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Wall Industries, Inc.  |  Exeter, NH, USA

Next-Generation Open Frame Industrial Power Supplies: The OEM Sourcing & Engineering Manual

Discover how high-density open frame AC/DC power supplies solve real-world space, thermal, and compliance challenges in industrial automation, smart robotics, and heavy machinery. Built with US engineering rigor since 1961.

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60+ YearsUS Power Engineering History
1–3,600 WAC/DC Open Frame Range
Up to 95%Peak Energy Efficiency
Strategic Sourcing Guide

Why Global Procurement & Systems Engineers Choose Open Frame Industrial Power Supplies

As industrial systems compress in mechanical volume and expand in computing capabilities, hardware design teams face a permanent engineering tradeoff: delivering continuous high-wattage DC power without exceeding internal enclosure thermal thresholds or sacrificing board real estate. Open frame industrial power supplies have emerged as the foundational architecture to resolve this challenge.

An open frame industrial power supply is an un-enclosed AC/DC power conversion module engineered directly onto a single printed circuit board (PCB) or a minimal U-channel aluminum chassis. By eliminating heavy metal outer housings and dedicated fan enclosures, open frame power supplies deliver unmatched volumetric power density, exceptional thermal dissipation flexibility, and significant weight savings for OEM machinery.

In modern industrial environments—ranging from automated guided vehicles (AGVs) and semiconductor processing equipment to smart grid monitoring terminals and industrial edge servers—space inside the primary enclosure is extraordinarily limited. Open frame designs allow system engineers to place power conversion directly adjacent to the payload circuitry, utilizing system forced-air cooling or conduction heat sinks to manage thermal loads efficiently.

From a procurement perspective, open frame power units lower the Total Cost of Ownership (TCO). Standardized footprint dimensions—most notably the industry-standard 2" x 4", 3" x 5", and 4" x 7" footprints—allow engineering teams to dual-source power supplies and simplify chassis assembly. Sourcing qualified open frame units from established power partners also dramatically accelerates system-level safety certification under safety frameworks such as IEC/EN/UL 62368-1 and IEC/EN 60601-1.

At Wall Industries, Inc., our US-based power conversion specialists in Exeter, New Hampshire have spent over six decades perfecting open frame power supply topologies. Whether your project demands standard off-the-shelf components, modified connectors and potting, or a ground-up custom OEM solution, Wall Industries provides the engineering expertise, quality guarantees, and supply chain continuity essential for high-reliability industrial deployment.

Recommended Open Frame Platforms

High-Performance Open Frame Industrial Power Supplies

Engineered for maximum reliability, extreme thermal resilience, and strict regulatory compliance in harsh operating environments.

High-Density AC/DC Open Frame Power Supply Unit

Ultra-Compact 2" x 4" AC/DC Open Frame Series

40 to 250 Watts

Designed for compact industrial enclosures, IoT gateways, and robotics control units requiring low-profile single and multi-output DC power.

  • Universal AC Input: 85VAC to 264VAC with active Power Factor Correction (PFC > 0.95)
  • High Power Density: Up to 20W/in³ in an industry-standard 2" x 4" footprint (1U profile height)
  • No-Load Power Consumption: < 0.15W meeting strict green energy efficiency standards
  • Operating Temperature: -40°C to +85°C with advanced thermal derating capabilities
  • Protections: Over-Voltage (OVP), Over-Current (OCP), Short-Circuit (SCP), and Over-Temperature (OTP)
2x4 Standard Footprint1U Low ProfileActive PFCClass I / Class IIIEC 62368-1 Approved
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Conduction Cooled Industrial Open Frame Power Supply

U-Channel Conduction-Cooled Heavy Duty Series

300 to 1,200 Watts

Engineered for sealed, fanless industrial enclosures where forced-air cooling is impossible due to dust, moisture, or acoustic noise constraints.

  • Baseplate Conduction Cooling: Eliminates cooling fans while providing 100% rated output power
  • Peak Power Handling: Delivers up to 150% peak load for 5 seconds for inductive motor drives
  • High Isolation Rating: 4,000VAC input-to-output isolation with 2xMOPP options available
  • EMC Performance: Built-in EMI filter meeting EN 55032 / CISPR32 Class B radiated emissions
  • Ruggedized Architecture: Conformal coating options for dust and humidity protection
Fanless ConductionU-Channel MountingPeak Load SupportHigh IsolationHarsh Environment
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Engineering Selection Criteria

Open Frame vs. Enclosed vs. DIN Rail: Mechanical & Thermal Comparison

Selecting the optimal power supply architecture depends on system cooling mechanism, internal space, IP rating, and structural mounting requirements.

System-level trade-offs for industrial power supply mechanical formats. Standard values provided for baseline engineering selection.
Evaluation Vector Open Frame Industrial Enclosed Metal Cased DIN Rail Mount
Power Density (W/in³) High to Very High (Up to 25 W/in³) Medium (10 - 15 W/in³) Low to Medium (5 - 10 W/in³)
Thermal Dissipation System Fan / Conduction Plate Self-contained Fan / Vent Holes Natural Convection Chimney Airflow
Environmental Protection Requires Primary Outer Enclosure Basic Mechanical Protection Cabinet Installed (IP20 standard)
System Mounting Direct Standoffs onto System Chassis Internal Screw Mount / Flange Standard 35mm TS-35 DIN Rail
Initial Unit Cost (TCO) Lowest Cost (Minimal Metal) Moderate Higher (Includes DIN Clip & Housing)
EMC Shielding Relies on System Enclosure & PCB Layout Self-Shielded Outer Metal Shell Cabinet Shielded
Technology Evolution

Industrial Power Development Trends: Meeting Industry 4.0 Demands

The acceleration of Industry 4.0, autonomous mobile robots (AMRs), high-speed vision inspection, and AI edge computing is transforming how power supplies are designed and specified.

Peak Load Capabilities for Dynamic Loads

Modern industrial equipment rarely operates at steady-state current. Stepper motors, electromechanical solenoids, print heads, and pneumatic actuators demand brief power spikes during startup or acceleration. Legacy power supplies required oversized wattage ratings just to handle short load spikes, increasing hardware cost and mechanical size.

Next-generation open frame industrial power supplies integrate advanced current-limit controllers capable of delivering 150% to 200% peak power for up to 5 seconds. This allows system designers to specify a power supply matched to the continuous power demand while relying on the unit’s peak headroom to ride through dynamic motor surges safely.

Class I & Class II Insulation Versatility

Industrial deployment scenarios frequently span grounded metal control cabinets (requiring Safety Class I power supplies with Safety Earth ground) and isolated plastic enclosure equipment (requiring Class II double-insulated power supplies without earth ground). Modern open frame units are designed to meet both Class I and Class II installation standards, allowing single power platform standardization across diverse end-product lines.

Electromagnetic Compatibility (EMC) Engineering

Operating an unshielded open frame power supply inside a dense electronic cabinet presents complex EMC challenges. High switching frequency harmonics can couple into system wiring or radiate into delicate data lines. Leading power supply designs utilize multi-stage EMI filters, low-noise resonant topologies (such as LLC or Active Clamp Flyback), and optimized PCB ground planes.

Wall Industries designs open frame industrial power supplies that achieve CISPR 32 / EN 55032 Class B conducted and radiated emissions margins even when tested in open-chassis conditions, ensuring your final product passes regulatory compliance on the first submission.

Thermal Derating & Extended Lifetime Components

Power supply longevity is governed by thermal stress on critical electrolytic capacitors. Wall Industries applies conservative engineering derating rules—selecting long-life 105°C rated Japanese aluminum electrolytic capacitors and solid polymer capacitors—ensuring mean time between failures (MTBF) exceeding 500,000 hours under Bellcore/Telcordia standards.

1961Established Power Engineering Leader
3,600 WMaximum AC/DC Open Frame Power
500k+ HrsCalculated MTBF Reliability
100%Custom & Modified Capability
Custom Power Supply Engineering Excellence The Wall Industries Advantage

60+ Years of Engineering Excellence in Open Frame Power Conversion

Since 1961, Wall Industries, Inc. has engineered and manufactured mission-critical power supplies that keep industrial infrastructure, medical devices, defense systems, and transportation networks operating flawlessly worldwide.

Our headquarters in Exeter, New Hampshire houses a full engineering team specialized in power topologies including flyback, forward, LLC resonant, push-pull, buck, boost, and bridge circuits. Rather than forcing your equipment to fit an off-the-shelf product catalog, we specialize in modified-standard and fully custom power supply design.

When you partner with Wall Industries, you gain direct access to US applications engineers who review your electrical schematics, mechanical envelope, thermal constraints, and regulatory standards. We evaluate input surge levels, isolation barrier creepage, hold-up times, and output ripple parameters before recommending or engineering a unit for your bill of materials.

Our open frame industrial power supplies undergo exhaustive qualification testing, including HALT (Highly Accelerated Life Testing), HASS, environmental thermal shock from -55°C to +125°C, high-voltage dielectric withstand, and automated ATE burn-in cycles. This ensures that every unit delivered to your assembly line performs reliably over decades of continuous operation.

Whether you require a minor wiring harness modification on a standard 2x4 open frame supply or a complete custom multi-channel AC/DC power system, Wall Industries delivers prototype turnarounds and multi-year production stability backed by robust anti-counterfeiting and quality control protocols.

Proven Field Experience

Over six decades powering water treatment plants, smart grid hardware, industrial automation, medical diagnostics, and military ground systems—proven in over 3,000 active customer programs.

In-House Technical Expertise

Direct technical support from experienced power electronics engineers in New Hampshire. No off-shore call centers or generic sales representatives.

Rigorous Quality & Trust

Full compliance documentation, traceably sourced components, anti-counterfeit component controls, and commitment to long product lifecycles to protect your legacy designs.

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Target Applications

Where Open Frame Industrial Power Supplies Excel

From cleanroom semiconductor fabs to rugged heavy-equipment cabs, open frame power supplies deliver compact, efficient power conversion across diverse industries.

Industrial Automation Power Supplies Industrial Automation PLC controllers, robotic arms, sensor hubs, and human-machine interface (HMI) screens Medical Power Supplies Medical Devices Diagnostic equipment, patient monitors, and laboratory automation with 2xMOPP isolation Military Power Supplies Military & Defense Rugged communications gear, radar sub-assemblies, and vehicle tactical displays Railway DC/DC Converters Railway & Transit On-board ticketing systems, passenger Wi-Fi gateways, and wayside signal controllers LED Power Supplies Commercial Lighting High-bay LED arrays, architectural lighting controllers, and outdoor luminaire ballasts Electric Vehicle Power Supplies EV Infrastructure Auxiliary power for DC fast chargers, battery management systems, and EVSE control boxes
Robotics Power Components Robotics & AGVs High peak power open frame units driving servo motors and lidar navigation arrays
Telecommunication Edge Servers Telecom Edge Nodes 5G small cells, optical network terminals, and remote base station routers
Technical FAQ

Open Frame Industrial Power Supplies: Procurement & Engineering Answers

Direct technical answers to common questions asked by system hardware engineers, sourcing managers, and procurement specialists during power supply evaluation.

An open frame industrial power supply consists of an unshielded printed circuit board (PCB) assembly containing all AC/DC power conversion circuitry, components, and termination connectors without a protective outer metal box or self-contained cooling fan. In contrast, an enclosed power supply houses the PCB inside a ventilated metal cover or sealed chassis.

Open frame power supplies are selected when the unit will be mounted inside a protective system outer enclosure where space is tight, weight must be minimized, and system forced air or conduction cooling is already present. This yields higher volumetric power density and lower overall unit cost.

Thermal management for open frame power supplies in sealed enclosures requires evaluating three key vectors:

  • Convection Airflow: Maintain at least 10mm to 15mm clearance above and around components to allow natural thermal convection currents.
  • Forced Air Rating vs. Convection Rating: Most open frame datasheets publish two power limits—for example, 150W with 10 CFM forced airflow, but only 100W under still natural convection. Ensure your system design reflects the correct airflow profile.
  • Conduction Baseplate Cooling: In fanless sealed enclosures, select a U-channel or conduction-cooled open frame model. Secure the aluminum baseplate directly to the system enclosure wall using thermally conductive gap pads or thermal grease to conduct heat outward.

Primary industrial compliance standards include:

  • IEC/EN/UL 62368-1: The unified safety standard for Audio/Video, Information, and Communication Technology Equipment (which replaced IEC 60950-1 and IEC 60065).
  • EN 55032 / CISPR 32 Class B: Standard for conducted and radiated electromagnetic compatibility (EMC).
  • IEC 61000-4-2/3/4/5/6: Immunity tests covering ESD, radiated RF, electrical fast transients (EFT), surge immunity (up to 2kV/4kV), and conducted disturbances.
  • IEC 60601-1 (Medical): Required if the open frame supply is deployed in medical diagnostics or patient-proximity equipment (2xMOPP isolation).

A modified-standard power supply begins with a pre-certified standard catalog open frame platform and alters specific features to match your OEM system—such as non-standard DC output voltage tuning (e.g., 28V instead of 24V), customized molex/JST wiring harnesses, conformal PCB coating, or custom mounting bracketry.

The key advantages are dramatically reduced engineering development costs (NRE), significantly faster prototyping (weeks instead of months), and simplified safety re-certification because the core circuit topology and high-voltage isolation transformers are already safety tested.

Active Power Factor Correction (PFC) shapes the AC input current wave to match the input voltage phase, bringing the power factor close to unity (PF > 0.95 to 0.99). In industrial facilities operating hundreds of electrical loads, active PFC prevents harmonic distortion on the AC grid, reduces reactive power losses, lowers AC line currents, and ensures compliance with harmonic current emissions standard IEC/EN 61000-3-2.

Yes. On request, Wall Industries engineers custom and modified open frame power supplies rated for extreme operating environments from -55°C cold startups up to +125°C ambient temperatures. We utilize military-grade derating guidelines, high-temperature silicon semiconductors, ceramic/polymer capacitors, and specialized potting or conformal coatings to ensure faultless operation under environmental extremes.

Hold-up time is the duration a power supply can maintain output DC voltage within regulation after a complete loss of AC input power. Standard industrial open frame power supplies provide 16ms to 20ms hold-up time at full load (equivalent to one full AC line cycle at 50Hz/60Hz). This gives system microcontrollers enough time to store critical data, initiate a safe shutdown, or transition to a secondary uninterruptible power supply (UPS).

Wall Industries understands that industrial OEM capital equipment often stays in active production for 10 to 20+ years. We support extended product lifecycles and avoid premature component End-of-Life (EOL). If an internal component becomes obsolete, our New Hampshire engineering team performs form-fit-function re-engineering so your product line continues uninterrupted without requiring a costly redesign of your master system assembly.

Request an OEM Open Frame Power Supply Quote Today

Connect directly with our Exeter, New Hampshire power conversion engineers. Submit your electrical, mechanical, and thermal parameters for a rapid quote, sample evaluation, or custom modification proposal.

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