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Rugged Power Distribution Units

Meeting Power Needs in
Challenging Environments

“Rugged” can mean very different things to different people. From a little beefier than normal, to moderately robust, to military front line ready. Conditions range from minor vibration or splashing of water, to extreme temperatures, exposure to harsh weather, dirt, and frequent significant shock and vibration. These environments can affect the components, the assembly, and even compatibility with power sources prone to sags, surges, and other irregularities.

Rugged PDUs differ from commodity PDUs in using more-robust materials, tougher components, and assembly techniques all designed to handle the conditions noted above. Rugged PDUs will often need to integrate surge suppression, EMI filters, isolation transformers, and other tools to mitigate the severity of noisy power signals caused from non-grid power sources. Selecting these components requires an understanding of the types of irregularities expected in the environment, and matching various attributes of the components to the power being conditioned.

Marway has been meeting the needs for rugged PDUs in non-military and military applications for over 30 years.

What to look for in a rugged PDU

  • Provides a rigid foundation for components and connections with a sturdy chassis.
  • Incorporates assembly techniques learned through support of multiple rugged applications over years.
  • Meets environmental needs through proven testing to military, NEMA, and other standards.
  • Protects downstream equipment from noisy power sources using EMI filters, surge suppressors, and other techniques.

What to look for in a PDU supplier

  • Takes the time to understand the application, explore needs, and consider design options.
  • Optimizes the selection of application-specific components for capacity matching, packaging efficiency, and cost.
  • Designs and manufactures enclosures to meet unique needs for installation, cable routing, and other integration details.
  • Manages the entire process of standards testing and certification, when required, prior to delivery.

Platforms and applications

  • Naval surface vessels, submarines, and small craft. Recreational marine craft.
  • Aircraft, aerospace research, ATE, and simulators.
  • Mobile camps and forward bases.
  • Supporting communications, weapons, intelligence, and research systems.
  • Currently integrated into CSRR, AMDR, VPM, BACN, WIN-T, and other programs.

Compliance and standards

  • General MIL-STDs 461, 810, 901, 167, and others.
  • Platform-specific MIL-STDs 1399, 704, and 1275.
  • UL and CE certification (others when required).
  • Marway is certified AS9100 with ISO 9001.

Custom and standard

  • Marway specializes in design and manufacture of custom PDUs such as those for rugged environments.
  • Rackmount chassis from 0U to 24U, to rack sized.
  • Custom enclosures for non-rack applications.
  • Ac, dc, up to 600 volts, 400 amps.
  • For moderate-duty applications, our standard products, or updates to an existing product may be more cost effective.

Integrated conditioning, conversion, and control

  • Reduce EMI using filters and other techniques.
  • Mitigate voltage spikes/transients using surge suppression.
  • Integrate ac and dc sources into a single system.
  • Use conversions of ac-ac, ac-dc, dc-dc, and dc-ac to create needed power forms.
  • Optimize local and remote power monitoring and switching.
  • Improve safety with EPO and interlock circuit integration.

Networked or non-networked controls

  • Non-networked PDUs still offer some remote switching through discrete signals from remote panels.
  • Networked PDUs offer remote outlet switching and power monitoring over HTTP/S, SSH, Telnet, and SNMP.
A photo collage representing applications for rugged PDUs in military vehicles, mobile camps, and other harsh environments.
Marway rugged PDUs are used in many applications. We’ve provided power distribution units for ships, submarines, and small water craft. Our units are used in key airborne communications infrastructure and development platforms. Marway’s PDUs have also been deployed in numerous mobile camp environments.
A photo of a military pdu in a small, rugged transit case. A photo of the top of a power distribution rack built to military specifications for shock and vibration for a combat ship application.
Marway’s rugged PDU designs range from non-rackmount, custom enclosures, to portable transit case systems, to full-rack-sized power distribution systems for industrial environments and large platforms such as ships.
Illustrated graphic badges indicating that Marway is certified ISO 9001 with AS 9100, builds and certifies products to UL and CE standards, and can meet the requirements of MIL-STD 461, MIL-STD 810, MIL-STD 901, MIL-STD 167, MIL-STD 1399, MIL-STD 704, MIL-STD 1275 and others. Additionally, Marway is TAA, ITAR, and NIST compliant.

What is a Rugged PDU?

A rugged PDU is an electrical power distribution unit designed to provide stable power and meet the demanding needs of harsh environments. For many applications this means operating in conditions with vibration, shock, dirt, extreme temperatures, and even all weather. Many rugged PDU features will vary based on the target application, but will include at least a sturdy chassis and assemby techniques to stand up to minor vibration and shock. Components and materials can be used to increase the tolerance of extreme temperature ranges. Panel controls, connectors, and access panels can be sealed to protect the inside of the PDU from intrusion of liquids, sand, or excessive environmental dust.

Even with all of the measures to make the PDU physically tough, its job is still power distribution. A harsh physical environment is usually coupled with a harsh electrical environment. A rugged PDU will often need to include capabilities to clean up noisy power signals, integrate mixed power forms, and the unique connectivity and controls needed in these unique applications.

Key Capabilities of Rugged Environment PDUs

  • Handles harsh environment conditions such as virbration, shock, dust, rain, ice, heat, and others.
  • Optionally built and certified to MIL-STD 461, 901, 810 and other standards.
  • Reduces or eliminates conducted and inducted electro-magnetic interference (EMI) from nearby electrical equipment.
  • Protects against voltage spikes created by equipment on the same lines, and lightening strikes near outside transmission lines.
  • Integrates remote interlocks to cut power to outlets to meet safety requirements.
  • Creates multiple power forms from a single facility power source such as higher or lower voltages, or even dc power from ac power and vice versa.
  • Adopts the use of specialized connectors and outlets to interface to existing customer equipment, safety systems, and more.
A rugged application PDU designed to handle the demanding electrical, environmental, and control needs of industrial applications. A Marway 532 PDU exhibiting some of the features found in industrial PDUs.
Threaded circular connectors (upper image) are used to ensure connection reliability during constant vibration and occasional shocks, and can protect against sand, moisture, and even pull stress. Industrial twist lock connectors (lower image) can also be used for lighter-duty applications in industrial environments.

Cleaning Up Noisy Power

Noisy power signals occur in just about every environment due to the varying loads of nearby equipment. Like sudden opening and closing of water valves can cause pressure surges, sudden surges of “pressure” and “flow” (voltage and current) in electrical lines cause signal abnormalities. Where a weak fitting along a pipe might leak, a vulnerable component in an electronic system may fail. Noisy power also creates heat in many components. Components suffer early component failures from constant overheating, and shorts result from the break-down of insulation.

Most commodity PDUs are designed for office-like environments where there is little influence on power signals from nearby equipment. At most, these PDUs may have some surge protection since those devices are relatively low cost and small.

Rugged PDUs integrate surge suppression, EMI filters, isolation transformers, and other tools to mitigate the severity of noisy facility power signals coming from many different sources. Selecting these components requires an understanding of the types of noise which are expected in the environment, and matching various attributes of the components to the power form being conditioned.

A photo of an EMI filter integrated into a custom PDU.
EMI filters, surge suppressors, isolation transformers, and more can be integrated into a custom rugged PDU to mitigate noise problems. Many of Marway’s standard products also include EMI filters and surge suppressors.

Creating Needed Power Forms

Many environments needing a rugged PDU also need a mixture of different power forms. A power form is the combination of specifications for voltage type, voltage rating, and current rating. For example, 120 Vac, 15 amps vs. 80 Vdc 60 amps are two different power forms.

A building’s facility power, a ship’s power system, or a mobile camp’s power generation will usually be wired for only one or two primary forms. This might be three-phase ac power for most areas. In various applications, there may be a need for more types of power. Ac may be needed in multiple three-phase and single-phase forms. Different voltages may be needed to serve the larger and smaller pieces of equipment. Even dc power is often needed in the same work spaces as ac power.

The PDU which will already be needed for distribution, is a convenient and efficient place to integrate transformers, power supplies, and power converters to create multiple power forms from a single facility or generated source. This can simplify installation, and provide better control options compared to having multiple power services wired throughout a facility.

A photo of power conversion and conditioning components consolidated into one PDU enclosure.
Power transformers, power supplies, and power converters are often integrated into rugged PDUs to provide distribution of various ac and dc power forms to the target work area.

Meeting Exact Control and Connection Needs

Marway’s custom PDUs offer a wider range of circuit designs, control features, power monitoring, and even remote management capabilities. Most commodity power distribution products have a single circuit serving all outlets with perhaps an on/off switch or breaker. Industrial and military environments often require more control over multiple individual circuits. For many applications, digital power displays are important. Indicators for the status of specific circuits and interlocks are simple additions, but unique to each application. Adapting to these unique switching, display, and control needs, is a key capability for Marway’s rugged PDUs.

Another area of important flexibility for a rugged PDU is that of cable connectors. In the industrial and military realm, there are hundreds of unique connectors. Each PDU has to integrate to the application’s need for safety end environmental features like resistence to water, vibration, and more. Control signal connectors are even more varied.

Panel controls and switches may need guards to protect against accidental bumping in tight or unstable environments. Protection and sealing against liquids, dirt, and dust may require special components or housings.

Industrial PDUs, like Marway’s 5 and 8 Series, can be customized with specialty connections and controls, but ultimately most rugged applications will benefit from a custom design.

A collage of various connectors and controls used on industrial PDUs.
Rugged PDUs often require specialized connections and controls which would not be included on general-purpose commercial products.