A vibration rating indicates the level of mechanical vibration that electrical or electronic equipment is designed or tested to withstand under specified conditions.

In industrial power supplies, vibration resistance is commonly expressed using acceleration values such as 3G, 5G or 10G, together with a test frequency range and other operating conditions.

Vibration ratings help engineers determine whether equipment is suitable for applications involving machinery, motors, transportation systems or other environments where continuous or intermittent mechanical vibration may occur.

However, a vibration rating must be interpreted alongside the relevant testing standard, frequency range, duration and mounting conditions. A value such as 3G does not, by itself, fully describe a product's vibration resistance.

What Does G Mean in a Vibration Rating?

In vibration testing, G refers to acceleration expressed as a multiple of standard gravitational acceleration.

One G is approximately equal to 9.81 metres per second squared (m/s²).

For example:

A 3G vibration rating therefore corresponds to an acceleration magnitude three times standard gravitational acceleration.

In sinusoidal vibration testing, this value commonly represents the peak acceleration applied during the specified test.

It does not mean the equipment continuously experiences a force equal to three times its weight, nor does it describe the complete vibration environment.

The actual mechanical stress depends on vibration frequency, displacement, mounting arrangement and the equipment's structural characteristics.

How Is Vibration Resistance Measured?

Vibration testing uses specialised equipment to apply controlled mechanical movement to a product.

The equipment is typically mounted to a vibration test system, often called a shaker, which produces vibration according to a defined test profile.

During testing, engineers may monitor the equipment's operation, structural integrity and electrical performance.

The main test parameters include:

Vibration Frequency

Frequency describes how many vibration cycles occur per second and is measured in hertz (Hz).

For example, a vibration test may specify a frequency range of 10Hz to 500Hz.

Different frequencies can affect equipment differently, particularly when they approach the natural resonant frequencies of mechanical components.

Acceleration

Acceleration describes how rapidly the vibration velocity changes.

It is commonly expressed in G or m/s².

Higher acceleration values generally indicate more severe vibration conditions when other test parameters are comparable.

Displacement

Displacement describes the distance an object moves from its reference position during vibration.

It is commonly expressed in millimetres.

In sinusoidal vibration testing, displacement and acceleration are related through vibration frequency.

Test Duration

Test duration specifies how long the equipment is exposed to vibration.

A product may be tested for a defined period along each axis or through a specified number of frequency sweeps.

Test Direction

Vibration may be applied along three perpendicular axes, commonly identified as X, Y and Z.

Testing multiple axes helps evaluate how the equipment responds to vibration in different directions.

What Does a 3G Vibration Rating Mean?

A 3G vibration rating indicates that equipment has been specified or tested to withstand vibration acceleration of three times standard gravitational acceleration under defined conditions.

For example, an industrial power supply datasheet may specify:

Vibration: 10–500Hz, 3G, 10 minutes/cycle, 60 minutes each along X, Y and Z axes.

This describes a sinusoidal vibration test involving:

• A frequency range from 10Hz to 500Hz

• A specified acceleration level of 3G

• A defined frequency sweep cycle

• Testing along three perpendicular axes

• A specified duration for each axis

The exact interpretation must follow the manufacturer's test specification, including any displacement-controlled portions of the test.

A 3G rating does not necessarily mean the equipment can withstand every vibration environment with acceleration below 3G.

The operating frequency, resonance characteristics, mounting method and duration must also be considered.

3G vs 5G vs 10G Vibration Ratings

Different vibration ratings are used to describe equipment designed for different mechanical environments.

A higher G rating indicates a higher specified acceleration level, but it does not automatically mean a product is more durable in every application.

For example, a power supply tested at 5G over one frequency range cannot necessarily be considered more vibration-resistant than a product tested at 3G over a different range or duration.

Meaningful comparisons require equivalent test conditions.

The test standard, frequency range, acceleration profile, duration and mounting arrangement should all be reviewed.

Why Vibration Frequency Matters

Vibration frequency has a significant influence on the mechanical stress experienced by electronic equipment.

At lower frequencies, vibration may involve relatively large physical movement.

At higher frequencies, displacement may be smaller while acceleration remains substantial.

For sinusoidal vibration, peak acceleration is related to peak displacement and frequency by:

Where:

• a = Peak acceleration in m/s²

• f = Vibration frequency in Hz

• d = Peak displacement in metres

This relationship demonstrates why vibration acceleration cannot be evaluated independently of frequency and displacement.

Mechanical Resonance

Mechanical components have natural frequencies at which they tend to vibrate more strongly.

When an external vibration frequency approaches a component's natural frequency, resonance may amplify its movement and mechanical stress.

In electronic equipment, resonance can affect:

• PCB assemblies

• Transformers and inductors

• Connectors

• Mounting brackets

• Heat sinks

• Internal wiring

Vibration testing helps identify potential weaknesses associated with these conditions.

IEC 60068-2-6 Vibration Testing

IEC 60068-2-6 is an international standard that specifies methods for testing equipment under sinusoidal vibration.

It forms part of the IEC 60068 series of environmental testing standards.

The standard provides procedures for evaluating how products respond to vibration at specified frequencies, amplitudes and durations.

Testing may be used to identify mechanical weaknesses, deterioration in performance or structural damage.

What Does IEC 60068-2-6 Cover?

The standard addresses aspects of sinusoidal vibration testing, including:

• Test equipment and mounting arrangements

• Frequency ranges

• Vibration amplitude

• Frequency sweeping

• Test duration

• Testing along different axes

• Examination of equipment before and after testing

IEC 60068-2-6 does not assign a universal 3G, 5G or 10G pass rating to all equipment.

Instead, the applicable product specification defines the test severity and acceptance criteria.

A manufacturer's claim of compliance should therefore be considered alongside the stated test conditions.

Sinusoidal vs Random Vibration Testing

Not all mechanical vibration follows a regular repeating pattern.

Two common vibration testing methods are sinusoidal and random vibration testing.

Sinusoidal Vibration

Sinusoidal vibration follows a repeating waveform at a defined frequency.

During testing, the frequency may be swept through a specified range to evaluate equipment behaviour and identify resonances.

Sinusoidal vibration is commonly associated with IEC 60068-2-6.

Random Vibration

Random vibration contains a range of frequencies occurring simultaneously with varying amplitudes.

It can better represent certain real-world environments, such as road transportation and complex machinery vibration.

Random vibration tests are commonly specified using acceleration spectral density and overall RMS acceleration, often expressed as Grms.

IEC 60068-2-64 provides methods for broadband random vibration testing.

A 3G peak sinusoidal rating should not be directly compared with a 3Grms random vibration rating, because the test profiles and measurement methods differ.

Vibration Rating vs Shock Rating

Vibration resistance and mechanical shock resistance are related but different characteristics.

Vibration involves repeated or continuous mechanical movement over a period of time.

Mechanical shock involves a relatively sudden acceleration event, often lasting only a short duration.

A product with a high vibration rating does not automatically have an equivalent mechanical shock rating.

Both specifications may be important when selecting equipment for demanding environments.

Vibration Resistance in Power Supplies

Industrial power supplies often contain components that can be affected by mechanical vibration.

These include transformers, capacitors, inductors, semiconductor devices, connectors and printed circuit boards.

Repeated vibration can place stress on solder joints, component leads and mounting structures.

If the equipment is not designed for the intended environment, prolonged exposure may contribute to mechanical fatigue or electrical connection failures.

Power supply manufacturers may improve vibration resistance through:

• Secure component mounting

• Reinforced PCB construction

• Mechanical supports for larger components

• Suitable enclosure designs

• Secure terminal connections

• Potting or encapsulation

• Appropriate mounting arrangements

The effectiveness of these measures depends on the equipment design and vibration conditions.

Vibration Ratings in DIN Rail Power Supplies

DIN rail power supplies are commonly installed inside industrial control cabinets.

These cabinets may be mounted on machinery or positioned near equipment that generates vibration.

For example, manufacturing machinery, compressors, pumps and motor-driven systems can transmit mechanical vibration through surrounding structures.

When selecting a DIN rail power supply, engineers should consider both the manufacturer's vibration rating and the mechanical security of the installation.

Important considerations include:

• DIN rail mounting stability

• Suitable rail and enclosure construction

• Secure electrical connections

• Equipment orientation

• Cable strain relief

• Vibration frequency and severity

• Manufacturer installation requirements

Even where a power supply has been tested to a specified vibration level, the complete installation must be suitable for the operating environment.

Vibration Ratings in Rugged Power Supplies

Rugged power supplies are designed for applications involving demanding environmental or mechanical conditions.

These may include industrial machinery, mobile equipment, transportation systems and outdoor installations.

Some rugged power supplies use fully potted construction, where electronic components are encapsulated within a protective material.

Potting can help support components and reduce movement caused by vibration.

However, the effectiveness depends on the encapsulation material, mechanical design and thermal requirements.

A rugged enclosure or potted construction does not automatically establish a particular vibration rating.

The manufacturer's published test specifications should be used to determine suitability.

How to Select a Power Supply Based on Vibration Rating

When selecting a power supply for a vibration-prone environment, engineers should evaluate more than the G rating alone.

Identify the Operating Environment

Determine whether the equipment will experience continuous vibration, intermittent vibration, mechanical shock or a combination of these conditions.

Review the Frequency Range

Compare the expected vibration frequencies with those covered by the manufacturer's test specification.

Check the Acceleration Rating

Confirm whether the stated acceleration is expressed as peak G, RMS acceleration or another measurement.

Verify the Test Standard

Check whether the product has been tested according to IEC 60068-2-6 or another relevant standard.

Review Mounting Requirements

The mounting method used during testing may affect the equipment's vibration performance.

Installation should follow the manufacturer's recommendations.

Consider Long-Term Reliability

Continuous vibration can contribute to fatigue and deterioration over time.

Equipment should be selected with appropriate consideration of the expected service life and operating conditions.

Evaluate Other Environmental Requirements

Vibration resistance should be considered alongside operating temperature, humidity, ingress protection and electrical performance.

Why Vibration Ratings Matter in Industrial Electronics

Mechanical vibration can affect the reliability of electrical equipment, particularly where components are exposed to repeated movement or resonance.

A suitable vibration rating helps engineers assess whether a power supply or electronic device has been tested under conditions relevant to its intended application.

However, values such as 3G, 5G and 10G should never be considered in isolation.

The complete vibration specification, including frequency, acceleration, duration, test method and mounting arrangement, provides a more meaningful indication of equipment suitability.

For industrial power supplies, DIN rail equipment and rugged electronic systems, understanding vibration ratings supports more reliable product selection and long-term operation.