Protecting Electrical Enclosures

December 15th, 2011 by Friedel Coetsee Friedel Coetsee

It is a well known fact that power densities have become more through cabinet volumes becoming smaller. The components of the packaging of the electrical enclosures makes the possibility smaller for circuit size and makes the speed more but it also leaves little room for dissipation of heat. With the technological advance of industrial plants becoming more dependent on state of the art microprocessors, logic controllers that are more programmable as well as having variable frequency drives, the question of proper heat dissipation has become very important.

The restriction of airflow through tightly packed cabinets and panels within the electrical enclosure makes for the internal temperatures to rise to a high level. The testing of the thermal level has shown that the traditional way of cooling by convection is not good enough for the more modern high-power-density enclosures. The more popular way of cooling is still through the use of fans called forced convection. This can make for heat moving rates that are about 10 times better than what is possible with natural fanning or radiation.

Although so, these rates are still not enough to cool faster electronic components when they are in difficult environments as with a plant. To make junction temperatures less and prevent failure of control on high density controls, it is very important to lower the internal temperature to less than normal room temperature. It has been proven that for every 10 grades Celcius increase, shutdowns will happen twice as often as when the temperature is lower.

The manufacturer will therefore stipulate the exact temperature at which the electrical enclosure will most optimally function. As there is a constant need to lessen the cost and size of all electronics while at the same time making the speed and quality of the design better, it has caused a lot of stress among designers and manufacturers alike. As mentioned above, the most popular way of cooling is through a fan-based system, as they are easy and less expensive to install than any alternative cooling mechanism. There is one problem with the installation of the fans though, and that is that, with installation, invisible oil aerosols that are in the air of the factory, go into the fanning system upon installation. This in its turn attract and keeps the dust which in time forms an insulating blanket over the board and also promotes the buildup of heat that will in turn result in mechanical failure of the fan.

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