EMC Testing for Typical Power Devices in the TPS Lab
At TPS, our EMC and safety lab is built around the kinds of hardware we design and ship every day. That means power electronics and industrial systems, not only small consumer devices. When customers ask what we can test, they rarely say “IEC 61000 device class X”—they say things like “a rack mount power supply in an industrial control panel” or “a DC power system with battery backup”.
This overview connects to the EMC and Safety Testing page and explains how we approach EMC testing for five typical device categories:
Why the Device Type Matters for EMC Testing
From a standards point of view, many products fall under similar EMC rules. But in the lab, a DIN-rail power system inside an industrial control panel behaves very differently from a small OEM module or a portable charger, even if all of them deliver 24 V or 48 V.
Some of the factors we consider when planning EMC tests are:
- Mechanical form factor and mounting. Rail-mounted supplies, rack-mount units and board-level OEM power modules have very different return paths, enclosure effects and grounding schemes.
- Cables and connections. Long field wiring in industrial control panels or DC power systems can act as antennas, while very short leads in a prototype may hide real-world problems.
- Neighbouring electronics. PLC control systems, industrial ethernet switches and other digital boards next to the power hardware can be both victims and sources of interference.
Understanding these details up front helps us define realistic EMC test setups and avoid surprises when you later go to a third-party certification lab.
DIN-Rail and Rack-Mount Power Systems
DIN-rail and rack-mount power systems are the backbone of many automation projects. In real cabinets we see combinations of DIN-rail supplies, DC distribution, I/O modules and sometimes a 48 V or 24 V rack mount power supply feeding a larger system.
For EMC testing we typically focus on:
- Cable harnesses. Field wiring, sensor cables and communication lines are represented by realistic cable bundles and terminations in the test setup.
- Cabinet-level grounding. How the DIN-rail supplies tie into earth and protective bonding strongly affects emissions and immunity inside industrial control panels.
- Worst-case loading. We exercise several outputs at the same time, especially when the power system feeds both logic and actuators.
In the dedicated case study for this category, we will walk through an EMC project on a DIN-rail and rack-mount system used in an industrial control panel, from pre-compliance checks to final debug.
AC-DC and DC-DC Power Supplies
Standalone AC-DC and DC-DC power supplies show up in many shapes: enclosed units with fans, open-frame boards and plug-in modules. Some are configured as rack mount power supply units, others are small OEM boards on a backplane.
When planning EMC tests for these supplies, we look at:
- Input configuration. Single-phase, three-phase and different earthing schemes change the conducted emission and immunity setup.
- Load profiles. Worst-case behaviour may be at minimum load, full load or at transitions, so we test several operating points.
- Cooling and enclosures. Fans, vents and mounting plates influence radiated behaviour and ESD paths.
A separate AC-DC / DC-DC EMC case will show how we handle supplies used as part of test racks and embedded in larger machines.
Battery Chargers and DC Power Systems
Battery chargers and DC power systems bring extra dynamics into EMC testing. We often deal with systems that include a charger, batteries and a DC distribution network or DC power management system supplying several loads.
Important EMC points here include:
- Changing operating point. Emissions and immunity sensitivity can vary across the charge cycle and at different DC bus voltages.
- Battery or load simulation. Where possible we test with real batteries; otherwise we create DC loads that mimic the application closely enough for meaningful EMC results.
- Interfaces to the rest of the plant. Monitoring systems, communication links and safety circuits are considered in the EMC test plan.
In the planned charger and DC power system case study we will show how a real project moved from first pre-compliance measurements to a robust DC power system ready for certification.
Control, Monitoring and Communication Boards
Inside cabinets and test racks, we frequently see control and communication electronics next to the power hardware: PLC control systems, custom controller boards and industrial ethernet switch products that tie everything together.
From an EMC perspective these boards are both potential noise sources and sensitive victims:
- Digital activity. Fast serial links and switching regulators can create local emission hot spots if layouts and cabling are not carefully designed.
- Susceptibility. ESD, EFT and surge pulses on I/O lines or power rails can cause resets, lost messages or incorrect readings in plc control systems and other logic boards.
- Shielding and grounding. How industrial ethernet switches and other communication boards are bonded to the cabinet and cable screens has a direct impact on EMC performance.
A dedicated control and communication board case will show how we exercised a cabinet with PLC control systems and ethernet switches under immunity tests and eliminated random resets.
OEM Power Modules and Electronics Inside Larger Systems
Many customers ship their own machines and equipment and use TPS as a partner for both power hardware and EMC. In these projects we often test OEM electronics and power modules that will later sit inside an industrial panel OEM design or other machinery.
Typical questions for this device type are:
- What is the reference setup? We agree how the OEM module will be mounted, wired and loaded during EMC tests so the results are meaningful for integrators.
- How will system integrators use the data? Reports clearly state assumptions and limits so that OEM customers and electronics OEM partners understand the conditions.
- What integration risks remain? Follow-up tests on complete cabinets or machines can confirm that the OEM modules behave well once combined with other hardware.
Later, the OEM power module case study will highlight how we supported an OEM customer through module-level EMC testing and system-level integration.
Preparing Your Device for EMC Testing at TPS
Whether you are bringing a DIN-rail system, a rack mount power supply, a DC power system, plc control systems or OEM electronics, a little preparation makes EMC testing more efficient and more useful.
Before contacting our lab, it helps to collect:
- A short description of the device and its main application.
- Target markets and standards, or comparable products you want to match.
- Basic ratings such as input and output voltage, current and power.
- Information about cables, harnesses and mounting, especially for industrial control panels and cabinets.
- Any previous EMC test results, if available.
With this information we can propose a focused EMC test plan, schedule a pre-compliance or debug session in our lab and later, if needed, support you when you work with a third-party certification house.
