DIN rail PSUs are standardized and simple to install. The basic requirements are fixed (single-phase or occasionally 3-phase input, a selection of standard outputs, and power ratings), simplifying many design decisions. In addition, the required input voltage range for most low- or medium-power AC/DC supplies is standardized worldwide at 90VAC-264VAC, with only minor variations between countries. That said, there are still a few specifications that can present challenges.
Choosing the Right DIN Rail Power Supply for Your Application
Oct 18, 2024
DIN rail power supplies offer several advantages over traditional power supplies. They are modular, easy to install, and space-efficient. They mount on a DIN rail, making them ideal for applications where space is limited or where easy access to power is required. They come in various sizes, voltages, and wattages, catering to different application needs.
Table of Contents
DIN Rail Power Supply Considerations
Operating temperature
Ensure the power supply does not exceed its rated operating temperature. Temperatures outside this range can cause various issues. High operating temperatures can lead to derated performance, reduce operating life, and increase the risk of malfunctions or failures. Low temperatures can also affect performance, including increased output ripple and poor output regulation. In addition, changes in electrical characteristics at low temperatures may prevent proper startup. When selecting a DIN rail power supply, confirm that the unit meets requirements at the maximum operating temperature, accounting for derating if necessary. Also, verify that the unit is guaranteed to start at the lowest operating temperature.Voltage Drop in Long Power Cables
Long cables can incur resistive losses that reduce the voltage at the load below allowable limits. To counteract these losses, there are two main approaches:- Use cables with a larger cross-section to reduce resistance
- Increase the output voltage (e.g., from 24V to 48V) and step it down near the load using a local DC/DC converter
It is recommended to calculate the maximum voltage drop and verify that the power supply still delivers sufficient voltage to the load under worst-case conditions.
Capacitive and Inductive Load Effects
Powering these types of loads can create challenges. Inductive loads, including motors, solenoids, and relays, can produce high voltage spikes. Supplying capacitive loads can reduce the dynamic load response of the power supply or cause instability and increased output ripple. Ensure the power supply can accommodate the load types required by the application.Application-Specific Safety and EMC Certifications
Applications in many fields require appropriate safety and EMC certifications for power supplies. Examples include:- IEC/EN/UL/CSA62368-1 is a product safety standard that classifies energy sources, prescribes safeguards, and provides guidance on their application. Its goal is to reduce the likelihood of injury, property damage, or fire hazards. This standard applies to a wide range of technology products.
- IEC/EN/UL/CSA61010-1 is a safety standard for electrical equipment used in measurement, control, and laboratory applications. The 3rd Edition introduced a risk assessment procedure covering equipment with human interaction, such as displays or controls.
- EN55032/35 EN 55032 are standards related to electromagnetic compatibility (EMC) for multimedia equipment.
- EN 55032 (CISPR 32) defines tests to identify electromagnetic emissions from equipment with rated AC or DC supply voltages not exceeding 600V. It covers both radiated and conducted emissions.
- EN 55035 (CISPR 35) focuses on immunity—how well equipment withstands external interference. Manufacturers must assess all product functions for immunity and meet specified testing and monitoring requirements.
- EN 61204-3 specifies EMC requirements for switch mode power supply (SMPS) units supplied by source voltages up to 1,000VAC or 1,500VDC, providing AC and/or DC output (except inverter outputs that establish AC mains). The standard ensures compliance with EMC criteria, minimizing interference and ensuring safe operation.
- EN 61000-6-4 specifies emission requirements for electrical and electronic equipment in industrial environments, covering 9kHz to 400GHz. EN 61000-6-4 Class B refers to devices suitable for residential and similar areas with lower emission limits.
Designers must verify that the power supply complies with applicable safety and EMC requirements.
RECOM DIN Rail Power Supplies for AC/DC Applications
RECOM has offered DIN rail DC/DC converters for many years and is now launching the REDIIN series of DIN rail AC/DC power supplies with 90V-264V input ranges and 120W, 240W, and 480W power ratings, along with the RACPRO1 family with 240W, 480W, and 960W ratings.
REDIIN series applications include power solutions for measuring and testing equipment, industrial control and automation, power generation and distribution, and data and telecommunications systems.
RACPRO1 series applications cover industrial automation, smart manufacturing, renewable energy and microgrids, transportation, power distribution, battery storage systems, and test and measurement equipment.
These products incorporate innovative RECOM design technologies achieving efficiency ratings up to 93.5%. The devices are available in standard DIN rail format with widths of 30mm (1.2"), 40mm (1.6"), or 56mm (2.2") for the 120W, 240W, and 480W versions respectively; all units measure 123.4mm (4.86") in depth and 123.6mm (4.87") in height. The REDIIN 240W and 480W units provide 24V and 48VDC outputs, while the 120W version also includes a 12VDC output. Output voltage is adjustable from the front panel.
Operating temperatures range from -30°C to +70°C with convection cooling, derating from +50°C, and cold-start capability down to -40°C. Protective features include overvoltage, short-circuit, and overcurrent protection, along with constant current mode for safe startup under high capacitive loads. Convection-cooled units operate at full power from -30°C to +50°C (230VAC) and support inductive and capacitive loads.
The REDIIN series is certified to the safety standards discussed above: IEC/EN/UL 62368-1, IEC/EN/UL 61010-1, and IEC/EN/UL/CSA 61010-2-201. Electromagnetic emissions comply with heavy industrial EN 61000-6-4 Class B and EN 61000-6-2 immunity standards. The products meet environmental protection requirements according to the RoHS Directive.
RACPRO1 series applications cover industrial automation, smart manufacturing, renewable energy and microgrids, transportation, power distribution, battery storage systems, and test and measurement equipment.
These products incorporate innovative RECOM design technologies achieving efficiency ratings up to 93.5%. The devices are available in standard DIN rail format with widths of 30mm (1.2"), 40mm (1.6"), or 56mm (2.2") for the 120W, 240W, and 480W versions respectively; all units measure 123.4mm (4.86") in depth and 123.6mm (4.87") in height. The REDIIN 240W and 480W units provide 24V and 48VDC outputs, while the 120W version also includes a 12VDC output. Output voltage is adjustable from the front panel.
Operating temperatures range from -30°C to +70°C with convection cooling, derating from +50°C, and cold-start capability down to -40°C. Protective features include overvoltage, short-circuit, and overcurrent protection, along with constant current mode for safe startup under high capacitive loads. Convection-cooled units operate at full power from -30°C to +50°C (230VAC) and support inductive and capacitive loads.
The REDIIN series is certified to the safety standards discussed above: IEC/EN/UL 62368-1, IEC/EN/UL 61010-1, and IEC/EN/UL/CSA 61010-2-201. Electromagnetic emissions comply with heavy industrial EN 61000-6-4 Class B and EN 61000-6-2 immunity standards. The products meet environmental protection requirements according to the RoHS Directive.
Conclusion: Selecting the Right DIN Rail AC/DC Power Supply
The DIN rail is the most popular mounting system in industrial control applications, and compatible components and modules are widely available. Although specifying a DIN rail supply simplifies design since many parameters are standardized, potential challenges remain. RECOM’s new DIN rail AC/DC power supplies offer outputs from 120W to 480W at various voltages, providing a robust, cost-effective solution for numerous industrial and factory automation applications.
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REDIIN120
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REDIIN240
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REDIIN480
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