• • • ENCLOSURES • • • Thermal management


and cooling Thermal management is an important design consideration for any electrical or electronics enclosure. Thermal overload can be a common reason for operating failures in electronic devices causing damaging and costly system downtime. The risk is increasing for equipment mounted


into cabinets as the power density of modern electronics systems continues to grow, increasing the heat generated inside the cabinet. Heat dissipation calculations are measured in T (Delta T), which is defined as the temperature difference between the intake air and exhaust air, or the amount of heat that is carried away by the stream of air exiting the heat load. A greater temperature difference signifies more heat being removed. Cabinets designed for universal applications


require broad thermal management compatibility and often need to meet more stringent performance demands than standard communications cabinets. There are numerous thermal management and


cooling options that may be deployed in cabinets, from high perforation (referred to as a passive option), to fan trays, heat exchangers and air conditioners (all considered as active options). Additional information regarding heat


management design standards and recommendations are defined in IEC 61587-1.


standard cabinet on a platform that can move in any direction and simulate the earth’s movements during a seismic event. Particular deformation and movement of the cabinet components can lead to test failure.


Electromagnetic compatibility


(EMC) Electromagnetic interference (EMI) is a constant concern for equipment manufacturers. As electronic systems become ever faster and are integrated into all types of manufacturing, production and automation environments e.g. Industry 4.0, SMART factories and intelligent buildings, the issue of EMI has become critical. Environments that were once considered


EMI-free are becoming more and more susceptible to interference due to an increase in automation equipment and attendant electronics emissions. Visual inspection alone of cabinet gaskets does not suffice to ensure adequate EMI protection. Proper tests and results are needed to ensure that a cabinet design meets the application requirements. Gasket integration to provide a Faraday effect is


not a simple matter as it may compete with requirements such as cabinet cooling and perforations for air flow. The latter demands an understanding of the entire system, not just individual components, and necessitates a number of accessories that may appear redundant but solve very specific problems. Additional design requirements and recommendations can be referenced in IEC 61587-3.


Shock & vibration protection There are two main dynamic requirements to mechanical stability– seismic and shock/vibration (S/V) tests. It should be understood that seismic and S/V tests are very different and each have very well-defined processes for loading cabinets with weight. Retesting with exact equipment is needed to


ensure that the final solution offers the actual S/V or seismic protection that is required. The test may not be needed if the equipment is below the threshold of the official test requirements.


Shock and vibration This is the go-to test for equipment that will be used in mobile applications and simulates a typical environment within a train car or vehicle, or close to vibration-generating equipment such as a punch press or similar industrial machinery. Minimisation of weight and S/V–optimised designs offer long-term benefits to users, especially in transportation applications.


Seismic Seismic activity is a very complicated but well- studied phenomenon. Testing equipment and processes are well defined and well known, with multiple laboratories capable of carrying out testing. The test consists of placing a fully loaded


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Environmental and safety IEC 60529 provides guidance for classifying the ingress protection rating (IP Codes) of enclosures. IP deals with dust and water protection. Equipment that has better protection against dust, objects and water will have higher ratings. IP ratings have two numbers - one shows


dust/object protection and the other shows water protection. There a number of industries where the


requirements will be higher than in others; these include transportation, military and food and beverage processing, which will have high requirements for IP rating to ensure system reliability, process and operator safety.


Sourcing an enclosure It is beneficial any equipment designer or systems integrator to partner with a supplier that has a solid understanding and experience of the many electrical, electronic and mechanical requirements that must be considered when specifying an enclosure. Access to accessories such as internal


hardware, cable access, strain relief and EMC control provides a single source of supply for the complete project, ensuring component compatibility and simplifying the specifying and sourcing process.


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