MIL-STD-810 – Vibration, Shock and Environmental Conditions in Military Power Supplies

A power supply designed for a military system must withstand much more than just input voltage, output power and efficiency requirements.

When a power supply is installed in a military vehicle, airborne system, mobile platform or equipment operating under field conditions, it may also be exposed to vibration, shock, extreme temperatures and harsh environmental conditions.

This is where MIL-STD-810 becomes relevant.

MIL-STD-810 is a U.S. military standard addressing the effects of environmental conditions on equipment throughout its life cycle and the methods used to test its ability to withstand those conditions. The current active version is MIL-STD-810H Change 1, dated May 18, 2022.

For power supplies and DC-DC converters, the standard is particularly relevant to areas such as Vibration, Shock, High Temperature, Low Temperature and Temperature Shock, although it actually covers a much broader range of environmental conditions.

It is particularly important to understand that MIL-STD-810 does not define a single uniform test that every power supply must pass.

The standard uses an Environmental Tailoring approach, in which test conditions are tailored to the environment in which the equipment is expected to operate. The U.S. Department of Defense also explicitly states that the standard does not, by itself, impose fixed design or test specifications, but rather provides processes and methods for developing realistic environmental requirements based on the intended application.

Therefore, the statement:

MIL-STD-810 Compliant

does not necessarily provide complete engineering information on its own.

When evaluating a military power supply, it is important to know which test methods were performed, under what conditions, at what severity levels and in what mounting configuration.

Why Is MIL-STD-810 Particularly Important for Power Supplies?

A power supply is an electronic system, but its ability to withstand environmental conditions depends to a large extent on its mechanical and thermal design.

A power supply typically contains components with relatively significant mass, such as transformers, inductors, capacitors, power components, connectors and heat sinks. When the system is exposed to vibration or shock, mechanical forces act on these components, the PCB, solder joints and enclosure.

At the same time, the power supply must dissipate the heat generated by its internal power losses.

In many military systems, it is not possible to rely solely on natural airflow or a fan. Some power supplies therefore use Conduction Cooling, transferring heat to the baseplate and from there to the system chassis, a heat sink or a Cold Plate.

As a result, the mechanical and thermal design of a military power supply are closely interconnected.

The enclosure must be rigid enough to withstand Vibration and Shock, while in many designs it also forms part of the thermal path used to conduct heat away from the power supply.

This is one of the reasons why selecting a military power supply cannot be reduced to a single question:

What is the operating temperature range of the power supply?

It is also necessary to consider how the power supply is mounted, how heat is dissipated and what temperature applies at the relevant thermal reference point.

Three Key Areas: Vibration, Shock and Temperature

For power supply applications, environmental requirements can be considered in three key areas:

Vibration – Continuous or Repetitive Mechanical Vibration
Vibration generated by engines, road conditions, drive systems, propellers, motors or the structure of the platform itself.

Shock – Mechanical Shock
Short-duration, high-acceleration events that may occur, for example, during off-road operation, landing, mechanical impact, transportation or other platform-dependent events.

Temperature – Temperature and Thermal Management
The ability of the power supply to operate or survive at high and low temperatures while also safely dissipating the heat it generates internally.

These three areas are not independent of one another.

Vibration affects the mechanical design, the mechanical design affects how the power supply can be mounted to the system, and the mounting method directly affects both Conduction Cooling and the temperature of the power components.

For this reason, in a military power supply, Mechanical Design and Thermal Design should be considered as one integrated system.

Vibration in Military Power Supplies

Vibration is one of the key mechanical challenges for electronic equipment installed on military platforms.

The source of vibration varies depending on the application. In a military vehicle, vibration may originate from the engine, drivetrain and off-road operation. In an airborne system, it may originate from engines, propellers, rotors or the aircraft structure itself.

The nature of the vibration is not necessarily the same in every application.

Equipment may be exposed to vibration at different frequencies and amplitudes, and sometimes to a broad frequency spectrum that changes over time. Therefore, Vibration testing is not simply a matter of applying “strong vibration” to a product. The test should represent, as closely as practical, the environment in which the equipment is expected to operate.

In MIL-STD-810, vibration is addressed under Method 514.8 – Vibration.

The purpose of the test is to evaluate whether the equipment can withstand the vibration exposure expected throughout its life cycle and continue to perform as required after exposure and, where applicable, during the test itself.

What Can Be Damaged Inside the Power Supply?

When a power supply vibrates, it is not only the external enclosure that moves.

Every component within the system is affected by the motion.

This is particularly significant for components with relatively high mass, such as:

• Transformers
• Inductors
• Large capacitors
• Connectors
• Heat sinks
• Power components
• PCBs and internal assemblies

The greater the mass of a component and the weaker its mechanical support, the more significant the forces acting on its connection to the PCB or mechanical structure can become.

Over time, vibration can cause mechanical fatigue, loosening of connectors and fasteners, cracks in connections and solder joints, PCB damage or changes in electrical contact integrity.

A power supply intended for a military environment therefore requires a mechanical design that considers not only the strength of the enclosure, but also how internal components are secured and supported.

Depending on the design and application, techniques such as additional mechanical support, Staking, Potting, securing heavy components and proper design of mounting points may be used.

Resonance – When Vibration Frequency Meets the Structure

One of the important considerations in vibration testing is Resonance.

Every mechanical structure has natural frequencies at which it tends to vibrate. When the frequency of an external excitation approaches a natural frequency of part of the system, the local motion can become significantly greater than the motion applied externally to the product.

For example, the enclosure as a whole may appear extremely rigid, while an internal PCB, a heavy component or a particular mechanical element may behave very differently at a specific frequency.

This is one reason why vibration resistance cannot be determined simply by the thickness of the enclosure material.

The entire system must be considered:

Enclosure → Mounting → PCB → Components → Connections

The internal mechanical design is just as important as the external enclosure.

Shock – Mechanical Shock

Vibration and Shock both belong to the mechanical environment, but they are not the same.

Vibration is generally a continuous or repetitive mechanical load over time.

Shock, in contrast, is typically a relatively short-duration event in which the system is subjected to rapid changes and high acceleration.

In MIL-STD-810, shock is addressed under Method 516.8 – Shock.

Shock events may occur, depending on the platform and product life cycle, during transportation, handling, operation over rough terrain, landing or other mechanical events.

During such a short-duration event, significant forces can act on internal components.

A heavy component that is not properly secured can impose a high load on its mounting points. Connectors, PCBs and heat sinks can also become potential points of failure.

Here too, it is not enough for the external enclosure simply to look Rugged.

Vibration vs. Shock

The distinction between Vibration and Shock is important when designing a power supply.

Parameter	Vibration	Shock
Nature of event	Continuous or repetitive	Short and rapid
Primary effect	Fatigue, resonance and loosening over time	High instantaneous load
Sensitive areas	PCBs, solder joints, components and connectors	Heavy components, connections and mounting points
General example	Engine or vehicle vibration	Impact, landing or short mechanical event

A product may withstand long-term vibration very well while remaining sensitive to a severe shock event, or vice versa.

Therefore, when a specification requires compliance with MIL-STD-810, it is important to understand exactly what was tested rather than relying only on the general name of the standard.

The Mounting Configuration Is Also Part of the System

There is another point that is easy to overlook: a power supply does not operate in isolation.

It is attached to the platform using screws, rails, flanges, a Baseplate or another mounting method.

The way the power supply is mounted affects how mechanical forces are transferred from the platform into the enclosure and internal components.

For this reason, the mounting configuration used during a Vibration or Shock test is an important engineering parameter.

A power supply tested while secured in one specific configuration does not automatically represent every possible installation method.

The same mounting interface becomes even more important when the power supply uses Conduction Cooling.

In this case, the mechanical interface between the power supply and the platform is responsible for more than simply securing the unit.

It may also serve as the primary thermal path for removing heat from the power supply.

This is where two design disciplines that are difficult to separate in military systems come together:

Mechanical Design + Thermal Design

ממשיך. כאן אני גם מיישם את התיקון שדיברנו עליו: במקום לומר שפחות חום עשוי לאפשר Baseplate קטן יותר, הניסוח המדויק יותר יהיה שהוא מפחית את העומס התרמי על ה-Baseplate ועל מערכת הקירור.

Temperature – Extreme Temperatures in Military Power Supplies

Temperature is one of the most significant factors in the design and selection of a power supply for a military system.

Unlike Vibration and Shock, which primarily originate from the platform and its mechanical environment, temperature introduces two sources of heat that must be considered:

The environment in which the power supply is installed, and the heat generated by the power supply itself.

No power supply is 100% efficient. Some of the electrical energy is converted into heat within the unit. Therefore, as power increases and efficiency decreases, the amount of heat that must be dissipated increases.

For example, a power supply delivering 500W at 90% efficiency requires approximately 556W of input power.

This means that approximately 56W is converted into heat inside the power supply.

In a compact, enclosed system, 56W of heat is far from insignificant.

High Temperature and Low Temperature

MIL-STD-810 includes dedicated test methods for extreme temperatures, including:

• Method 501.7 – High Temperature
• Method 502.7 – Low Temperature
• Method 503.7 – Temperature Shock

These tests are intended to evaluate the effects of relevant temperature conditions on the equipment. However, this does not mean that every product is automatically tested over the same temperature range or using the same temperature profile.

The requirements should be tailored to the expected environment and life cycle of the system.

It is also important to distinguish between several temperature specifications commonly found in power supply datasheets:

Operating Temperature – The temperature range within which the power supply is designed to operate.

Storage Temperature – The temperature range within which the product can be stored while not operating.

Start-Up Temperature – The temperature at which the power supply is capable of starting and operating correctly.

These ranges are not necessarily the same.

A power supply may be capable of surviving extremely low temperatures during storage but may not be designed to start up at that same temperature.

Ambient Temperature Is Not Always the Most Important Parameter

When reading a power supply datasheet, it is easy to focus on a specification such as:

Operating Temperature: -40°C to +85°C

However, this figure alone can be misleading if it is not clear where and how the temperature is measured.

For an air-cooled power supply, ambient temperature and airflow may be key parameters.

For a power supply designed for Conduction Cooling, however, the more important parameter may be the Baseplate Temperature.

In other words, the question is not only:

What is the temperature inside the system?

It is also:

At what temperature can the cooling surface to which the power supply is mounted be maintained?

Conduction Cooling – Heat Dissipation Through Conduction

In many military systems, relying on an internal fan is undesirable and, in some cases, impractical.

A fan adds a mechanical component to the system, consumes power, requires an airflow path and, in non-sealed systems, may introduce dust and contamination.

In addition, sealed enclosures or densely packed systems may not provide sufficient airflow around the power supply.

One way to address this challenge is Conduction Cooling.

In this approach, a thermal path is designed to transfer heat from the power components to the mechanical structure of the power supply and from there into the system in which it is installed.

In simplified form, the thermal path can be represented as:

Power Components → Thermal Interface → Baseplate → Chassis / Cold Plate → Environment

Every part of this thermal path matters.

If the thermal contact between the Baseplate and the chassis is poor, even a well-designed power supply may reach higher internal temperatures than intended.

The Mounting Surface Is Part of the Cooling System

This is particularly important for the engineer integrating the power supply into the system.

In a Conduction-Cooled power supply, the Baseplate is not simply the bottom of the enclosure.

It is a thermal interface.

Factors that may therefore be important include:

• Contact area between the power supply and chassis
• Flatness of the mounting surface
• Thermal Interface Materials
• Clamping pressure
• Location and arrangement of mounting screws
• The ability of the chassis to transfer heat away
• Cold Plate or Chassis temperature

If the chassis itself is already at a high temperature, the ability of the power supply to transfer heat into it is reduced.

Therefore, selecting a power supply rated for high-temperature operation is not enough. The system to which it is mounted must also be capable of providing the thermal conditions on which the power rating is based.

Derating – Full Power Is Not Always Available at Every Temperature

Another important consideration is Thermal Derating.

A power supply rated at, for example, 500W may not necessarily be capable of delivering 500W throughout its entire specified temperature range.

In some products, the allowable output power must be gradually reduced above a certain temperature.

For example, a datasheet may specify full-power operation up to a certain Baseplate Temperature and require a reduction in output power above that point.

Therefore, when selecting a military power supply, it is important to consider not only:

Maximum Output Power

but also the Derating Curve and the conditions under which the full-power rating is valid.

Why Is Efficiency Important to Mechanical and Thermal Design?

High efficiency is not only about reducing power consumption.

It directly affects the amount of heat that the system must dissipate.

Returning to the example of a 500W power supply:

At 90% efficiency, the power loss is approximately 56W.

At 95% efficiency, the power loss drops to approximately 26W.

In this example, an improvement of five percentage points in efficiency reduces the amount of heat that must be dissipated by more than half.

In a sealed or densely packed military system, this can make a significant difference.

Less heat reduces the thermal load on the Baseplate and cooling system and can help maintain lower component temperatures.

Therefore, Efficiency, Thermal Design and Mechanical Integration are closely interconnected.

Mechanical and Thermal Design Meet at the Same Baseplate

This brings us back to a point discussed in the Vibration and Shock sections.

The same Baseplate used to transfer heat from the power supply to the chassis often also serves as the mechanical structure through which the power supply is attached to the platform.

This means that the same interface may need to perform two functions:

Mechanical: Transfer and withstand the forces generated by Vibration and Shock.

Thermal: Transfer heat from the power supply into the Chassis or Cold Plate.

A properly designed military power supply does not treat these two requirements independently.

The mechanical solution affects the thermal path, and the thermal solution affects the mechanical mounting configuration.

Therefore, when integrating a power supply into a system, the following should be considered together:

Power + Mechanical + Thermal

as one integrated system.

ממשיך עם יתרת המאמר באנגלית. תיקנתי גם את הטבלה השבורה של השוואת התקנים.

Additional Environmental Conditions in MIL-STD-810

Although Vibration, Shock and Temperature are particularly important considerations in the design of military power supplies, MIL-STD-810 addresses a much broader range of environmental conditions.

Depending on the platform, installation location and equipment life cycle, relevant tests may also include:

• Humidity
• Low Pressure / Altitude
• Rain
• Sand and Dust
• Salt Fog
• Temperature Shock
• Solar Radiation
• Immersion

Not every power supply needs to undergo all of these tests.

This is one of the fundamental principles of MIL-STD-810: test conditions should be tailored to the environmental conditions that the equipment is actually expected to encounter.

For example, a power supply installed inside a protected electronics compartment of a ground vehicle may experience a completely different environment from a power supply installed in an exposed location on a naval platform.

Therefore, the right question is not:

“Is the power supply MIL-STD-810 compliant?”

but rather:

“Which MIL-STD-810 requirements, Methods, Procedures and test conditions was the power supply tested against?”

MIL-STD-810 Does Not Replace MIL-STD-1275, MIL-STD-704 or MIL-STD-461

In this series of articles, we discuss several MIL-STD standards relevant to military power supplies and DC-DC converters.

It is important to understand that these standards do not compete with one another.

Each addresses a different aspect of the operating environment.

Standard	What Does It Address in Relation to the Power Supply?
MIL-STD-1275	Characteristics of 28VDC electrical systems in military vehicles and the electrical events to which connected equipment may be exposed
MIL-STD-704	Characteristics of aircraft electrical power systems and the requirements relevant to connected equipment
MIL-STD-461	EMI/EMC requirements for equipment and subsystems
MIL-STD-810	Environmental conditions and effects such as Vibration, Shock, Temperature and other physical environments

In simple terms:

MIL-STD-1275 and MIL-STD-704 address the electrical power environment.

MIL-STD-461 addresses the electromagnetic environment.

MIL-STD-810 addresses the physical and environmental conditions.

In a real military system, a power supply may need to withstand several of these environments simultaneously.

For example, a DC-DC converter installed in a military vehicle may need to withstand transients on the 28VDC power line according to the applicable MIL-STD-1275 requirements, meet relevant MIL-STD-461 EMI/EMC requirements, and at the same time operate under vibration and temperature profiles established in accordance with MIL-STD-810.

Therefore, it is not necessarily a matter of choosing one standard over another.

In many applications, several standards apply together.

MIL-STD-810 Compliance – What Should You Ask the Manufacturer?

A general statement such as:

Designed to Meet MIL-STD-810

or:

MIL-STD-810 Compliant

can be a useful starting point, but for a serious military application, additional information should be obtained.

It is recommended to verify:

• Which revision of MIL-STD-810 applies
• Which Methods were tested
• Which Procedures were performed
• The test conditions and severity levels
• Whether testing was performed on a representative product
• The mounting configuration used during testing
• Whether the product was operating during the test
• The acceptance criteria
• Whether a Qualification Test Report or other test documentation is available

The distinction between Designed to Meet, Tested to, and compliance with the defined requirements of a specific program can be significant.

Therefore, a logo, product-page headline or general reference to MIL-STD-810 should not be considered sufficient on its own.

Checklist for Selecting a Power Supply for MIL-STD-810 Requirements

When MIL-STD-810 appears in the system requirements, it is best to start with the application rather than the datasheet.

What Is the Platform?

First, determine where the power supply will be installed:

• Military vehicle
• Aircraft
• UAV
• Naval system
• Mobile system
• Fixed ground system
• Other platform

The platform directly affects the environmental conditions the equipment is expected to experience.

What Is the Vibration Profile?

Determine the type, severity and duration of the expected vibration and whether a specific test requirement has been defined.

Do not assume that every Vibration test performed according to MIL-STD-810 represents the same operating environment.

What Are the Shock Requirements?

The relevant Shock events and required test levels should be defined.

It is also important to understand how the power supply is mounted during testing and how it will be mounted in the final system.

What Are the Temperature Ranges?

It is important to distinguish between:

• Operating Temperature
• Storage Temperature
• Start-Up Temperature
• Ambient Temperature
• Baseplate Temperature

These values do not necessarily describe the same operating condition.

How Is the Power Supply Cooled?

Determine whether the product relies on:

• Natural Convection
• Forced Air
• Conduction Cooling
• Cold Plate
• A combination of cooling methods

For a Conduction-Cooled power supply, the Baseplate requirements and mounting interface should be carefully reviewed.

Is Derating Required?

Check whether full output power is available throughout the specified temperature range.

If a Derating Curve is provided, evaluate the actual system operating point rather than relying only on the nominal power rating in the product name.

What Is the Efficiency at the Actual Operating Point?

Higher efficiency generally means less heat that must be dissipated.

Efficiency should be evaluated at the input voltage, output voltage and load relevant to the actual application rather than relying solely on a Peak Efficiency figure.

How Is the Power Supply Mounted?

Check:

• Mounting points
• Tightening torque, where applicable
• Contact surface
• Thermal Interface Material, if required
• Mounting orientation
• Chassis or Cold Plate requirements

Proper installation is part of both the mechanical and thermal design of the system.

A Military Power Supply Is an Electro-Mechanical-Thermal System

When evaluating a power supply on a laboratory bench, it is easy to think of it simply as a box with an input and an output:

Vin → Power Supply → Vout

In a military system, however, the picture is much broader.

The power supply receives energy from an electrical system that may be far from ideal, generates electromagnetic emissions while also needing immunity to external interference, produces heat, and is installed on a platform that vibrates, experiences shock and operates across a wide range of environmental conditions.

A proper design must therefore consider:

Electrical + EMC + Mechanical + Thermal + Environmental

MIL-STD-810 addresses the environmental part of this picture, but its requirements also directly influence how the power supply is designed and integrated into the overall system.

Frequently Asked Questions – MIL-STD-810 and Military Power Supplies

What Is MIL-STD-810?

MIL-STD-810 is a U.S. Department of Defense standard that provides processes and test methods for evaluating the effects of environmental conditions on equipment throughout its life cycle.

It includes methods addressing temperature, vibration, shock, humidity, altitude, sand and dust, and many other environmental conditions.

Is MIL-STD-810 Specifically a Power Supply Standard?

No.

The standard applies to a wide range of equipment and systems.

For power supplies and DC-DC converters, requirements such as Vibration, Shock and Temperature are particularly important because of the interaction between electronic components, power components, mechanical construction and heat dissipation.

Does a Product Marked MIL-STD-810 Compliant Pass Every Test in the Standard?

Not necessarily.

MIL-STD-810 contains numerous Methods and Procedures, and testing is intended to be tailored to the environmental conditions and life cycle relevant to the product.

It is therefore important to determine which tests were actually performed and under what conditions.

What Is the Difference Between Vibration and Shock?

Vibration generally describes continuous or repetitive mechanical motion over time.

Shock is typically a short-duration event involving rapid changes and high acceleration.

Both can affect PCBs, components, solder joints, connectors and mounting points, but the loading and failure mechanisms can be different.

What Is Conduction Cooling?

Conduction Cooling is a method of heat dissipation in which heat is transferred from the power components through the mechanical structure of the product to a Baseplate, Chassis or Cold Plate.

It is commonly used in systems where relying on airflow or an internal fan is impractical or undesirable.

What Is Baseplate Temperature?

Baseplate Temperature is the temperature measured at the specified reference point on the base of the product used for heat transfer.

In Conduction-Cooled power supplies, this parameter can be more important than the temperature of the air surrounding the unit.

What Is Thermal Derating?

Thermal Derating is the reduction of allowable output power when temperature rises above a specified level.

For example, a 500W power supply may be capable of delivering full power up to a specified Baseplate Temperature, after which the allowable load must be gradually reduced.

Does Efficiency Affect High-Temperature Operation?

Yes.

The higher the efficiency, the smaller the proportion of input energy converted into heat inside the power supply.

Reducing power losses decreases the thermal load on the cooling system and can help maintain lower component temperatures.

Does MIL-STD-810 Replace MIL-STD-1275?

No.

MIL-STD-1275 addresses the characteristics of 28VDC electrical power systems in military vehicles, while MIL-STD-810 addresses environmental conditions.

For a military vehicle application, both standards may be relevant to the same power supply.

Does MIL-STD-810 Replace MIL-STD-704?

No.

MIL-STD-704 addresses the characteristics of aircraft electrical power systems.

MIL-STD-810 addresses environmental conditions and environmental testing relevant to the equipment.

For airborne equipment, both may form part of the system requirements.

Does MIL-STD-810 Replace MIL-STD-461?

No.

MIL-STD-461 addresses EMI and EMC requirements for equipment and subsystems.

MIL-STD-810 focuses on environmental conditions such as Vibration, Shock and Temperature.

A military power supply may need to meet requirements from both standards.

Key Terms

MIL-STD-810
A U.S. military standard providing processes and test methods for evaluating the effects of environmental conditions on equipment.

Environmental Tailoring
The process of tailoring environmental conditions and test profiles to the actual application and expected life cycle of the equipment.

Vibration
Continuous or repetitive mechanical motion that can cause mechanical loads, resonance and fatigue.

Shock
A short-duration mechanical event that can impose high acceleration and forces on equipment.

Resonance
A condition in which external excitation approaches a natural frequency of a structure or component, potentially causing significant amplification of local motion.

Conduction Cooling
Heat dissipation through conduction from power components into a mechanical structure, Baseplate, Chassis or Cold Plate.

Baseplate
The base surface of a product used for mechanical mounting and, in some products, as a primary thermal interface for heat transfer.

Cold Plate
A surface designed to receive heat from equipment and transfer it into the cooling system.

Thermal Interface Material – TIM
A material placed between two surfaces to improve thermal contact and reduce thermal resistance at the interface.

Derating
A reduction in allowable power or another operating parameter as operating conditions become more demanding, such as at elevated temperatures.

Operating Temperature
The temperature range over which the product is designed to operate under the conditions specified by the manufacturer.

Storage Temperature
The temperature range over which the product can be stored while not operating.

Qualification Test
A test performed to demonstrate that a product or design meets defined requirements under specified test conditions.

Summary

MIL-STD-810 adds an important dimension to the selection of power supplies and DC-DC converters for military systems.

It is not enough for a power supply to provide the required voltage and output power.

It must also be suitable for the environment in which it will actually operate.

Vibration can impose repetitive loads on components and solder joints. Shock can create high instantaneous forces. Extreme temperatures affect performance and reliability, while the heat generated by the power supply itself must have an effective path out of the unit.

In Conduction-Cooled products, mechanical and thermal design meet at exactly the same point: the Baseplate and its interface with the system.

Therefore, when MIL-STD-810 appears in the project requirements, it is not advisable to rely solely on a general compliance statement.

The platform, operating environment, relevant test methods, mounting configuration and cooling conditions should all be understood.

Ultimately, a military power supply is not simply an electrical component.

It is part of a system in which Electrical, EMC, Mechanical, Thermal and Environmental Requirements must work together.