41 www.drivesncontrols.com November/December 2025 ELECTRICAL AND ENCLOSURES n n Routine inspections Establish inspection schedules by specialist (not general HVAC) teams for all of your critical equipment. n Cleaning Ensure that any ventilation pathways are unobstructed and free from dust and debris. n Temperature monitoring Deploy monitoring devices to get early warnings of any thermal issues. n Cooling systems Only use cooling systems designed for the space where the systems are sited. n Load management Ensure that transformers and VSDs are not overloaded beyond their specified ratings. n Environmental control Where practical, regulate the ambient temperature and humidity in areas housing sensitive equipment. Not surprisingly perhaps, manufacturers often default to air cooling their electrical enclosures using fans and filters. But while air cooling may be viable, it has its limitations and you should understand these before it’s installed. It’s also worth remembering that what constitutes a suitable cooling system now, may need to be adapted in future to accommodate changes in circumstances. The three main approaches are: n Air cooling Cooler external air is passed across an enclosure’s warmer internal components. Unsurprisingly, it will not work if the temperature in the production facility exceeds an allowable maximum (the setpoint) inside the enclosure, which is why we typically see a spike in equipment failures during summer. In addition, if fans are used, they can draw dust into enclosures, and this can infiltrate wire connections or internal component fans, and either prevent thermal exchange, or block and short wiring connections. Filters (or mats) can remove particulates before they enter the enclosure, but these need to be replaced regularly to prevent them from getting clogged and to ensure that a good air flow is maintained. n Active cooling This allows internal enclosure temperatures to be reduced below the local ambient temperature, even at the height of summer. Cooling systems consist of a refrigerant-based compressor circuit that modulates its performance based on the current air temperature inside the enclosure and the ambient environment. The ambient and internal air are never mixed, reducing the amount of pollution entering the enclosure, potentially attacking electrical equipment. Filters (or mats) remove particulates before they enter the enclosure, but (as with air cooling) they need to be replaced regularly to prevent them from getting clogged and to ensure that good air flows and cooling performance are maintained. Like the air cooling, regular maintenance is strongly recommended. n Liquid cooling Liquid is much more effective than air at removing waste heat and reducing temperatures in enclosures. An airto-water heat exchanger transfers heat from inside the enclosure to a flow of water. The exchanger is connected to an industrial chiller which cools the heated water, reducing it to a reasonable temperature before delivering it back to the heat exchanger. Because of this, the internal enclosure temperature can be taken below that of the local environment, even at the height of summer. Liquid cooling is extremely desirable where the environment is heavily polluted or the heat loads in an enclosure are raised to extreme levels due to the type of equipment it contains. Like air cooling, regular maintenance of liquid cooling systems is strongly recommended. A strategic imperative Inadequate cooling represents a significant, yet often underestimated (and underreported) threat to the reliability and efficiency of production lines. Climate change means that it’s likely that manufacturers will need to increase their investment in robust and energy-efficient cooling systems in future. By acknowledging the risks, and implementing proactive thermal management strategies led by experts, manufacturers can protect their critical assets, cut costly downtime, and support sustained operational efficiencies. Predictive maintenance technology, AI and data analytics, can all help them to receive early notification of impending overheating issues. Deploying effective climate management equipment is a necessary strategic investment to ensure the resilience and profitability of your business. n Common causes and symptoms of overheating in PLCs, VSDs and transformers Equipment Common causes of overheating Common symptoms of overheating/failure PLCs Poor ventilation, dust accumulation, high ambient temperatures Intermittent errors, thermal shutdowns, reduced performance, physical damage VSDs Poor ventilation, dust accumulation, overloading, high ambient temperatures Thermal shutdowns, insulation breakdown, impaired performance, drive failures Transformers Overloading, cooling system failures, high ambient temperatures Insulation breakdown, impaired performance, physical damage, catastrophic failures Best practices for thermal management of PLCs, VSDs and transformers Equipment Recommended cooling techniques Frequency of maintenance/inspection PLCs Ventilation, supplementary cooling systems, regular cleaning of vents Regular, as needed VSDs Clean ventilation, liquid cooling (for high power/temp), regular inspection of cooling system Regular Transformers Regular inspections of cooling system, oil analyses (if oil-filled), load management, ensuring proper ventilation/coolant levels Regular, annually (oil analysis) Free advice is available Rittal offers free reviews of cooling systems, based on a visual inspection of the existing enclosures and cooling equipment, and best practice suggestions to protect the systems. The service, called RiAssure, provides written reports identifying any high-risk components and enclosures, as well as recommended actions. The company may suggest more advanced investigations and provide quotes for doing so. Techniques used include using datalogging and/or thermographic measurements to gather data, as well as taking images of equipment, reviewing enclosures, and calculating the potential energy savings and ROI if new/updated cooling equipment were to be installed.
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