Authors: Michael Peters, Business & Product Manager at Recom, and Ralf Kern, Line Manager at Rutronik
Greater efficiency in the electrical cabinet
Modern automation requires compact, robust, and low-maintenance power supply solutions. New concepts focus on high power reserves, intelligent protection mechanisms, and easy integration, even in demanding industrial environments.
Authors: Michael Peters, Business & Product Manager at Recom, and Ralf Kern, Line Manager at Rutronik
A reliable power supply is the foundation of any automation solution. Requirements are particularly demanding in industrial applications: intelligent systems, compact electrical cabinets, high ambient temperatures, and increasingly shorter maintenance cycles place strict limits on conventional power supplies. Selection is becoming increasingly focused on the complete system, including additional functions, service life, and ease of installation.
Selection criteria for power supplies in industrial automation
Selecting the right power supply for industrial automation is crucial, as it directly impacts the reliability, efficiency, and safety of the entire installation. Modern manufacturing environments place high demands on power supplies, as they operate continuously and often under harsh conditions. Therefore, various technical and economic aspects must be carefully considered to ensure reliable and cost-effective operation.
- Stable output voltage, even with fluctuating loads and adverse environmental conditions.
- Overload, overvoltage, and short-circuit protection is essential to prolong the lifespan of both the power supply and the end equipment.
- An efficiency greater than 90% reduces energy losses and minimizes heat generation.
- DIN rail power supplies allow for flexible expansion and easy maintenance.
- Compliance with regulations such as UL, CE and RoHS ensures suitability for global industrial use.
- Modern remote monitoring and diagnostic functions increase the availability of the installation.
- In addition to the total power required by all loads, a reserve of at least 25% must be provided.
- Especially in applications with motors or actuators, the power supply must withstand temporary load spikes without needing to be oversized.
- Factors such as temperature range, humidity, vibrations, and dust exposure must be taken into account.
- Tool-free installation, compact design, and simple diagnostic functions make installation and maintenance easy.
- Durable components and a high mean time between failures (MTBF > 80.000 hours) offer economic advantages.
It is clear that modern power supplies must do much more than simply provide stable power to meet the demanding conditions of industrial environments.
To ensure a reliable long-term supply, the thermal behavior of power supplies must be considered from the design phase. Power derating begins at ambient temperatures above 60°C: the maximum available power decreases depending on the temperature and the installation environment. Therefore, it is essential for electrical cabinet planners and manufacturers to consider derating curves, especially in applications with high mounting density or limited ventilation.
Compact, powerful and ready for peak loads
The Racpro1 series has been specifically developed to meet these requirements (Fig. 1). The tool-less push-in terminals with a 25° design allow for quick and maintenance-free integration into the DIN rail. Furthermore, the devices offer a compact design (starting at 43 mm wide), active inrush current limiting, and a service life exceeding 80.000 hours at 40°C under full load.
To minimize heat loss, the housing design takes advantage of the chimney effect: hot air rises through vertical channels, generating a cooler airflow from below. This natural convection ensures efficient heat dissipation without the need for fans and guarantees full device performance at ambient temperatures up to 60 °C (Fig. 2).
In addition to the case design, the optimized printed circuit board (PCB) design also contributes to thermal and electrical stability. Large copper areas for heat dissipation, strategic placement of heat-generating components, and optimized airflow guidance ensure efficient passive cooling. This increases component lifespan and reduces the likelihood of failure under full load.
Another important advantage is the power reserves: in addition to providing continuous power at an ambient temperature of 60 °C, the devices offer 120% additional power at 45 °C and a 150% power boost for five seconds at 60 °C, ideal for sudden load changes.
The system is complemented by 4-channel electronic fuses (e-Fuses), which allow monitoring of the 24 V circuits. Thanks to selective protection, individual loads can be disconnected in the event of a fault, ensuring that critical systems, such as controls, remain operational. Diode circuits based on MOSFET technology allow the connection of multiple low-loss power supplies for redundant power supply to safety-critical systems or to increase available power. Active inrush current limiting also protects the contacts of upstream circuit breakers. Table 1 shows a comparison of the Racpro1-T240, -T480, and -T960 models.
| Racpro1-T240 | Racpro1-T480 | Racpro1-T960 | |
| Ancho Steak: | 43 mm | 52 mm | 80 mm |
| Efficiency | Up to 94,1% | Up to 95,3% | Up to 97,1% |
| Functional characteristics | Active inrush current limiting; two-phase AC operation from 2×350 V to 2×575 V | PFC > 0,9 and active inrush current limiting; passive load distribution in parallel operation and LED load indicator | PFC > 0,9 and active inrush current limiting; passive load distribution in parallel operation and LED load indicator |
| Weight | 500 gr | 800 gr | 1140 gr |
Table 1. Comparison of the three Racpro1 models
Summary and outlook
In modern industrial automation, power supplies are no longer passive components, but central system elements. They must combine energy efficiency, operational reliability, and ease of maintenance. Beyond simply supplying power, they are increasingly taking on diagnostic, protection, and communication functions. To meet these requirements, today's power supplies must not only be powerful and compact, but also feature intelligent protection mechanisms and robust designs.
The Racpro1 series power supplies are designed for centralized and decentralized use in electrical cabinets or directly on the machine. Combined with electronic fuses, redundancy diodes, and uninterruptible power supplies (UPS), they form a modular power system that is fully DIN rail compatible and easy to integrate (Fig. 3). Rutronik supports the implementation of future-proof power architectures, from source to load, through a comprehensive product range, technical advice, and system expertise.
