How to Choose the Right Power Supply for Automation Needs

Automation has become a transformative force for bolstering productivity and minimizing output errors across countless sectors. While items like sensors, controllers, and actuators enable the complex tasks that automated systems can perform, without the right power supply, even the most advanced system cannot operate effectively. In this guide, we will break down the most important factors to consider when selecting a power supply, as well as explore some different types that are common in automated systems.

Power Supply Requirements

Before attempting to select a specific power supply variant, it is vital to consider parameters like:

• Voltage and Current Ratings: The power supply’s output voltage and current must match the intended system's load requirements. Undervoltage can lead to malfunction, while excess current may damage connected components.
• Total Power Demand: Calculate the full system load and apply appropriate safety margins (typically 20–30%) to avoid overloading the power supply.
• Hold-Up Time: This refers to how long the power supply can maintain output during brief power interruptions, with adequate hold-up time usually being ≥20 ms.

• Protection Features: Power supplies should implement safeguards such as:
  • Overvoltage protection (OVP)
  • Overcurrent protection (OCP)
  • Short circuit protection (SCP)
  • Overtemperature protection (OTP)
  • Inrush current limiting to prevent damage during power-up
  • Parallel or redundant configurations with load sharing and automatic failover, particularly in systems that should not be interrupted
• Environmental Resilience: The power supply has to be rated for anticipated conditions like:
  • Temperature extremes
  • Humidity and condensation
  • Dust, dirt, and airborne contaminants
  • Shock and vibration
• Efficiency: High-efficiency power supplies reduce energy waste and heat buildup.
• Interoperability: Ensure compatibility with other automation components and control systems, including adherence to electrical interface standards and support for required communication protocols when applicable.

Notable Power Supply Types

Linear Power Supplies

Linear power supplies are valued for their reliable, interference-free power delivery in sensitive analog circuits. These units operate by stepping down AC voltage through a transformer and converting it to DC using linear regulation. Moreover, they present:

• Stable and clean DC output with very little ripple
• Minimal electromagnetic interference (EMI)
• Simplified internal design, using fewer components and passive regulation
• High precision in voltage regulation

However, linear designs suffer from low efficiency due to the heat dissipated through resistive regulation, especially under high load conditions. They also tend to be bulky and heavy because of the large internal transformers they use.

Common Applications

• Laboratory instrumentation
• Analog control systems
• Signal amplification in automation

Switching Mode Power Supplies

Switching Mode Power Supplies (SMPS) seamlessly convert AC to regulated DC output with features like:

• Efficiency around 80–95%, helping avoid wasted energy and minimizing heat generation
• High-frequency switching, allowing for smaller transformer size and a compact footprint
• Support for wide input voltage ranges, often with automatic adjustment for varying power conditions
• Integrated overcurrent, overvoltage, and thermal protection circuits

Despite these benefits, SMPSs can introduce higher output ripple and switching noise compared to linear supplies. They may also produce EMI if not properly shielded or filtered.

Common Applications

• Programmable Logic Controllers (PLCs)
• Human-Machine Interfaces (HMIs)
• Industrial communication equipment
• Distributed I/O modules

DIN Rail Power Supplies

DIN rail-mounted power supplies are a preferred choice in automation control panels, particularly when modularity and saving space are priorities. They are engineered to snap onto standardized 35mm DIN rails, simplifying installation and maintenance. Additionally, they offer:

• Wide input voltage compatibility, suitable for global applications and varying power conditions
• Screw terminal connections for secure and convenient wiring
• LED indicators and status diagnostics, aiding quick fault detection
• Active Power Factor Correction (PFC) in many models, which boosts input efficiency and reduces harmonic distortion

Although they are built for compact spaces, adequate ventilation is crucial to prevent thermal buildup and performance degradation. Moreover, DIN rail power supplies are often limited in total power output compared to rack-mounted or standalone units.

Common Applications

• Distributed control systems
• Compact automation enclosures
• Factory floor installations
• Sensor and actuator interface modules

Alpha Industrial Parts: A Reliable Source for Power Supplies

The capabilities of automation systems starts at the power level, with the most fitting option bolstering system longevity and energy use. As choosing a power supply is a strategic decision that partially dictates performance, having access to trusted and compliant options simplifies this process. Alpha Industrial Parts, an ASAP Semiconductor-operated platform, is a one-stop source for power supplies and related automation components.

Everything on this website is held to high quality standards, with all products being sourced from verified manufacturers and suppliers. This commitment, coupled with our team consistently presenting competitive pricing, fast lead times, and curated procurement solutions, means you can anticipate an ideal experience every time. To learn more about our unrivaled parts and services, check out our selection and connect with our specialists at any time.

1. olivia moore
2. Posted on July 27, 2025
aviation

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