Expert 2025 Guide: 5 Steps to Select the Right TRACO POWER Power Supply for Your Industry

Abstract

The selection of an appropriate power supply unit represents a foundational decision in the design and maintenance of reliable electronic and industrial systems. An inadequately specified power supply can precipitate system instability, premature failure, and significant operational downtime, leading to cascading financial and safety implications. This guide examines the multifaceted process of choosing a TRACO POWER power supply, a brand recognized for its high-reliability solutions in demanding sectors. It provides a structured, five-step methodology that moves from the initial assessment of electrical load characteristics to the nuanced evaluation of environmental stressors, regulatory compliance, and long-term reliability metrics. By contextualizing these technical considerations within real-world applications—such as industrial control instruments, hydraulic components, and medical analyzers—this document aims to equip engineers, technicians, and procurement specialists with the requisite knowledge to make an informed decision. The objective is to foster a deeper understanding of how a power supply functions not merely as a component, but as a linchpin for overall system integrity and performance.

Key Takeaways

• Begin by precisely calculating your total voltage, current, and power needs.
• Evaluate the operational environment for temperature, vibration, and contaminants.
• Verify that the power supply meets all required international and regional safety certifications.
• Assess reliability metrics like MTBF and consider the total cost of ownership.
• Choose the correct TRACO POWER Power Supply series based on your specific application.
• Plan for future system growth by selecting a unit with a 20-30% power overhead.
• Consult with a trusted supplier for expert guidance on complex requirements.

Table of Contents

• Step 1: Comprehending Your Application’s Power Requirements
• Step 2: Evaluating the Operational Environment and Its Demands
• Step 3: Navigating Safety Standards and Regulatory Compliance
• Step 4: Assessing Reliability, Longevity, and Total Cost of Ownership
• Step 5: Selecting the Optimal TRACO POWER Series for Your Needs
• Frequently Asked Questions (FAQ)
• Conclusion
• References

Step 1: Comprehending Your Application’s Power Requirements

The journey towards selecting the ideal power supply begins not with a catalog of products, but with a deep and introspective look at the system it is destined to animate. To treat the power supply as an afterthought is to build a house upon sand. Its selection is the foundational act of electronic system design. Consider the power supply as the heart of your operation; if the heart is weak or ill-suited to the body’s demands, the entire system is compromised, regardless of the sophistication of its other parts. The first step, therefore, is a meticulous audit of your application’s specific energy appetite. This involves more than just a cursory glance at a nameplate rating; it requires a granular understanding of the load’s behavior under all operating conditions. We must move beyond static numbers and embrace the dynamic reality of power consumption.

Defining the Electrical Load: Voltage, Current, and Power

At its most fundamental level, defining the electrical load is an exercise in quantifying three interconnected parameters: voltage (V), current (A), and power (W). It can be helpful to visualize these concepts using a hydraulic analogy. Voltage is akin to the water pressure in a pipe—the potential force driving the flow. Current is analogous to the flow rate itself—the volume of water moving through thepipe at any given moment. Power, measured in watts, is the product of these two (P = V × I), representing the total work the water can perform, such as turning a water wheel.

Your first task is to determine the required DC output voltage for your load. Is it 5V for digital logic, 12V for motors and relays, 24V for industrial sensors and PLCs, or 48V for telecommunications equipment? This is typically a fixed requirement dictated by the components in your system. Getting this wrong can be immediately destructive, so it’s a non-negotiable starting point.

Next, you must calculate the total current your system will draw. This is rarely a single number. You must sum the current requirements of every single component that the power supply will energize. This includes microcontrollers, sensors, actuators, indicators, and communication modules. For instance, an industrial control instrument may have a main processor drawing 200mA, a display drawing 150mA, several sensors drawing 50mA each, and a communication radio that draws 300mA during transmission. You must add all these up to find the total continuous current draw. Let’s imagine a simple system:

• PLC Controller: 24V, 0.5A
• HMI Display: 24V, 0.8A
• Three Proximity Sensors: 24V, 0.1A each (0.3A total)
• Ethernet Switch: 24V, 0.4A

The total continuous current draw would be 0.5 + 0.8 + 0.3 + 0.4 = 2.0A. The total power required is then 24V × 2.0A = 48W. A common mistake is to select a 48W power supply based on this calculation. However, this leaves no margin for error, component aging, or future expansion. A prudent design philosophy, one that we will explore further, dictates adding a safety margin of at least 20-30%. In this case, a 60W or even a 75W unit would be a much more robust choice. This oversizing provides headroom, reduces stress on the power supply’s components, and allows it to run cooler, thereby extending its operational life.

Accounting for Inrush Current and Peak Loads in Dynamic Systems

Static calculations provide a baseline, but few real-world systems exhibit a perfectly constant load. Many devices draw a large, momentary surge of current when first powered on. This is known as inrush current. Think of it as the initial effort required to get a heavy flywheel spinning; once it’s moving, it requires far less energy to maintain its speed. This phenomenon is particularly prevalent in systems with large capacitive loads or inductive components like motors, which are common in applications involving an air compressor or hydraulic component.

For example, the capacitors on the input of multiple downstream DC/DC converters will all try to charge simultaneously, creating a massive, short-lived current demand on the main AC/DC power supply. Similarly, starting a motor in an air compressor accessory can draw a current several times its nominal running current for a few hundred milliseconds. If the chosen TRACO POWER Power Supply does not have the capability to handle this peak, its overcurrent protection circuit might trip, preventing the system from starting, or in a worst-case scenario, the supply could be damaged.

How do you account for this? First, consult the datasheets of the components in your system. Manufacturers often specify the peak inrush current and its duration. Second, review the power supply’s datasheet for its peak load capability. Many TRACO POWER units are explicitly designed to handle peak loads. For example, a power supply might be rated for 150W continuously but capable of delivering 200W for up to 5 seconds. This feature is invaluable for applications with periodic high-power demands, as it allows you to size the power supply for the average load rather than the peak, saving cost and space. If the datasheet is unclear, a good rule of thumb is to measure the inrush current with an oscilloscope and a current probe. This empirical data is the most reliable guide. A failure to consider inrush current is one of the most common reasons for mysterious start-up failures in complex systems.

Analyzing the Power Needs of Specific Equipment

The theoretical understanding of power requirements must be grounded in the practical realities of the equipment you intend to use. The power profile of a sensitive laboratory analyzer is vastly different from that of a rugged hydraulic valve controller.

An analyseur, whether for medical diagnostics or industrial process control, often requires exceptionally clean and stable power. Electrical noise, ripple, or voltage fluctuations from the power supply can directly impact the sensitive analog measurement circuits, leading to inaccurate readings or a poor signal-to-noise ratio. For such applications, the power supply’s output ripple and noise specification becomes a paramount concern. You should seek out models with specifications in the low millivolt range. Furthermore, medical analyzers require power supplies that meet stringent safety standards, such as IEC 60601-1, which we will discuss in Step 3.

In contrast, a composant hydraulique, such as a solenoid-operated valve core, presents a different challenge. The load is primarily inductive. When the solenoid is energized, it creates a brief inrush current. More significantly, when the solenoid is de-energized, the collapsing magnetic field can generate a large reverse voltage spike (known as back EMF). A robust power supply must be able to withstand this without damage. The power demand is often intermittent and dynamic, requiring a supply that can respond quickly to load changes.

Industrial control instruments, like PLCs and distributed I/O modules, typically require a standard 24VDC. While the individual components are low power, a large control cabinet can contain dozens of such modules, leading to a substantial overall load. Here, the key challenges are power density (fitting enough power into a crowded DIN rail) and reliability. The failure of a single power supply can bring an entire production line to a halt, making reliability the most sought-after attribute. This is where DIN-rail mounted power supplies, like those in the TRACO POWER TBL or TIB series, excel.

Finally, consider accessoires pour compresseurs d'air. These might include electronic controllers, sensors, and cooling fans. The primary load is often the fan motor, which has its own inrush current characteristics. The environment is often hot, oily, and subject to vibration, placing significant stress on the power supply. A supply for this application must be chosen with a high operating temperature rating and a rugged mechanical design.

Future-Proofing: Planning for System Expansion

A system is rarely static. Over its lifespan, new features are added, sensors are upgraded, and capabilities are expanded. The power supply you choose today must be able to accommodate the needs of tomorrow. A system designer who selects a power supply that is running at 95% of its rated capacity on day one is creating a future maintenance problem.

A widely accepted best practice is to size your power supply to operate at approximately 70-80% of its maximum rated load under normal conditions. This 20-30% headroom serves several purposes. Firstly, it provides the capacity for future system upgrades. If you need to add another sensor or a more powerful processor, you can do so without needing to replace the entire power supply. Secondly, operating a power supply well below its maximum rating reduces thermal stress on its internal components, particularly electrolytic capacitors. Heat is the primary enemy of component longevity. A cooler-running power supply will have a significantly longer operational life and a better Mean Time Between Failures (MTBF). This practice of derating for load is a cornerstone of reliable system design. It transforms the power supply from a consumable component into a long-term asset. It is an investment in future stability.

Step 2: Evaluating the Operational Environment and Its Demands

Once you have a firm grasp of your system’s electrical appetite, the next critical step is to turn your attention outward, to the world in which your device will live and operate. A power supply that performs flawlessly on a climate-controlled laboratory bench may fail catastrophically in the heat of a Middle Eastern desert, the vibrating chassis of a mining vehicle, or the humid atmosphere of a Southeast Asian factory. The environment is an active participant in the life of your system, and its demands are non-negotiable. TRACO POWER has built its reputation on creating products that thrive in these challenging conditions, but selecting the right one requires a careful and honest assessment of the operational environment.

Temperature Extremes: Convection vs. Forced Air Cooling

Temperature is arguably the most significant environmental factor affecting power supply reliability and lifespan. Every electronic component has a maximum operating temperature, and the electrolytic capacitors used in most power supplies are particularly sensitive. A general rule of thumb, known as the Arrhenius equation, suggests that for every 10°C increase in operating temperature, the life of an electrolytic capacitor is halved. This makes thermal management a primary design consideration.

You must examine the power supply’s datasheet for its operating temperature range and, more importantly, its derating curve. A derating curve shows how the maximum output power of the supply must be reduced as the ambient temperature increases. For example, a 100W power supply might be able to deliver its full power up to 50°C, but beyond that, you may need to derate its output by 2.5% per degree Celsius. At 70°C, it might only be able to safely provide 50W. Ignoring this curve is a recipe for failure. You must consider the worst-case ambient temperature inside your enclosure, not just the outside air temperature.

The method of cooling is intrinsically linked to temperature.

• Convection-cooled power supplies are designed to dissipate heat naturally through airflow. They require adequate ventilation and proper orientation (as specified in the installation manual) to allow hot air to rise and be replaced by cooler air. They are silent and reliable as they have no moving parts.
• Forced air-cooled power supplies use a fan to actively move air across heat-generating components. This allows for much higher power density (more watts per cubic inch), but introduces a potential point of failure: the fan itself. In dusty or dirty environments, fans can become clogged and fail, leading to rapid overheating of the power supply.
• Conduction-cooled or baseplate-cooled power supplies are designed to be mounted onto a metal chassis or heatsink, transferring their heat directly into the larger thermal mass. These are common in sealed enclosures where airflow is not possible.

Your choice depends on your application. For a silent medical analyzer in a clean hospital room, a convection-cooled unit might be perfect. For a compact, power-hungry industrial control system, a fan-cooled unit might be necessary, but it will require a maintenance schedule to check the fan. For a sealed NEMA enclosure on an outdoor oil rig, a conduction-cooled supply is the only viable option.

Shock, Vibration, and Mechanical Stress in Heavy Industry

Many industrial environments are far from gentle. Equipment installed on or near stamping presses, conveyor systems, mining vehicles, or railway applications is subjected to constant shock and vibration. These mechanical forces can be insidious, slowly causing component leads to fracture, solder joints to crack, and large components like transformers and capacitors to break free from the PCB.

When selecting a TRACO POWER Power Supply for such an environment, you must look for features that indicate mechanical robustness. The datasheet should specify the product’s tolerance to shock and vibration, often tested according to standards like IEC 60068-2-27 (for shock) and IEC 60068-2-6 (for vibration).

What makes a power supply rugged?

1. Potting or Encapsulation: Many TRACO POWER DC/DC converters and some AC/DC modules are fully potted with a thermally conductive epoxy. This material surrounds all the components, holding them in place and protecting them from vibration. It also helps with heat dissipation and provides protection against moisture and dust.
2. Conformal Coating: For PCB-based power supplies, a thin layer of acrylic or silicone conformal coating can be applied. This coating protects the board and solder joints from humidity and corrosive agents, while also providing some damping against vibration.
3. Robust Mechanical Design: Look for features like screw terminals instead of push-in connectors, secure mounting points, and a sturdy metal case. The weight and mounting of large magnetic components should be reinforced to prevent them from acting like levers under vibration.

Imagine you are designing the control system for a rock crusher. The constant, low-frequency, high-amplitude vibration would quickly destroy a standard power supply. You would need to select a fully potted or heavily ruggedized model, perhaps mounting it with vibration-damping hardware, to ensure the system survives its first day of operation.

Dealing with Humidity, Dust, and Chemical Exposure

The air in many industrial settings is not just air. In a textile mill, it might be filled with conductive lint. In a food processing plant, it might be subject to high-pressure washdowns with caustic cleaning agents. In a coastal or marine application, it will be laden with corrosive salt spray. In a desert environment, fine dust can infiltrate every crevice. Each of these contaminants poses a threat to a power supply.

• Humidity and Condensation: High humidity can lead to condensation on the PCB, reducing insulation distances and potentially causing short circuits. Conformal coating is an effective defense against this.
• Dust: Conductive dust can cause shorts, while even non-conductive dust can blanket components, acting as a thermal insulator and causing them to overheat. Fan-cooled power supplies are particularly vulnerable here. A sealed or potted unit, or one placed inside a properly filtered enclosure, is a better choice.
• Chemicals: Corrosive vapors or direct splashes of chemicals can eat away at component leads, connectors, and PCB traces. Again, conformal coating and encapsulation provide a strong barrier. The case material itself is also a factor; a rugged aluminum or stainless steel case will fare better than a simple plastic one.

The IP (Ingress Protection) rating system is a useful guide here. An IP rating consists of two digits. The first digit indicates protection against solid objects (like dust), and the second indicates protection against liquids (like water). For example, a power supply with an IP67 rating is completely dust-tight and can be submerged in water up to 1 meter deep for 30 minutes. While you may not need to submerge your power supply, an IP67 rating gives you confidence that it will withstand dust and high-pressure washdowns.

Altitude Considerations and Their Impact on Power Supply Performance

A less commonly considered but equally important environmental factor is altitude. As altitude increases, air density decreases. This has two major consequences for a power supply.

Firstly, the cooling efficiency is reduced. Since there are fewer air molecules to carry heat away, both convection-cooled and fan-cooled power supplies will run hotter at high altitudes. Most manufacturers require you to derate the maximum output power of the supply when operating above a certain altitude, typically 2000 meters (about 6500 feet). The datasheet will provide a specific derating curve, for example, derating by 5% for every 1000 meters above 2000 meters. A system designed for Lima, Peru (at sea level) might fail due to overheating if deployed in La Paz, Bolivia (at 3,640 meters) without proper derating.

Secondly, the lower air density reduces the dielectric strength of the air. Air is a natural insulator, and the spacing between high-voltage traces on a power supply’s PCB is designed with the insulating properties of sea-level air in mind. At high altitudes, the reduced insulation capability increases the risk of arcing between high-voltage components. Safety agencies require larger “creepage and clearance” distances for equipment certified for use above 2000 meters.

When selecting a power supply for a high-altitude application, such as an observatory on a mountaintop or an avionics system, you must consult the datasheet for its maximum operating altitude and any associated derating requirements. Choosing a unit that is already certified for operation at, for instance, 5000 meters, simplifies the design process and ensures safety and reliability. This forethought prevents field failures in locations where service and replacement are exceptionally difficult.

Step 3: Navigating Safety Standards and Regulatory Compliance

Having defined the electrical and environmental context of your application, we must now turn to the legal and regulatory landscape. In our interconnected global economy, products must meet a complex web of safety standards and regulations to be legally sold and operated. These are not arbitrary rules; they are the embodiment of decades of experience in preventing fire, electric shock, and electromagnetic interference. For a component as fundamental as a power supply, compliance is not optional. It is a prerequisite for market access and a cornerstone of user safety and system compatibility. A leading professional dedicated equipment supplier will ensure that the products they offer, like the TRACO POWER Power Supply range, come with the necessary documentation and certifications for your target market.

Understanding Global Certifications: IEC, UL, EN, and CSA

When you examine a TRACO POWER datasheet, you will see a list of logos and standard numbers: UL, CSA, EN, IEC, and others. To the uninitiated, it can look like an alphabet soup. However, each one represents a gateway to a specific market and a guarantee of safety testing. Let’s demystify the main players.

• IEC (International Electrotechnical Commission): This is a global organization that develops and publishes international standards for all electrical, electronic, and related technologies. IEC standards themselves are not laws, but they form the basis for national standards around the world. For example, IEC 62368-1 is the modern, hazard-based safety standard for information and communication technology equipment, which is replacing the older IEC 60950-1.
• EN (European Norm): These are the harmonized standards for the European Union. In most cases, an EN standard is an IEC standard that has been adopted with few or no changes, making it law within the EU. For a product to receive a CE mark and be sold in Europe, it must comply with the relevant EN standards. So, EN 62368-1 is the European version of IEC 62368-1.
• UL (Underwriters Laboratories): This is a key safety organization in the United States. A “UL Listed” mark means the product has been tested by UL and meets their published standards of safety. “UL Recognized” (indicated by a reversed RU symbol) means the component is approved for use within a larger UL-listed system. UL often develops its own standards, but they are increasingly harmonized with IEC standards. For example, UL 62368-1 is the US version of the same core standard.
• CSA (Canadian Standards Association): This is the Canadian equivalent of UL. A product with a CSA mark has been tested and certified for sale in Canada. Due to a mutual recognition agreement, a mark that says “cULus” or similar indicates that the product is certified for both the US and Canadian markets.

Why does this matter for you? If you are building a machine for export to the United States, you must use a power supply with a UL certification. If it’s destined for Germany, it must have a CE mark, which implies compliance with the relevant EN standards. If your market is global, you should choose a power supply that carries a “world-wide” safety approval package, including IEC, EN, and UL/CSA certifications. This saves you the immense cost and time of having to recertify your final product for each individual region. TRACO POWER specializes in providing power supplies with these comprehensive certification packages.

Medical-Grade vs. Industrial-Grade: Deciphering the Nuances

One of the most important distinctions in the world of power supplies is between industrial-grade and medical-grade units. While they may look similar and have similar power ratings, they are designed and tested to vastly different standards. The core difference lies in the level of protection provided to the patient and operator.

The primary standard for medical equipment is IEC 60601-1. This standard is far more stringent than its industrial counterpart (IEC 62368-1). The key differences are:

1. Lower Leakage Currents: All power supplies have some small amount of current that “leaks” from the AC input side to the DC output side, a phenomenon known as leakage current. In industrial equipment, this is not a major concern. However, in medical equipment where a patient may be electrically connected to the device (for example, through ECG sensors), this leakage current could be dangerous. IEC 60601-1 sets extremely low limits for leakage current, often in the microamp range.
2. Increased Isolation (MOPP/MOP): The standard defines Means of Protection (MOP) to prevent dangerous voltages from reaching the patient or operator. It specifies higher levels of electrical isolation (larger creepage and clearance distances and more robust insulation) than industrial standards. It further distinguishes between Means of Operator Protection (MOOP) and the more stringent Means of Patient Protection (MOPP). A power supply rated as “2 x MOPP” provides two independent layers of protection for the patient, making it suitable for direct-contact medical devices. This is a critical requirement for any medical analyzer that has a patient-applied part.
3. Risk Management: Compliance with IEC 60601-1 requires a formal risk management process as defined by ISO 14971. The manufacturer must identify all potential hazards and demonstrate how they have been mitigated in the design.

Using an industrial-grade power supply in a medical device is not just a bad idea; it is illegal in most parts of the world and exposes patients to unacceptable risks. TRACO POWER offers extensive lines of medical-grade power supplies, such as the TPP and THM series, that are fully certified to the latest editions of IEC 60601-1 and carry the 2 x MOPP rating, making them a pre-approved solution for designers of medical equipment.

EMC/EMI Compliance: Minimizing Electromagnetic Interference

Every power supply, by its very nature as a high-frequency switching device, is a potential source of electromagnetic noise. This noise, known as Electromagnetic Interference (EMI), can travel in two ways: it can be conducted back onto the AC power line, or it can be radiated through the air like a tiny radio transmitter.

Why should you care about this? This EMI can interfere with the operation of other nearby electronic devices. Imagine a power supply in an industrial control panel radiating noise that corrupts the data on a nearby communication cable, or conducted noise from the supply interfering with the sensitive measurements of a process analyzer. To prevent this electronic chaos, regulatory bodies have established strict limits on the amount of EMI a product can generate. These are known as Electromagnetic Compatibility (EMC) standards.

The key standards are CISPR 32 / EN 55032 for emissions and EN 55035 / IEC 61000 for immunity.

• Emissions (EN 55032): This standard defines the maximum allowable levels of conducted and radiated noise. There are two main classes: Class A (for industrial environments) and the more stringent Class B (for residential, commercial, and light-industrial environments). A Class B compliant power supply produces less noise and is a safer choice for systems with sensitive analog or RF components.
• Immunity (IEC 61000 series): This set of standards defines how well a power supply must tolerate incoming electrical disturbances, such as electrostatic discharge (ESD), voltage dips, and fast transients on the power line. A power supply with high immunity will continue to operate reliably even on an electrically “dirty” power grid, which is common in heavy industrial facilities.

TRACO POWER power supplies are designed with integrated EMI filters to meet these standards. Choosing a pre-compliant module saves the designer the difficult, expensive, and time-consuming task of designing their own external filtering and getting it certified. It is a classic “build vs. buy” decision where “buy” is almost always the more efficient choice.

Regional Specifics for South America, Russia, and Southeast Asia

While global IEC standards have created a great deal of harmony, regional and national deviations still exist. A savvy designer must be aware of the specific requirements for their target markets.

• South America: Many countries in this region, such as Brazil and Argentina, have their own national certification bodies (INMETRO in Brazil, S-Mark in Argentina) that largely base their requirements on IEC standards. However, they may require in-country testing or representation. It’s also important to check the local mains voltage and frequency, which can vary (e.g., 220V/50Hz in Argentina, but a mix of 127V/220V at 60Hz in Brazil). A power supply with a universal input range (85-264VAC) is highly advantageous.
• Russia (Eurasian Economic Union): Products sold in Russia, Kazakhstan, Belarus, Armenia, and Kyrgyzstan must bear the EAC (Eurasian Conformity) mark. This mark indicates compliance with the technical regulations of the Eurasian Economic Union. For power supplies, this typically involves demonstrating compliance with safety (TR CU 004) and EMC (TR CU 020) regulations, which are themselves harmonized with IEC standards.
• Southeast Asia: This is a diverse region. Countries like Singapore and Malaysia largely accept IEC standards and CE/UL marks. Others, like Indonesia (SNI) or Vietnam (TCVN), have their own national marks that may require additional testing or paperwork. As with South America, checking the local mains voltage and stability is vital. Power grids in some developing areas can be less stable, making a power supply with a wide input range and good immunity to sags and surges a more reliable choice.

By selecting a TRACO POWER Power Supply that already carries a broad range of global and regional certifications, you are not just buying a component; you are buying market access and peace of mind.

Step 4: Assessing Reliability, Longevity, and Total Cost of Ownership

The purchase price of a power supply is merely the visible tip of the iceberg. A truly insightful selection process looks beneath the surface to evaluate the long-term reliability and the total cost of owning, operating, and maintaining the unit over its entire lifecycle. In critical industrial, medical, or infrastructure applications, the cost of a single power supply failure—measured in lost production, emergency maintenance, and potential damage to other equipment—can easily dwarf the initial cost of the unit by orders of magnitude. This is a domain where a higher initial investment in a quality product from a reputable manufacturer like TRACO POWER often yields substantial long-term savings. The pursuit of the lowest price can be a profoundly expensive endeavor.

Mean Time Between Failures (MTBF): A True Measure of Reliability?

Mean Time Between Failures (MTBF) is one of the most common metrics used to quantify reliability. It is expressed in hours and, in theory, represents the average time a population of units will operate before a failure occurs. You will often see impressive figures in datasheets, sometimes numbering in the millions of hours. But what does this number actually mean?

It is vital to understand that MTBF is a statistical prediction, not a guarantee of service life. An MTBF of 1,000,000 hours does not mean your individual power supply will run for 114 years. Instead, it suggests that if you have 1,000 such units running, you can expect, on average, one failure every 1,000 hours.

Furthermore, not all MTBF figures are created equal. They are typically calculated using predictive models, not observed from real-world failures. The most common models are:

• MIL-HDBK-217F: A US military standard that calculates reliability based on the component count, component types, and various stress factors (temperature, environment). It is known for producing relatively conservative (lower) MTBF figures.
• Telcordia SR-332: A standard from the telecommunications industry, often resulting in more optimistic numbers than MIL-HDBK-217F.
• SN 29500: A Siemens standard widely used in industrial applications.

When comparing two power supplies, you must ensure you are comparing MTBF figures calculated using the same standard and under the same baseline conditions (e.g., ambient temperature and load). A higher MTBF is generally better, but it should be treated as a relative indicator of design robustness rather than an absolute promise of longevity. A more practical measure is often the manufacturer’s warranty period and their field-proven failure rate data, if available. TRACO POWER is known for its high-reliability designs, often backed by 3-year or 5-year warranties, which can be a more tangible indicator of quality than a calculated MTBF alone.

The Role of High-Quality Components and Manufacturing Processes

The predicted reliability of a power supply is fundamentally rooted in the quality of the components used and the precision of the manufacturing process. A power supply is only as strong as its weakest link. A low-cost manufacturer might save a few cents by using 85°C-rated electrolytic capacitors instead of 105°C-rated ones, or by using a cheaper control IC with looser tolerances. These small compromises can have a dramatic impact on the unit’s lifespan, especially in a warm industrial environment.

Here are some hallmarks of a high-quality design, which are characteristic of TRACO POWER products:

• High-Temperature, Long-Life Capacitors: The electrolytic capacitors in the input and output filtering stages are often the first components to fail. Using high-grade capacitors rated for 105°C or even 125°C, and from reputable Japanese manufacturers, significantly extends the operational life of the power supply.
• Conservative Design Margins: Quality designs do not run components at their absolute maximum ratings. A well-designed power supply will use a MOSFET rated for 600V where only 400V is expected, or a diode rated for 10A in a 5A circuit. This derating reduces stress and heat, promoting longevity.
• Effective Thermal Management: This includes not just the primary heatsinks, but also the layout of the PCB to ensure that heat-sensitive components are not placed next to heat-generating ones. The use of thermal vias and large copper planes to draw heat away from components is also a sign of a thoughtful design.
• Automated and Inspected Manufacturing: Consistent quality requires a high degree of automation in the manufacturing process, such as automated optical inspection (AOI) to check solder joints and component placement. Rigorous testing at multiple stages, including a “burn-in” test where the finished power supply is run under load at an elevated temperature for several hours, helps to weed out early failures before the product leaves the factory.

When you choose a power supply from a manufacturer known for quality, you are paying for these unseen details—the better capacitors, the design margins, the rigorous testing. This is the foundation of long-term reliability.

Calculating Total Cost of Ownership (TCO) Beyond the Purchase Price

A sophisticated procurement strategy focuses on Total Cost of Ownership (TCO), not just the initial acquisition cost. The TCO provides a more holistic financial picture, encompassing all direct and indirect costs over the product’s life. The formula can be expressed as:

TCO = Initial Cost + (Energy Cost + Maintenance Cost + Downtime Cost) × Lifespan

Let’s break this down in the context of a power supply:

• Initial Cost: The purchase price of the unit. A high-reliability TRACO POWER Power Supply may have a higher initial cost than a generic alternative.
• Energy Cost: This is determined by the power supply’s efficiency. A power supply with 94% efficiency wastes only 6% of the input power as heat. A less efficient 85% unit wastes 15%. Over a 5-year lifespan in a 24/7 application, this difference in wasted energy translates directly into a higher electricity bill. The higher efficiency also means less heat is generated, reducing the load on factory air conditioning systems.
• Maintenance Cost: For a low-quality power supply, this could include the labor cost of diagnosing failures and replacing the unit. For a fan-cooled unit, it includes the cost of periodically inspecting and replacing the fan.
• Downtime Cost: This is often the largest and most significant component of TCO in an industrial setting. What is the cost to your business if a production line is down for four hours while a technician replaces a failed $50 power supply? It could be thousands or tens of thousands of dollars in lost revenue and productivity. If the failure of a power supply in a remote SCADA system for a pipeline requires a helicopter flight for a technician to replace it, the TCO of that cheap power supply becomes astronomical.

When viewed through the lens of TCO, the decision often shifts. A power supply that is 10% more efficient, has double the MTBF, and is backed by a 5-year warranty may have a far lower TCO than its cheaper rival, even if its initial price is 50% higher. This is the economic argument for prioritizing quality and reliability.

Warranty, Support, and the Value of a Reputable Supplier

Finally, consider the ecosystem of support that surrounds the product. A manufacturer’s warranty is a direct statement of its confidence in its own products. A 1-year warranty suggests the manufacturer expects the product to last just beyond that period. A 3-year or 5-year warranty, as is common for many TRACO POWER industrial and medical series, indicates a much higher level of design and manufacturing quality. It is a promise that the manufacturer is willing to stand behind.

Beyond the warranty, the availability of technical support is invaluable. What happens when you have a complex application problem or a field failure you can’t diagnose? Working with a knowledgeable supplier who can provide expert application support is a significant benefit. They can help you interpret datasheets, suggest the right product for a tricky environment, and assist with troubleshooting. This relationship transforms the transaction from a simple purchase into a partnership. When you learn more about our commitment to quality, you will see that providing this level of support is central to our philosophy. It is part of the value proposition that extends far beyond the hardware itself.

Step 5: Selecting the Optimal TRACO POWER Series for Your Needs

With a comprehensive understanding of your electrical, environmental, regulatory, and long-term reliability requirements, you are now equipped for the final step: navigating the TRACO POWER portfolio to pinpoint the ideal product series for your specific application. This is not about finding a single “best” power supply, but about finding the one that represents the optimal intersection of performance, features, and cost for your unique set of constraints. TRACO POWER offers a vast and diverse range of products, and this breadth is a strength, as it ensures a tailored solution is likely available. We can simplify this landscape by grouping products into major families and then applying our knowledge through practical examples.

An Overview of TRACO POWER’s Product Families

TRACO POWER’s portfolio can be broadly categorized by form factor and primary function. Understanding these categories is the first step in narrowing down your search.

• DIN-Rail Power Supplies (TIB, TBL, TCL Series): These are the workhorses of industrial automation and control cabinets. Designed to clip directly onto a standard DIN rail, they offer a secure and space-saving installation method. They are characterized by their rugged metal or plastic cases, excellent thermal performance, and features tailored for industrial environments, such as high immunity to electrical noise and options for parallel operation to increase power or provide redundancy. The TIB series, for example, is known for its high power density and advanced features, while the TBL series offers a cost-effective solution for standard applications.
• Enclosed / Chassis Mount Power Supplies (TXM, TPI, TPP Series): These power supplies are typically housed in a perforated metal case and are designed to be mounted onto the chassis of a larger piece of equipment. They offer a wide range of power levels, from tens of watts to over a thousand watts. This category includes general-purpose industrial series (TPI), high-performance series with excellent EMC characteristics (TXM), and medically certified series (TPP). Their enclosed nature provides a good degree of mechanical protection and EMI shielding.
• DC/DC Converters (TEN, THM, TMR Series): Unlike AC/DC supplies that convert mains AC voltage, DC/DC converters take one DC voltage and convert it to another. They are essential for creating multiple voltage rails within a system from a single primary DC bus. They are also used to provide electrical isolation between different parts of a circuit, breaking ground loops and improving safety. TRACO POWER offers an exceptionally wide range of DC/DC converters, from low-power isolated units in tiny packages (TMR series) to high-power converters for railway applications (TEN series) and medically certified converters with very high isolation (THM series).
• Open-Frame / PCB Mount Power Supplies (TOL, TMLM Series): These supplies are provided as a bare PCB assembly, intended to be integrated directly into the end-user’s equipment. They offer a cost-effective and space-saving solution but require the end-user to provide the enclosure and ensure proper safety isolation and thermal management. They are common in high-volume OEM applications where the power supply is a deeply integrated part of the product.

Understanding these families allows you to make an initial triage. Are you building a control panel? Start with DIN-rail supplies. Are you designing a standalone piece of test equipment? Look at enclosed units. Do you need to create a 5V rail from a 24V bus? You need a DC/DC converter.

Case Study 1: Powering a Remote Industrial Control Instrument

Let’s imagine a scenario. You are an engineer designing a monitoring system for a water pumping station in a rural part of South Africa. The system consists of a PLC, a cellular modem for communication, and several sensors to monitor pressure and flow. The entire system will be housed in a NEMA-rated outdoor enclosure.

Let’s apply our five-step process:

1. Power Requirements: You calculate the total load to be 24VDC at 3A (72W). The cellular modem has a peak transmission current, so you need a supply that can handle short-term peaks. To future-proof, you decide to look for a supply with around 100W of power.
2. Environment: The enclosure will be exposed to summer temperatures that can reach 45°C. There is no active cooling. The location is also subject to occasional electrical storms, so high immunity to power line surges is needed.
3. Regulations: The product will be sold and installed locally in South Africa, which largely follows IEC standards. A CE mark would be sufficient. EMC Class B is preferred to avoid any interference with the radio modem.
4. Reliability: The site is remote. A maintenance visit is expensive. Therefore, high reliability and a long lifespan are paramount. A 5-year warranty would be ideal.
5. Selection: Based on these requirements, a DIN-rail power supply is the natural choice for mounting within the control box. You need a convection-cooled unit that can handle the high ambient temperature. You look at the TRACO POWER DIN-rail portfolio. The TIB 120-124EX series stands out. It is a 120W, 24V model. Its datasheet shows it can deliver full power up to 60°C, providing ample margin for your 45°C requirement. It has a high efficiency of 94%, which minimizes waste heat inside the enclosure. It complies with IEC 61000 for high immunity and meets EMC Class B standards. Crucially, it is part of a series designed for hazardous locations (ATEX/IECEx certified), indicating extreme ruggedness, and comes with a 5-year warranty. It perfectly matches the application’s demands for power, environmental resilience, and long-term reliability.

Case Study 2: Ensuring Uptime for a Medical Analyzer with a Certified Power Supply

Now, consider a different challenge. You are part of a team in Brazil developing a new benchtop blood analyzer for use in hospitals and clinics. The device uses sensitive analog circuitry to perform its measurements.

1. Power Requirements: The system requires a main 12VDC rail for motors and a smaller, isolated 5VDC rail for the digital processing board. The total power is calculated to be 45W. The analog circuits are extremely sensitive to power supply noise.
2. Environment: The device will be used in a clean, climate-controlled laboratory or hospital environment. Low audible noise is important.
3. Regulations: The device is a medical product, so it must comply with IEC 60601-1. Since it will be sold in Brazil, it will also need INMETRO certification, which is based on the IEC standard. The analyzer has probes that may come into contact with patient samples, so a 2 x MOPP rating is required for the power supply to ensure patient safety.
4. Reliability: The accuracy of medical tests depends on the stable operation of the device. A power supply failure could lead to incorrect diagnoses. High reliability is non-negotiable.
5. Selection: You need an enclosed AC/DC power supply for the main 12V rail. The key requirement is medical certification. You search TRACO POWER’s medical portfolio and find the TPP 65 series. The TPP 65-112 is a 65W, 12V model. Its datasheet confirms it is certified to IEC/EN/UL 60601-1 3rd edition and has a 2 x MOPP rating up to 5000m altitude. It boasts a very low leakage current of less than 100µA, protecting the patient. It also has a reinforced insulation system. For the secondary 5V rail, you need an isolated DC/DC converter. The THM series of medical-grade DC/DC converters is the perfect choice. A small, 3W converter like the THM 3-1211 can take the main 12V and create a fully isolated, regulated 5V output, also with a 2 x MOPP rating. By choosing pre-certified medical components from TRACO, you have dramatically simplified the regulatory approval process for your entire device.

Making the Final Selection: A Decision Matrix Approach

For complex projects, a formal decision matrix can be a powerful tool to objectify the selection process. This matrix allows you to score various power supply series against your specific project requirements.

By filling out a matrix like this, you create a clear, documented rationale for your choice. It moves the decision from a gut feeling to a structured, defensible engineering conclusion. After using such a matrix to identify the most suitable series, you can then explore our range of TRACO POWER solutions to find the exact model with the precise voltage and power rating your application demands.

Frequently Asked Questions (FAQ)

What is “derating” and why is it necessary for a power supply?

Derating is the practice of operating a component, like a power supply, at less than its maximum rated capacity to increase its reliability and lifespan. There are two primary types of derating for power supplies: derating for temperature and derating for load. Temperature derating means reducing the maximum output power as the ambient temperature rises, which is necessary to prevent overheating. A derating curve in the datasheet shows how much power the unit can safely deliver at a given temperature. Load derating means choosing a power supply with a higher power rating than your system’s actual load (e.g., using a 100W supply for an 80W load). This reduces stress on internal components, allows the unit to run cooler, and provides capacity for future upgrades.

Can I connect two power supplies in parallel?

You can, but only if the power supply is specifically designed for it. Simply connecting the outputs of two standard power supplies together is not recommended, as small differences in their output voltages will cause one unit to supply all the current while the other does nothing. Power supplies designed for parallel operation have a special “current sharing” or “droop sharing” function. This allows multiple units to actively balance the load between them. This is done for two main reasons: to increase the total available power (e.g., two 10A supplies to get 20A) or to create a redundant system (an N+1 system), where if one power supply fails, the other can take over the full load seamlessly, ensuring continuous operation for critical applications. Always check the datasheet for specific instructions on parallel operation.

What is the difference between an AC/DC power supply and a DC/DC converter?

An AC/DC power supply is the primary power source for most equipment. Its function is to take the high-voltage alternating current (AC) from a wall outlet (e.g., 115V or 230V) and convert it into a stable, low-voltage direct current (DC), such as 5V, 12V, or 24V, that electronic components can use. A DC/DC converter, on the other hand, operates within a system that already has a DC power source. Its job is to take one DC voltage level and convert it to another. For example, it might take the main 24V bus in a control cabinet and generate a separate, isolated 5V rail to power a sensitive microcontroller. DC/DC converters are essential for creating multiple voltage levels, providing noise isolation, and regulating power from variable sources like batteries.

Why would I choose an enclosed power supply over an open-frame one?

The choice depends on your application and manufacturing capabilities. An open-frame power supply is just the bare PCB, offering a compact and cost-effective solution. It is ideal for high-volume OEM products where the supply is integrated deep inside the final product’s own enclosure. The end-product designer is responsible for ensuring safety, cooling, and EMI shielding. An enclosed power supply comes in its own case, usually metal, which provides mechanical protection, improved EMI shielding, and often simpler mounting. It is a self-contained, “plug-and-play” solution that is much easier to integrate into low-to-medium volume products, prototypes, or industrial panels, as it already incorporates many of the safety and shielding features.

My power supply is getting very hot. Is that normal?

Power supplies are not 100% efficient; they waste some power in the form of heat during the conversion process. So, it is normal for them to feel warm or even hot to the touch. However, “too hot” can be a sign of a problem. First, check the datasheet for the maximum case temperature rating. If the unit is operating within that limit, it is likely fine. If it seems excessively hot, check for a few common issues:

1. Overloading: Are you drawing more current than the supply is rated for?
2. Poor Ventilation: Is the power supply getting enough airflow? Convection-cooled units need space around them, and fans on forced-air units must be clean and spinning freely.
3. High Ambient Temperature: Is the temperature inside your enclosure higher than the power supply is rated for without derating? You may need to reduce the load or add ventilation. An excessively hot power supply will have a drastically shortened lifespan, so it is a condition that should be investigated immediately.

Conclusion

The process of selecting a TRACO POWER power supply, when approached with diligence and foresight, transcends a simple component choice and becomes a foundational act of engineering for reliability. It is a journey that begins with a precise quantification of electrical needs, moves through a sober assessment of the physical and regulatory environment, and culminates in a long-term view of reliability and economic value. We have seen how a failure to account for dynamic loads can lead to start-up problems, how the silent threat of heat can prematurely age a system, and how the labyrinth of international regulations can be navigated by choosing pre-certified components.

The distinction between industrial and medical-grade units highlights the importance of matching the component’s capabilities to the application’s specific risks and requirements. The concept of Total Cost of Ownership compels us to look beyond the sticker price and appreciate that the true cost of a power supply is measured over its lifetime, where the price of failure far exceeds the savings from a cheaper part. By employing a structured methodology, as demonstrated through case studies and the use of a decision matrix, the vast TRACO POWER portfolio transforms from a daunting catalog into a toolkit of solutions, with a right-fit option for nearly any demanding application, from a rugged industrial instrument to a life-sustaining medical analyzer. Ultimately, a well-chosen power supply is an invisible pillar of success, quietly and reliably providing the lifeblood for the technology that depends on it.