3U ATR with 5 Heat Exchangers and Multi Slot Heat Pipes

Rugged SEALED Heat Pipe COTS 3U ATR. Available in 3, 5, 7 & 9 slot versions, supporting up to 750 watts payload. Certified per MIL-461G & MIL-810H for immediate deployment.
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3U ATR with 5 Heat Exchangers and Multi Slot Heat Pipes

Custom COTS - Customer configurable & loaded with options: Extended bottom & top covers, front panel connectors, logos & silk screening, etc.
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3U VPX military Gen 4/5 Backplanes

Custom COTS - Customer configurable & loaded with options: Extended bottom & top covers, front panel connectors, logos & silk screening, etc.
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3U ATR PENTAHEX-HP Description

Sealed, 1" pitch, high performance dry-air 3U chassis incorporates five heat exchangers, multi slot heat pipes and air re-circulation fans inside. This conventional format chassis is ideal for applications where ambient air is laden with hostile or harmful contaminants.


Heat generated within the enclosure is conducted to the hollow sidewalls, bottom cover, top cover & rear panel heat exchanger where it is dissipated to the ambient environment by forced air rear fans or by vehicle platform air plenum. Integrated card-cage slot heat pipes provide fast passage for heat to exit the internal card-cage. Internal air recirculation fans ensure constant airflow across modules.


The 3U PENTAHEX-HP chassis is available in 3, 5, 7 & 9 slot versions, supporting Gen 4/5 VPX backplanes. A total PSU power of up to 1075 watts may be installed. Custom modifications can be designed upon customer request.


Internal layout is divided into 4 independent metallic partitions. I/O section at the front, card-cage, PSU section & exhaust fans at the rear. This improves EMI/EMC performance & reduces PSU noise on system electronics.

Conventional "front-to-back" configuration allows for convenient application upgrade and expansion, keeping the same PSU, Front Panel and Fan Packs across systems. The chassis card-cage is designed for wedgelock IEEE P1101.2 conduction-cooled card types.

3U PENTAHEX-HP Performance



Slots / Pitch:3 | 5 | 7 | 9   1"

Sealed (Dry Air):

≤ 750W

The 3U PENTAHEX-HP chassis is suitable for very high wattage sealed applications that demand superior cooling capability and increased life-cycle scalability. This series of chassis provides the greatest expansion flexibility, system interoperability and lowest upgrade costs for advancing platforms.

PENTAHEX-HP - Chassis Global Thermal Resistance (CGTR):
PENTAHEX-HP 3 Slot: 420W Payload Power (ΔT/W = 0.071°C).
PENTAHEX-HP 5 Slot: 550W Payload Power (ΔT/W = 0.054°C).
PENTAHEX-HP 7 Slot: 650W Payload Power (ΔT/W = 0.046°C).
PENTAHEX-HP 9 Slot: 750W Payload Power (ΔT/W = 0.040°C).

For reliable operation it is recommended the maximum Payload Power not be exceeded. Subject to operating conditions. All CM 3U ATR chassis are delivered tested, qualified and certified per Military Standards MIL-STD-461G & MIL-STD-810H.

3U Backplanes

The CM PENTAHEX-HP series support only VPX backplanes. Bus slots are tailored for 1 inch pitch standard & deliver full compatibility with 0.8 inch pitch 3U modules.

CM-ATR-3U/ - Backplanes

CM enclosures incorporate a conduction-cooled slot card-cage that accepts all off-the-shelf Conduction Cooled 3U modules.

All 3U backplanes install specific TTL logic circuitry for driving up to 16 front panel user LED indicators.

All PENTAHEX-HP backplanes integrate a Chassis Supervisory System (CSS) for temperature (fans and heaters) and Power Supply control. Remote optoisolated control switches for ‘Battle-short’ & chassis PSU ‘on/standby’ are fitted as standard.

CM-ATR-3U/ - Backplanes
  • VPX backplanes conform to VITA 46 / 65 / 66 / 67 (≥ Gen 5).

CM 3U military backplanes allow unlimited pin I/O wiring capability. Flexible bottom wiring integration is facilitated by a standard 50mm bottom cavity clearance.

Class 1 military power input connectors fitted on the backplane offer shock & vibration reliability interconnectivity between chassis internal modules & allows high DC current rates with low voltage drops and minimum contact heating.

CM-ATR-3U/ - Backplanes

3U backplanes are supplied with military conformal coating. Printed circuits boards are partially coated per MIL-I-4658C. This is carried out only in areas in which coating the product does not affect VPX or I/O connectors.

All 3U models integrate the same backplane electronics for easy switch-overs, retrofits or replacement parts.
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3U PENTAHEX-HP Power Supplies

3U PENTAHEX-HP chassis PSUs support a wide variety of DC input voltages (MIL-STD-704 & MIL-STD-1275) and DC power output combinations up to 1075 Watts developed in alignment with the SOSA™ Technical Standard. Available in two high power versions according to number of system slots to suit the demand per DC Line of SOSA COTS Solutions.


All PSU models are fitted with Power Fail Monitor, remote voltage sensing, output voltage trim-up, time-delayed protection fuses, rear fan fuse and DC/DC converter remote shutdown.

To comply with MIL-STD-461G, a high capacity integrated EMI/EMC input voltage filter is fitted as standard on all 3U models. All models integrate the same PSU and backplane electronics.

DC PSUs are equipped with a VICOR military Filter and Attenuator Module (FIAM). This front-end device is fitted prior to the DC/DC converters to provide EMI filtering, inrush current limiting and transient protection.

3U PENTAHEX-HP Power Supply Unit

Front-end FIAM modules are protected against DC reverse polarity. An optional reverse polarity diode may be fitted in series with power connector input pin IN (+).

3U PENTAHEX-HP PSUs incorporate isolated DC/DC converters and oversized hold-up capacitors to ensure proper operation during short power line failures. Outputs are protected against short-circuit, thermal-shutdown etc. PSUs are custom made to match the enclosure mechanics.

The PSU in PENTAHEX-HP models is attached to a heat exchanger panel that provides both conduction and convection cooling. Internal air recirculation dissipates heat generated by the PSU through its panel via thermal conduction to the chassis frame.

Forced air that is drawn through the heat exchangers, passing over the PSU panel external fins & exhausted, removing the majority of heat.

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3U PENTAHEX-HP Rear Fan Assembly
Rear Fans
3U PENTAHEX-HP chassis fit twin Military PX3 fans as standard (-54°C to +125°C), delivering 200 to 400CFM.
LED Front Panel Indicators
Up to 8 front panel LED indicators for chassis monitoring; power on/off status, system board failure, input voltage, temp., etc.
3U PENTAHEX-HP Front Panel
Front Panel
Custom layout with client logo, connectors & silk-screening or a general purpose panel with MIL-C-38999 connectors is supplied.
3U PENTAHEX-HP Life-cycle Scalability
Product Flexibility
Optional Extended or Heat Exchanger covers can be selected for additional wiring clearance & are removable for easy maintenance.
3U PENTAHEX-HP Chassis Metalwork
Chassis Metalwork
Precision machined aeronautical aluminum with MIL-DTL-5541F chromate coating. All panels & joints incorporate EMI gaskets.
3U PENTAHEX-HP Mounting Tray
Mounting Tray
Low profile with quick release system offers easy insertion/removal capability, weight optimized with minimized dimensions.
EMI/EMC Filter
High capacity integrated EMI/EMC input voltage filter is fitted as standard on all 3U models to comply with MIL-STD-461F.
3U PENTAHEX-HP Internal Air Recirculation
Air Recirculation
All 3U chassis incorporate a low profile internal fan pack to recirculate air, improving card-cage, PSU & module heat dissipation.
3U PENTAHEX-HP Integrated Heat Pipes
Heat Pipes
Integrated heat pipes remove heat directly from the chassis card-cage, providing an "expressway" to the ambient environment.


  • Contaminant-free enclosure
  • VPX (1" Pitch)
  • Accepts Conduction-cooled 3U Modules only
  • Flexible Bottom I/O wiring
  • In-line EMI/EMC MIL-STD-461G Filter
  • Integrated Chassis Supervisory System (CSS)
  • 55°C less than conventional 3U ATRs
  • Dramatically increases payload MTBF by 8x*
  • Maintenance free operation
  • Front panel user indicators
  • Integrated Rear fan guards
  • Independent Fan & Power Supply input voltage
  • Stand alone low weight ATR
  • Internal card-cage airflow recirculation
  • Military Operating Temperature (-40°C | +85°C)
  • Customizable to specific requirements
  • Low Profile Mounting Tray with quick release
  • Manufactured with US MIL components
* Subject to operating conditions

3U ATR PENTAHEX-HP Specifications

WIDTH 155 mm 155 mm 155 mm 155 mm
HEIGHT 280 mm 280 mm 280 mm 280 mm
DEPTH 310 mm 361 mm 412 mm 463 mm
WEIGHT 6.2 Kg 7.4 Kg 8.2 Kg 9.0 Kg
CGTR COEFF ΔT/W = 0.071°C ΔT/W = 0.054°C ΔT/W = 0.046°C ΔT/W = 0.040°C
SLOTS 3 5 7 9
HEAT PIPES 4 - ⌀ 8mm 8 - ⌀ 8mm 12 - ⌀ 8mm 16 - ⌀ 8mm
PSU OUTPUT S-575W : +12 VDC @ 42A, +3.3 VDC @ 23A | S-1075W : +12 VDC @ 84A, +3.3 VDC @ 23A
PSU V-INPUT 28 VDC ±30%, 48 VDC ±30%, 72 VDC ±30%, 270 VDC ±30%
STD BACKPLANE 3U 1” pitch (3, 5, 7 & 9 slot) - MULTIGIG RT 3 - PCIe 16 Gbaud & 100 GBASE-KR4 (25.78125 Gbaud)
BOARD FORMAT CCS: Conduction-cooled slots only ANSI-VITA 48.2 boards
F115-400 200 CFM (Rotron PX3)
F200-400 400 CFM (Rotron PX3)
CM FRONT PANEL I/O 6 Power Pins (13 Amp) & 382 I/O Pins (5 Amp)
MTBF 25° GB 82,000 Hours, 65° AIC 27,000 Hours
OPERATING TEMP -40°C to +85°C Operating Temperature, -55°C to 100°C Storage Temperature


These highly optimized 3U chassis incorporate all proprietary technologies, features and well established mechanical & electrical solutions developed during the past 20 years.

FAC:Flow-through airflow open enclosure.

S:Standard sealed contaminant-free enclosure.

SEF-18HP:Sealed with Extended Fins + 18 Heat Pipes contaminant-free enclosure.

HES:Sealed contaminant-free enclosure fitted with 4 integrated heat exchangers as standard.

HES-FBL:Sealed, conventional front-to-back format contaminant-free enclosure fitted with 4 integrated heat exchangers as standard.

HES-FBL-HP:Sealed, conventional front-to-back format contaminant-free enclosure fitted with 4 integrated heat exchangers and heat pipes as standard.

3U ATR MIL Certificates

3U ATR Ordering Information

Generic Part Number:
CM-ATR-3U /CT /B /I /W /FP /TC /BC /F /G /C
/CT Enclosure Cooling Technique
  • CM-ATR-3U/PENTAHEX3-HP: Sealed, 3 Slot, 5 Heat Exchangers + 12 Heat Pipes.
  • CM-ATR-3U/PENTAHEX5-HP: Sealed, 5 Slot, 5 Heat Exchangers + 16 Heat Pipes.
  • CM-ATR-3U/PENTAHEX7-HP: Sealed, 7 Slot, 5 Heat Exchangers + 20 Heat Pipes.
  • CM-ATR-3U/PENTAHEX9-HP: Sealed, 9 Slot, 5 Heat Exchangers + 28 Heat Pipes.
/B Backplane Type
  • VPX: VITA 46 Military 3U VPX Backplane (1" Pitch).
/I PSU Input Power Voltage
  • 28VDC: 28 VDC Input.
  • 48VDC: 48 VDC Input.
  • 72VDC: 72 VDC Input.
  • 270VDC: 270 VDC Input.
/W Power Supply Unit
  • S-575W: SOSA™ Aligned (+3.3 VDC @23A, +12 VDC @42A)**.
  • S-1075W: SOSA™ Aligned (+3.3 VDC @23A, +12 VDC @84A)**.
** Power supply has been developed in alignment with the SOSA™ Technical Standard.
/FP Front Panel Layout
  • CMP: Standard CM front panel fitted with MIL-C-38999 connectors.
  • UDP: User defined front panel layout (requires customer drawing).
/TC Chassis Top Cover
  • HETC: Heat Exchanger Top Cover.
/BC Chassis Bottom Cover
  • HEBC: Heat Exchanger Bottom Cover (50mm wiring clearance).
/F Rear-mounted Fan Assembly
  • F115-400: 2x 100 CFM Rotron PX3 Military Fans fitted for 115 VAC @ 400Hz.
  • F200-400: 2x 200 CFM Rotron PX3 Military Fan fitted for 200 VAC 3-phase @ 400Hz).
/G Fan Finger Guards
  • EMIG: EMI shielding finger guards with honeycomb filter fitted as standard.
  • ANF: Optional finger guards with low acoustic noise filter (-4dB).
/C Chassis Color
  • B: Black, G: Navy Grey, E: Army Dark Earth, W: White, R: Red, PT: Platinum, YW: Yellow, GN: Green, BLU: Dark Blue, CR: Chromate MIL-C-5541 or O: Other (user defined).
Part Number Example:
  • 5 slot, 3U Avionics Enclosure.
  • Sealed, conventional front-to-back ATR with 5 Heat Exchangers, bottom cover, top cover, sidewalls & rear panel + Heat Pipes.
  • 5 slot, 3U VPX backplane.
  • 115VAC @ 400 Hz input power supply.
  • S-575W Power Supply (+3.3VDC @ 23A, +12VDC @ 22A).
  • User defined front panel layout (requires customer drawing).
  • Heat Exchanger Top Cover.
  • Heat Exchanger Bottom Cover (50mm clearance).
  • 2x 100 CFM 115 VAC @ 400 Hz Military Fan.
  • EMI shielded finger guards.
  • Enclosure color is black.