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The shift from pneumatic to electric drives is a well-known development in the industry. However, in recent years, this topic has gained significant momentum. This is due to the continuously increasing cost pressure and the ever-stricter requirements for CO2 reductions. In both areas, the advantages of electric solutions prevail. This blog article illustrates, using the example of OEMs in the automotive industry, how smart industrial power supplies support the transition from pneumatic to electric drives.

Electric and pneumatic drives each have their advantages and disadvantages. Pneumatic drives are inexpensive to purchase, easy to operate, offer high overload resistance, and are robust against environmental conditions such as temperature fluctuations and increased dust exposure. However, pneumatic drives require a central, continuous compressed air generation, which involves significant effort. It is necessary to distribute and maintain a consistent pressure throughout the entire factory. If there is a loss of compressed air due to a leak in the system, it must be quickly identified and repaired, which entails high maintenance efforts. Especially in applications with many switching cycles, the high energy losses due to poor efficiency are significant during operation. Even in modern compressed air systems, the majority of energy is lost as waste heat. Additionally, the compressed air system must always be ready for use and therefore in operation, which results in high energy consumption. This leads to generally high operating costs and CO2 emissions. Electric drives combined with servo motors offer better energy efficiency and enable high speed and precision. Thanks to integrated microprocessors, most electric components have a bigger range of functions and allow access to application data in connection with a central monitoring system. Operating costs are generally lower, and the CO2 footprint can be sustainably reduced. Additionally, electricity can be easily distributed in the factory – almost without losses. The ability to convert and store electricity is another advantage. New technologies, such as wireless energy transmission, also come into play. Electric solutions are also significantly quieter, which reduces noise pollution for the workforce. However, electric drives are more expensive to purchase. Additionally, the systems are more complex compared to pneumatic solutions and may require retrofitting existing equipment. OEMs are generally cautious about changes to proven systems. But the economic, political, and social pressure regarding energy efficiency is prompting more and more manufacturers to opt for the purely electric route. Therefore, new industrial plants often omit the installation of a pneumatic system right from the start. As is often the case, the automotive industry and its suppliers are taking a pioneering role in this regard. The numerous projects to switch from pneumatics to electricity that PULS has accompanied in this segment had one thing in common: the right power supply system is crucial for success.

Decentralized power supply of conveyor systems

In the automotive industry, everything from large body parts and heavy engines to components from the small parts warehouse is transported via kilometer-long conveyor belts and driverless transport systems. In the BMW plant in Regensburg, Germany the assembly lines alone have a total length of 5.5 km. When the stoppers, diverters, as well as lifting and rotating units in conveyor systems are converted from pneumatic to electric drives, a decentralized and protected power supply is ideally suited. In order to realize this, space-saving and powerful power supplies with sufficient power reserves are needed directly in the field. Long, loss-prone supply lines are eliminated, and flexibility is increased. PULS has developed the product category ‘Field Power Supplies’ for this purpose, which consists of 360 W and 600 W power supplies with high protection classes IP54, IP65 and IP67, as well as many different connector options. Additional features, such as up to four integrated current-limited outputs, ensure the safety of electrical consumers. With these eFuses integrated into the power supply, it is possible to realize selective power distribution, protection, and monitoring outside the control cabinet. The Field Power Supplies are very robust both mechanically and electrically, and resistant to harsh environmental conditions such as moisture, dust exposure, and vibrations.

Sufficient power reserves for dynamic motion sequences

For cobots, smaller robots, and decentralized applications in the automotive industry, electric drives have also become the first choice. A reason for that is also the significant technological advances in electric motors. In recent years, these have contributed to making electric drives a real alternative to pneumatics. The motors generate a lot of power with small dimensions and weight. However, the rapid movements that electric motors enable, for example in robotic applications, require power supplies that can not only handle higher loads in the short term but also process the resulting regenerative energy. Many PULS power supplies have generous power reserves, known as BonusPower. Numerous DIN rail power supplies from the proven DIMENSION product family provide up to 150 % power for 4 seconds. The FIEPOS field power supplies also achieve 200 % power for 5 seconds thanks to BonusPower. Upcoming product families for DIN rail mounting, currently in development, will even surpass these values in terms of peak performance and dynamics. Thanks to the generous power reserves, oversizing of the power supply is unnecessary, resulting in cost and space savings.

Wireless charging of autonomous guided vehicles and mobile robots

Loss-prone pneumatic drives are becoming increasingly rare in autonomous guided vehicles (AGVs) and industrial trucks. Instead, manufacturers are also relying on electric solutions here, which are better suited for mobile applications. However, for efficient power supply and battery charging during operation, an appropriate charging infrastructure is needed in the factories first. Several leading automotive manufacturers are already using the innovative wireless charging technology from the PULS Business Unit Wiferion for charging AGVs and cobots. Wiferion’s contactless charging technology allows these vehicles to remain continuously in operation without disruptive charging breaks or manual interventions. Wireless charging offers significant advantages over conventional charging systems, such as the elimination of mechanical wear or the risk of tripping hazards from cables or contact strips. With Wiferion’s etaLINK and CW systems, AGVs and mobile robots can be efficiently and autonomously charged during their normal work cycle, such as during short stops at stations. The elimination of long downtimes for energy intake increases the fleet availability significantly. The energy transfer takes place directly via charging pads, which allow for high positioning tolerance and start the charging process in less than a second. With the established 3 kW and the new 1 kW systems, Wiferion technology is currently leading in the market. The maintenance-free solutions enable a significant increase in fleet efficiency and operational safety – ideal for 24/7 continuous use in demanding environments such as the automotive and logistics industries.

Available PULS power supply solutions for an automotive factory.

Increasing system availability through application data

Every minute of system downtime is extremely costly. OEMs in the automotive industry therefore try to minimize the so-called downtime of machines and conveyor systems to an absolute minimum. With pneumatic drives, there is a risk of a leak in the compressed air system that must first be located. Electric drives are easier to manage in terms of control and preventive maintenance. PULS offers power supplies with various communication interfaces, including IO-Link, EtherCAT, and power supplies with integrated displays. This allows for easy and quick access to application data and power supply functions.

Based on the power supply data, machine builders and operators can further optimize their machines in terms of efficiency and productivity. EtherCAT (e.g., CP10.241-ETC or CP20.241-ETC) is ideal for monitoring, logging, and remote control of complex systems thanks to real-time data transmission. Power supply data is particularly advantageous within real-time control loops. Operators can control drives or other energy-intensive consumers optimally to keep the dynamic power demand within the capabilities of the power supply system. This optimal utilization of the power supplies enable improved system efficiency. In particular, the power supplies, together with other system components, enable automated responses to handle unplanned operating conditions that previously often led to downtime or even damage.

For example, the power supply provides precise measurements of the output current – that is, the load current. Using these finely sampled values, it is possible to recognize and describe digital load profiles. Based on the information about the output current, the operator can determine whether a load, such as an electric motor, changes over a longer period. This change can be an indication of wear. In the case of worn profiles, a sine wave would be recognizable in the load profile. Computer-aided data analysis helps to detect and report this anomaly early. This way, it is easy to replace the wearing component before a failure and system downtime occur.

Increasing efficiency in 24/7 operation and reducing CO2

The decision for an electric drive is only one factor that positively impacts efficiency and the CO2 balance. Power supplies with high efficiency also support this process. The higher the efficiency of a power supply, the lower the power losses and thus the energy waste. PULS now achieves efficiencies of over 96 % with its power supplies. An example calculation illustrates the importance of this value. With an efficiency of 96.4 % (e.g., with the SP960.241-S), losses of 3.6 % occur. For the corresponding power supply with 960 W output power, the power loss is thus 34.5 W, which is dissipated as heat to the environment. A thought experiment shows the significance of each percentage point in efficiency. If we reduce the efficiency to 92 %, we see increased losses of 76.8 W, more than double. Applying this to the total number of power supplies in a factory and considering the additional cooling, it significantly impacts the CO2 balance. The higher the efficiency of a power supply, the lower the energy waste and thus the CO2 emissions.

Summary: Efficient transition from pneumatic to electric drives

Increasing cost pressure and stricter CO2 reduction requirements drive the shift from pneumatic to electric drives in the industry. Electric drives offer better energy efficiency and lower operating costs, although they are more expensive and complex to purchase. Especially in the automotive industry, it is evident that decentralized power supply with powerful power supplies increases flexibility and minimizes energy losses. PULS supports the transition from pneumatic to electric drives with suitable industrial power supply solutions. This not only contributes to reducing the CO2 footprint but also makes financial sense for companies.

What is the meaning of the IP ratings for power supplies?

The IP rating indicates to what extent an electrical device is protected against the penetration of foreign objects and moisture. In this blog post, you can find out which IP codes there are, what the differences are between them and what you need to pay attention to when choosing a power supply.

Environmental influences such as dust or moisture can prevent the electrical components in a power supply from functioning correctly. In addition, the interior of the power supply may need to be protected from penetration by foreign objects, such as tools, screws and wires, and from accidental contact by the user. It is important to pay attention to the IP code (international protection code), particularly when power supplies are installed outside a cabinet. The power supply can only be used safely and costly downtime can only be avoided if the IP rating is suitable for the conditions.

What IP codes are there?

The IP code generally consist of the abbreviation IP (international protection or sometimes ingress protection) and two digits (for example, IP20, IP54, IP67 etc.).

The first digit identifies the protection against accidental contact and the penetration of foreign objects, like sand and dust into the device. The second digit indicates the protection against water and moisture.

In the case of industrial power supplies, DIN EN 60529 is the relevant standard for determining the IP rating. The ISO 20653:2013 standard is also frequently used for road vehicles. However, it only applies to electrical components in vehicles that need additional protection against pressure washing, for example with a steam cleaner.

In the context of power supplies, IP codes are occasionally confused with protection classes. While IP codes relate to the penetration of foreign objects and water and to accidental contact, the IEC protection (or appliance) classes determine the structure and insulation of power supplies with the aim of protecting users from electric shocks.

The following table gives an overview of the meaning of the numbers of the different IP ratings:

Foreign objects
o	No protection
1	Protected against solid foreign objects with a diameter ≥ 50 mm (e.g. a hand)
2	Protected against solid foreign objects with a diameter ≥ 12 mm (e.g. a finger)
3	Protected against solid foreign objects with a diameter ≥ 2.5 mm (e.g. a tool)
4	Protected against solid foreign objects with a diameter ≥ 1 mm (e.g. wires)
5	Complete protection against contact and dust
6	Complete protection against contact and fully dust-tight

Water
o	No protection
1	Protected against vertically dripping water
2	Protected against vertically dripping water when the enclosure is tilted (up to 15°)
3	Protected against water falling as a spray at an angle up to 60° from the vertical on both sides
4	Protected against water splashing from any direction
5	Protected against water jets from any direction
6	Protected against powerful water jets from any direction
7	Protected against temporary immersion
8	Protected against continuous immersion
9	Protected against high-pressure, high-temperature water jets

Which IP ratings are frequently applied to industrial power supplies?

The IP rating required depends on the installation site and the environmental conditions in each case. Power supply manufacturers that supply products to their customers ex stock generally only offer products with selected IP ratings that have become industry standards. The following table gives an overview of the most common IP ratings for industrial power supplies.

IP rating	Foreign objects		Water		Application
IP20	2	Protected against solid foreign objects with a diameter ≥ 12 mm (e.g. a finger)	0	No protection	Use in a protected environment such as a cabinet
IP54	5	Complete protection against contact and dust	4	Protected against water splashing from any direction	Use in a decentralised location outside a cabinet
IP65	6	Complete protection against contact and fully dust-tight	5	Protected against water jets from any direction
IP67	6	Complete protection against contact and fully dust-tight	7	Protected against temporary immersion

If different combinations of protection against contact and moisture are needed in special cases, customer-specific power supplies are often the ideal solution.

What do codes such as IPX4 and IP6X mean?

Electronic devices are often tested in relation to only one of the two codes for foreign objects and water.

The “X” indicates that the product has not been subjected to the corresponding tests for this code. Therefore, this is not a variable that can simply be replaced by any of the values from the table of IP ratings.

A power supply with the code IP6X offers full protection against contact and is dust-tight, but has not been tested for water penetration. In a similar way, a power supply with the code IPX4 has undergone the necessary tests for water splashing, but has not been evaluated for the penetration of foreign objects.

Which IP ratings does PULS offer for its power supplies?

PULS offers a variety of power supplies with the IP ratings described above. The products can be divided into two categories:

IP rating	Application	Product families
IP20	Use in a protected environment such as a cabinet	DIMENSION PIANO MiniLine
IP54	Use in a decentralised location outside a cabinet	FIEPOS
IP65
IP67

In the light of the increasing trend for decentralisation, the IP rating of industrial power supplies now plays a more important role than it did a few years ago. The DC supply is very often installed directly on the machines, outside the protective cabinet. To ensure the safety of employees and the correct functioning of the power supply, IP54 is required as a minimum across all system components (e.g. SPS, HMI, sensors etc.).

For these applications, PULS has developed the field power supplies in the FIEPOS product family.

Die dezentralen FIEPOS Schaltnetzteile mit hoher Schutzart IP54, IP65 oder IP67 wurden für den flexiblen Einsatz direkt im Feld entwickelt.

Figure 1: The decentralised FIEPOS switch-mode power supplies with a high IP rating – IP54, IP65 or IP67 – have been developed for flexible use directly in the field.

Summary

The IP rating describes how well a device is protected against accidental contact, foreign objects and liquids. The majority of IP codes consist of two digits. The first digit represents the protection against accidental contact and foreign objects, while the second digit indicates the protection against water and moisture. The higher the numbers, the greater the protection. Industrial power supplies that are used inside a cabinet normally have the rating IP20. Power supplies installed outside a protected environment should have a higher rating, e.g. IP54 or IP67.

Analysing backfeeding events with the help of power supply data

Power Supply

Application

Backfeeding

Backfeeding is a physical process that is highly desirable in many applications, such as electric vehicles, for the purpose of energy recovery. However, in an industrial setting, backfeeding can be a problem and lead to costly system downtimes if the power supply units fail. In this blog article you will learn how power supply data can help you to identify those backfeeding events and take measures.

Resistance to backfeeding: why is it important for power supplies?

Rotating machine components, such as drum motors, store kinetic energy which they feed back during braking in the form of voltage to the output of the power supply. On its output side, the power supply can absorb a certain amount of this energy in its output capacitors. At the same time, the output voltage increases accordingly.

The resistance to backfeeding events describes the maximum voltage allowed at the output of the power supply. If this figure is exceeded, the power supply will switch off and the system or machine will shut down.

However, even plant operators are often not aware of the backfeeding figures in real operating conditions. There is a lack of specific data concerning the frequency and the maximum values.

A detailed real-life load profile is helpful when choosing a suitable power supply during the planning phase and when analysing faults in the operating phase. The question is: how can this data be obtained?

The power supply as a data source

The power supply manufacturer PULS has developed the FIEPOS family of power supplies for decentralised use and has integrated the option of application analysis.The power supply functions like a sensor. It records a variety of application-related parameters (for example, voltage, current, temperature) and makes them available in real-time.

As the decentralised power supply is on the field level, PULS logically uses an IO-Link interface for communicating these data. Therefore, the FIEPOS power supplies function as reliable data sources and make the perfect complement to the existing condition monitoring systems. The following practical example clearly demonstrates the value that these data can add.

Application analysis with the help of the power supply

A manufacturer of intralogistics solutions planned to replace its existing 24 V power supply with a different decentralised solution. The power supply that was currently in use was constantly causing system shutdowns and it had not been possible to identify the cause.

PULS advised the company about the available solutions and made available a sample of the three-phase 360 W FPT300 power supply. With the support of application specialists from PULS, the customer evaluated the initial data after putting the power supply into operation.

The aim was to investigate three different processes:

The parallel operation of the running motors without braking.
The parallel operation of running and braking motors.
The serious case of all the motors stopping abruptly at the same time, for example in the event of an emergency stop.

In all three situations, the output voltage and the current were measured and analysed over a specific period.

Figure 1: Load profile in normal operation

As expected, in situation 1, where the motors were running, there were no noticeable problems (see Figure 1). However, the first load profile for the plant in normal operation was determined, which can help with identifying the correct size of the power supply.

Figure 2: Load profile for parallel operation of running and braking motors

In situation 2, the parallel operation of running and braking motors was analysed. In almost all cases, the energy from the braking motors resulting from backfeeding was directly absorbed by the running motors. Only one brief occurrence of a slightly increased output voltage and a negative current spike was observed, which did not present a problem for the power supplies (see Figure 2, marked in red).

Figure 3: Load profile for an emergency stop situation

Situation 3 was more critical. All the drum motors stopped simultaneously and caused a rapid drop in current and an increase in voltage to 31 V (see Figure 3).

The data analysis showed that this situation led to the system shutdowns that were mentioned initially. The capacity of the output capacitors in the previous power supplies was not sufficient in this case. As a result, the power supplies shut down.

The FIEPOS power supplies are very electrically robust. The highest permitted output voltage during a backfeeding event is 35 V/4.3 J for the FPT300. The output capacity is 18,000 µF.

As a result, the worst figure of 31 V in this example presented no problem for the power supply. As soon as the voltage fell again, the FIEPOS power supply automatically continued working in normal mode. However, it is worth mentioning here that the motor control centres from different manufacturers shut down for self-protection at a voltage of around 32 V.

The detailed inspection by the technical specialists at PULS before the customer made their purchase decision gave the customer the confidence that they were opting for a reliable, future-proof solution.

Decentralised solutions for intralogistics

Alongside its extensive IP20 portfolio, PULS is expanding its range of power supplies in protection classes IP54 and IP65/IP67 for decentralised use outside the cabinet. For system developers that means greater flexibility when planning a plant and more space in the system, together with time and cost savings.

The FIEPOS product family is based on single-phase and three-phase 360 W or 600 W field power supplies. The majority of the systems also function at 200 percent for 5 seconds. This makes them ideal for starting high-current loads and prevents the need for expensive, oversized power supplies. Over the next few months, additional performance classes will be added to the FIEPOS portfolio.

The power supplies are available with a variety of connector configurations, including M12-L/-T/-A, 7/8” and Han Q series. The power supplies from the FIEPOS eFused range have up to four current-limited outputs. These systems allow for selective current distribution, protection and monitoring in the field.

Summary

A reliable and versatile power supply is an essential feature of end-to-end decentralization in intralogistics systems

However, for this goal to become reality, power supply manufacturers must collect as much practical data as possible from the field of intralogistics to be able to offer appropriate solutions. The key is to gather and evaluate real application data.

PULS plays a leading role as an innovator in application analysis on the basis of power supply data. A global team of application engineers advises customers and users on overcoming their technical challenges. The team members can answer questions about complex application situations and identify the best solutions.

The findings from these data are also essential for the development of the decentralised power supply solutions of the future.

Efficient power supplies – An investment in the future

In the search for a suitable power supply, the costs play a major role, alongside the technical requirements. The focus is often on the initial purchase price, while other potential costs that may be incurred during the operation of the power supply are not taken into consideration. In this blog post, we demonstrate why the decision to purchase a high-quality power supply is a profitable investment for your company, by taking a close look at all the costs involved.

How do I find the right power supply?

Let’s assume for a moment that you have to select a power supply for a new project and the choice is between a CP20.241 and a power supply from another manufacturer. You already know that from a technical perspective both products are suitable for your purpose.

You have access to the device data in Figure 1 and the application data in Figure 2. Figure 1 shows that both power supplies produce the same power. The efficiency of the CP20.241 from PULS is 1.6 percent higher, which results in power losses that are 8.5 W lower. Figure 2 shows the relevant data for the operation of the plant.

Comparison of the power supplies’ basic data

Figure 1: Device data

Specifications based on the application data

Figure 2: Application data

Alongside the data from Figures 1 and 2, you also know that the purchase price of the CP20.241 is €20 more than the power supply from supplier A, which is less efficient.

You are a project buyer and you need to keep track of the project costs, so you are tending towards choosing the device with the lower purchase price.

But before you make the decision, you remember that the company has a new CFO who is currently evaluating the profitability of all the projects and who is focusing in particular on projects that are profitable in the long term. You try seeing things through the CFO’s eyes and, alongside the purchase price, you want to check the potential running costs and include them in your decision-making process.

You take a detailed look at the data and, in particular, the differences between the two devices. On the basis of the existing data, you immediately notice the power losses, which are linked to possible savings or additional costs when it comes to the electricity bill. You examine these data more closely.

Your aim is to avoid losses as far as possible. Using the power loss figures and the application data from Figure 2, you calculate the potential energy savings over one year of operation, if you choose the more efficient power supplies:

With a more efficient power supply, this is how much energy you can save per year.

Figure 3: Calculation of the energy savings per year

It emerges that the 100 power supplies you need could give you additional savings of 5355 kWh/year if their efficiency level is 95.6 percent instead of 94 percent. You calculate the potential cost savings on the basis of an electricity price of €0.11/kWh, which will remain the same for the next ten years. You discover that you can make savings of up to €589 per year over the entire operating period:

A lower energy consumption also results in lower electricity costs.

Figure 4: Electricity cost savings per year

Note on electricity costs

Electricity costs fluctuate considerably over time and vary from one region to another. This means that it is not possible to generalise. In the European Union, for example, in the first half of 2022 industrial customers were paying on average €0.18/kWh (Electricity price statistics – Statistics explained (europa.eu)). In our example, we have used a low, fixed electricity cost of €0.11/kWh and disregarded future general and inflationary price increases during the operating period. Of course, higher electricity costs also result in significantly higher savings.

Purchasing a power supply: an investment decision?

You now have the following figures available when you consider the power supplies with 95.6 percent efficiency:

Initial investment: additional costs of: 100 items x €20 = €2000
Annual saving on electricity costs of: €589

As you have already realised, your new CFO thinks in terms of cash flows, which affect the liquidity and the value of the company. You know that an investment is profitable in the long term if you get a positive figure when you add together the initial investment and all the future cash flows. You can work out the number of years of operation that it will take for an investment to pay for itself.

You calculate the impact that the decision about the 10-year runtime will have on the costs and savings. If you choose the 100 power supplies with 95.6 percent efficiency, the cash flows are as follows:

You can also work out the break-even point, which is the time when the expenses correspond to the savings.

Figure 5: Calculation of the break-even point

You discover that the savings are so considerable by the fourth year that they fully compensate for the higher initial investment. With a runtime of ten years, further savings are possible. In this example, up to €3890 can be saved if future savings are taken into consideration alongside the investment costs before the purchase decision.

Linear savings not including the net present value (NPV).

Figure 6: Savings not including the net present value (NPV)

You are very surprised by the results and you realise that focusing only on the purchase price is too simplistic and does not form an adequate basis for decision-making.

In a brief meeting, your CFO gives you the feedback that simply comparing initial investments and future cash flows can be helpful in coming to a quick, straightforward assessment of which investment is better. However, this approach is too simple to provide a reliable basis for decision-making. Your CFO explains that, wherever possible, you should also take into the consideration the change in the value of the future cash flows.

The CFO as the decision-maker on investments?

Following your meeting with the CFO, you receive an e-mail with the following information:

Dear John,
Thank you very much for the information you gave me. I think you need to extend your calculation to take into account the value of the money over time. In periods of high inflation, it is clear that future cash flows are worth less than payments made today. For example, €100 today is worth more than €100 in two years. To take these changes in value into consideration, you must discount all the future cash flows to their current value in your investment calculation. To make a decision about an investment, you need to calculate the net present value, which discounts and adds together all the current and future cash flows. This allows you to decide on an investment on the basis of realistic figures.
I have attached a detailed explanation of net present value.
Best regards
Susanne

What is net present value?

Net present value is one of the most important figures for assessing the value and the cost-effectiveness of an investment. A positive NPV means that an investment is worthwhile and will generate profits in the future.

The relevant factors in the calculation are the initial investment and all the future cash flows (inflows and outflows of funds). It is important to take into consideration the present value. Earlier cash flows have a higher value than later ones. The initial investment is then added to the discounted incoming and outgoing payments in the operating years. Alongside the payment flows, an interest rate must be included in the discount. This covers possible loan interest, the inflation rate and a risk mark-up and is normally decided on by each individual company or for each individual project.

The NPV is calculated as follows:

Formula for calculating the net present value (NPV)

Figure 7: Formula for calculating the NPV

You are very pleased to have had the input from the CFO and you try out the new calculation. To take into account inflation and loan interest, you use a fictitious interest rate of 5 percent. The result is as follows:

Possible savings taking into account the NPV

Figure 6: Savings not including the net present value (NPV)

You realise that the future cash flows discounted against the current value are much lower than in the previous calculation. However, it is clear that using this approach the investment will also start to pay for itself in the fourth year and that additional savings of more than €2500 are possible over ten years of operation.

You have now completely rejected your original idea of choosing the cheaper option with the lower level of efficiency. Despite the higher initial investment, you opt for the more efficient power supplies, which means that your company is making an investment that is profitable in the long term.

Efficient power supplies increase sustainability

It is obvious that alongside the financial considerations, the efficient power supplies also contribute to increased sustainability. In our example, in addition to the financial benefit over the 10-year operating period, there is also a reduction in CO2 emissions of around 19.6 tonnes (5355 kWh/year x 10 years x 0.366 kg CO2/kWh). Would you like to find out more about this? Then take a look at our blog post “How do efficient power supplies contribute to CO₂reduction?”

This explains how highly efficient power supplies can make a valuable contribution to more climate-friendly and sustainable industrial production by reducing energy wastage and therefore also CO2 emissions.

Summary

This simple example makes it clear that from a financial perspective the choice of a power supply should not be based solely on the initial purchase price. A calculation of this kind is too simplistic and, in many cases, will result in significantly higher costs in the future.

Our sales specialists will be happy to advise you on your choice of power supply. They will also help with investment calculations and take your specific cost factors and regional requirements into consideration. You are welcome to contact us.

In medical technology, the protection of patients and hospital staff has top priority. For this reason, medical power supplies are subject to strict requirements regarding safety, reliability and EMC. In this blog article you will find out how medical technology can benefit from the experience gained in machine building and system engineering.

Power supplies have to convert voltage as safely and efficiently as possible, while ensuring smooth operation over many years and in the tightest of spaces. Although this is a principle that applies to medical technology and to machine building alike, it is the industrial engineering segments where standard power supplies that meet these requirements are much more widespread. In turn, this means that medical equipment manufacturers are often dependent on customised rack or panel-mount power supplies.

Medical applications in hospital technology, building technology, laboratory technology and imaging diagnostics in particular stand to benefit from high industrial standards and rapid availability when it comes to power supplies. With its medical power supplies that have machine building in their DNA, PULS bridges the gap between the two fields of application.

Protection against electric shock

In addition to basic safety, EN 60601-1 primarily focuses on the functional safety of medical equipment. In the case of power supplies, this means protecting patients and operators from electric shocks in everyday hospital life – both during normal operation and in the event of a fault.

The highest protection level is 2 MOPP (Means of Patient Protection), which is intended to ensure the safety of the patient as someone who may be in a weakened state. In the power supply, this is ensured by appropriately sized clearance and creepage distances, thicker insulation between the primary and secondary circuits, and compliance with the stipulated leakage currents.

We have modified our PULS CP series of industrial power supplies in a way that ensures they fulfil the medical specifications for 2 MOPP. This offers manufacturers the flexibility and safety to use the power supplies with the ending “-M1” nearby patients without a second thought.

Protection against electromagnetic interference

Medical equipment also has to produce high levels of electromagnetic immunity to external radiation, such as mobile radio signals, but at the same time it must not interfere with the technology in its vicinity. This means that it is subject to clear regulations for electromagnetic emissions. Electromagnetic compatibility, or EMC for short, is a collective representation of the interference immunity and emissions that an item of equipment demonstrates. The limit values for medical technology are specified in IEC 60601-1-2 (Edition 4).

These specifications repeatedly present manufacturers of medical power supplies with technical challenges. Due to high-frequency noise, output ripple and noise voltage, many switch-mode power supplies cause electromagnetic interference both on the lines and through radiation.

Our development engineers reduce interference within the circuit design itself as much as possible, allowing its industrial power supplies to achieve excellent EMC values. For our medical power supplies, we have once again gone one better, ensuring successful medical EMC testing according to IEC 60601-1-2 (e.g. EN 55011 Class B for radiated interference emissions).

Protection against device failures

Reliability and durability are often key considerations in the process of selecting system components in machine building and system engineering. Many machines are designed to continue operating for years or even decades – and the same is true of medical technology. In the medical field, however, reliability takes on another dimension: to maintain patients’ health and help them recover, reliable systems are crucial.

This is an aspect that we also bear in mind when developing our medical power supplies. The focus is on maximising the minimum service life and the MTBF (Mean Time Between Failures). We provide in-depth specifications for both values and publishes this information in the datasheets for each power supply.

The key to ensuring excellent reliability and a long service life is achieving an high efficiency. The higher the efficiency, the lower the power losses and, as a result, the less heat is generated inside the power supply. This is important because a 10°C temperature increase in the power supply halves the service life of electrolytic capacitors. Although losses of this kind do not necessarily entail an immediate failure of the power supply, they do compromise the service life of the power supply as a whole.

Calculation example: When it comes to efficiency, every percentage point counts

With our medical power supplies, we achieve efficiency rates of 94.3 % to 95.2 % depending on the performance class. A calculation example illustrates the importance of this rate: if efficiency is 95.2 % (as it is in the case of the CP10.241-M1, 24 V, 10 A), losses amount to 4.8 %. With 240 W output power, the no-load losses between input and output are 12.1 W, dissipated to the environment by way of heat (see diagram 1).

To understand the importance of every efficiency percentage point, it is essential to draw a comparison with a power supply whose efficiency amounts to just 91 %: while this 4.2 % difference might not sound significant, it results in almost double the no-load losses at 23.7 W.

In a test setup, PULS ran both units in identical boxes (with a volume of 3.15 l) and under identical conditions (load: 8 A / input voltage: 230 VAC) for four hours. After this time, the temperature difference was already 7.8 °C. It is not just the power supply itself that is affected by this higher temperature: the surrounding system components also suffer.

The higher the efficiency of a power supply, the less energy is wasted and the CO2 emissions decrease.

Graphic 1: Efficiency of the medical power supply CP10.241-M1.

Apart from the service life, the MTBF also worsens as a result of high temperatures. The MTBF describes how many failures can be expected as a statistical average when operating a certain number of units over a specific period of time.

A simple example illustrates this: if the MTBF value is 1,000,000 hours, for example, this means that statistically one unit will fail every 1000 hours if 1000 units are installed. Early failures are not included in this calculation because manufacturers exclude them as part of quality assurance. The effects of wear do not play a role in the calculation of the MTBF either, as no age-related failures occur during the use phase (see diagram 2).

We make sure that both our medical power supplies and our industrial power supplies have a high MTBF (for example, at 24 V, 5 A and 40 °C, the CP5.241-M demonstrates an MTBF of 867,000 hours according to MTBF standard SN 29500). The units are therefore extremely reliable and have a very low failure rate.

Protection against noise pollution

Highly efficient power supplies offer another advantage in that they allow for passive convection cooling, something that has become the standard for power supplies in machine building and system engineering. Given that less heat is generated in the power supply overall, it can be dissipated from the unit via a cooling air flow and the aluminium housing. This means that the units do not require fans to remove the warm air – a feature that works across the entire power range.

This aspect is particularly attractive in medical technology. Fans inevitably generate noise and this can be perceived as annoying, especially if the equipment is near the patient. As a mechanical component, fans are also more frequently affected by failures.

By contrast, power supplies with convection cooling operate silently in the background, promoting a healing environment for patients and enabling maintenance-free operation.

New opportunities for developers of healthcare technology

Graphic 3: PULS offers medical power supplies for three different power classes 120W (24V, 5A), 240W (24V, 10A) and 480W (24V, 20A).

Given the high standards of hygiene that hospitals and laboratories have to meet, medical equipment designs avoid corners and edges wherever possible. This makes units easier to clean and disinfect – but at the same time, a rounded design substantially reduces the space available for electronics. Power supplies that are as compact as possible suit this scenario and are opening up new possibilities in medical design.

Thanks to the high efficiency levels of its power supplies, PULS is able to create designs that are highly compact and yet still comply with all the required protective measures for the patient environment. Most medical power supplies are larger than their industrial counterparts due to the additional insulation measures they require, such as larger clearance and creepage distances. For its medical power supplies, however, our PULS developers have succeeded in using housings that are identical to those used in standard power supplies for machine building and system engineering.

This makes it possible to accommodate 240 W in a housing measuring only 39 x 124 x 117 mm (width x height x depth). As a result, medical technology is also reaping the benefits that the progressive miniaturisation of system components is bringing in machine building.

Another industry feature that is gaining a foothold in an increasing number of sectors is the DIN rail. The most important arguments in favour of assembling system components on a DIN rail are quick installation and maximum flexibility, which enables a modular system structure. This means that individual components from different manufacturers can be combined to create a customised system that makes it possible to achieve the efficiency, performance and price levels required for the application. Another advantage of DIN rail assembly is that it allows users to mount power supplies from different performance classes on a single mounting system – something that also makes it easier to retrofit or replace components.

Summary

Manufacturers of medical devices tend to use open frame power supplies: most power supplies with medical approval available on the market are based on this design. With the M1 units in the CP series, PULS is taking a different approach. Based on our successful industrial power supplies, we are developing an expanding medical technology portfolio with solutions currently available for three different power classes: 120W (24V, 5A) ,240W (24V, 10A) and 480W (24V, 20A).

Our developers are driven by a mission to combine the efficiency and reliability found in machine building and system engineering with the safety standards that the medical sector demands. The result is secure, durable and compact medical power supplies that benefit system developers, users and patients alike.

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Wireless charging of autonomous guided vehicles and mobile robots

Increasing system availability through application data

Increasing efficiency in 24/7 operation and reducing CO2

Summary: Efficient transition from pneumatic to electric drives

What IP codes are there?

Which IP ratings are frequently applied to industrial power supplies?

What do codes such as IPX4 and IP6X mean?

Which IP ratings does PULS offer for its power supplies?

Summary

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The power supply as a data source

Application analysis with the help of the power supply

Figure 1: Load profile in normal operation

Figure 2: Load profile for parallel operation of running and braking motors

Figure 3: Load profile for an emergency stop situation

Decentralised solutions for intralogistics

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How do I find the right power supply?

Note on electricity costs

Purchasing a power supply: an investment decision?

The CFO as the decision-maker on investments?

What is net present value?

Efficient power supplies increase sustainability

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What is MTBF?

How is the MTBF calculated?

How to visualise the MTBF?

How is the failure rate λ determined in practice?

Good to know!

What is the difference between MTBF and service lifetime?

Why are the MTBF and service lifetime of a power supply important?

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What does system availability mean?

The risk of poor power grid quality

The power supply unit as a component of a power supply system

Load protection by electronic circuit breakers

For safety-critical loads, a DC UPS is recommended

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Does a systems approach make more sense than stand-alone devices?

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Maximizing utilization vs. minimizing downtime

More total power – How does a parallel connection work?

What types of parallel connection are there for power supplies?

How do I set up a parallel connection correctly?

Higher availability – What is a redundant power supply system?

What types of redundancy are there?

1+1 redundancy

N+1 redundancy

What should you pay attention to when using redundancy?

Conclusion

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Is daisy chaining recommended for power supplies?

What is the alternative to daisy chaining?

Conclusion

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Multimeter, wattmeter or power analyzer – which is the (measurement) tool of choice?

Tip:

Avoiding mistakes in the measurement setup

Taking environmental conditions into consideration

Conclusion

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Protection against electric shock

Protection against electromagnetic interference

Protection against device failures

Calculation example: When it comes to efficiency, every percentage point counts

Protection against noise pollution

New opportunities for developers of healthcare technology

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