference bonding plane. The unpainted mounting plate provides direct metal-to-metal contact. At 32 A, leakage currents through the chassis are substantial, and an incomplete ground bond creates both a measurement error and a personnel safety hazard. Where the plane surface is coated or contaminated, a dedicated bonding strap to a known-clean earth point must be used.

How is the LI-3P-432 calibrated and what accreditation is available?

Every LI-3P-432 is individually calibrated per MIL-STD-461. Impedance and insertion loss data across the full 10 kHz to 10 MHz range are supplied with each unit along with a certificate of calibration. ISO 17025 accredited calibration is available upon request for facilities under DoD-recognized accreditation bodies such as A2LA or NVLAP.

What are the physical dimensions and weight of the LI-3P-432?

The LI-3P-432 measures 17.36″ H × 17.79″ W × 17.48″ D and weighs 51.70 lbs (23.45 kg). The increased depth and weight over the LI-3P-416 reflect the larger air-core inductors and 50A connectors required at 32 A. Top cover exhaust outlets must remain unobstructed within the shielded enclosure for effective forced-air cooling.

How does selecting the LI-3P-432 versus the LI-3P-416 or LI-3P-463 affect a CE102 test program?

Selection within the LI-3P-4x series is based entirely on the maximum continuous current drawn by the EUT per phase. The LI-3P-416 covers up to 16 A, the LI-3P-432 covers 17 to 32 A, and the LI-3P-463 covers up to 63 A. Since all four models share the same 50Ω 50 μH topology, frequency range, and MIL-STD-461 compliance, switching between models does not affect CE102 methodology or applicable limit lines. Select the lowest-rated model that comfortably accommodates the EUT's rated current including startup inrush.

How is the LI-3P-432 used when testing a 400 Hz aircraft environmental control system drive under MIL-STD-461?

Aircraft environmental control system (ECS) compressor drives are among the most common 400 Hz three-phase loads tested with the LI-3P-432. The LISN is powered at 115/200 V 400 Hz three-phase to replicate the aircraft bus. The ECS drive EUT — typically drawing 20 to 30 A per phase at rated cooling load — connects to the LISN EUT output port. CE102 sweeps from 10 kHz to 10 MHz are performed on each phase and neutral via the RLI V2.0 remote interface. Because ECS drives use variable-frequency motor control internally while drawing 400 Hz power externally, their conducted emissions include complex harmonic content across the full CE102 band that must be captured on all four lines to characterize worst-case phase imbalance.

What is a typical CE102 test scenario for military communications shelter power distribution equipment using the LI-3P-432?

Military tactical communications shelters contain racks of radio, computing, and signal processing equipment powered through a three-phase distribution panel rated at 20 to 30 A per phase at 50/60 Hz. For CE102 testing of the shelter power distribution assembly, the LI-3P-432 connects between the simulated generator supply and the shelter power input. The EUT is the entire shelter in its mission configuration with all electronics at typical operational load. CE102 sweeps on all four conductors capture aggregate conducted emissions, ensuring that when deployed and connected to a military generator, the shelter will not disrupt adjacent communications or navigation equipment through its power leads.

How is the LI-3P-432 applied in a naval prime contractor's pre-delivery EMC qualification of a shipboard power conditioning unit?

Before a shipboard power conditioning unit (PCU) rated at 25 A per phase on a 60 Hz 440 V three-phase ship service bus can be delivered to the Navy, it must pass MIL-STD-461 CE102 qualification. The LI-3P-432 is powered from a regulated 440 V 60 Hz three-phase supply, and the PCU connects at rated load. CE102 sweeps cover 10 kHz to 10 MHz on all four conductors at steady-state and at a load step transition to capture transient-induced emissions. The resulting data, with LI-3P-432 insertion loss correction applied, is submitted as part of the MIL-STD-461 test report that forms the basis for the Navy's formal acceptance of the equipment.

How do defense prime contractors use the LI-3P-432 during development testing to reduce CE102 qualification risk?

Defense prime contractors frequently install an LI-3P-432 in their engineering development laboratory for ongoing CE102 pre-compliance monitoring during the hardware design phase. As firmware updates, PCB revisions, and filter changes are implemented, engineers run periodic CE102 spot checks with the LISN and a spectrum analyzer to confirm design changes do not push emissions toward the MIL-STD-461 limit. This approach catches CE102 issues at the development bench — where they cost relatively little to fix — rather than at the formal qualification test event where failures cause significant schedule delays and contract penalties. The same LI-3P-432 model used for development pre-compliance is also used at formal qualification, ensuring continuity of measurement conditions.

What are the CE102 test challenges specific to military radar power supply units, and how does the LI-3P-432 address them?

Military radar power supply units contain high-voltage pulse modulators and magnetron or TWT power converters that generate broadband conducted emissions across the full 10 kHz to 10 MHz CE102 band. These units typically draw 20 to 30 A per phase from the three-phase supply during peak power transmission. The LI-3P-432 handles this current range with appropriate margin and provides the stable 50Ω 50 μH impedance reference required for reproducible CE102 measurements on highly dynamic loads. The built-in transient limiter is particularly valuable during radar power supply testing because high-voltage switching events generate energy spikes on power leads that would otherwise damage an unprotected EMI receiver.

How is the LI-3P-432 used at a defense prime contractor’s system integration laboratory when qualifying a 400 Hz shipboard power conditioning unit?

A shipboard PCU drawing 25 A per phase from a 400 Hz three-phase supply is pre-qualified with the LI-3P-432 before formal government acceptance testing. The LI-3P-432 connects between a regulated 400 Hz supply and the PCU input at rated output power, and CE102 sweeps from 10 kHz to 10 MHz reveal the conducted emission profile. Any emissions approaching the CE102 limit can be addressed before the formal government acceptance test, where a failure would trigger a contractual non-conformance report and a mandatory corrective action process.

What is a typical scenario where the LI-3P-432 is used at a military aircraft prime contractor to test a 400 Hz multi-function power distribution unit?

A fighter aircraft multi-function PDU drawing approximately 28 A per phase from the 400 Hz aircraft bus at peak load is tested with the LI-3P-432 under MIL-STD-461G with all downstream avionics loads active. CE102 sweeps from 10 kHz to 10 MHz are performed at both steady-state and during load step transitions to capture transient-induced conducted emissions. The RLI V2.0 remote switching allows the test to proceed continuously under strict electromagnetic quiet conditions without personnel entry into the shielded facility.

How is the LI-3P-432 used at a government-recognized EMC test facility performing CE102 verification on military ground vehicle electronic drive systems?

Military ground vehicle APU controllers and battery charging systems drawing 20 to 32 A per phase from the vehicle’s three-phase generator are tested through their full range of operating modes including start-up, steady-state drive operation, and regenerative braking. The formal CE102 test report from the government-recognized facility, referencing the LI-3P-432 calibration data, becomes part of the vehicle qualification documentation submitted to the procurement authority.