Enclosures
Keeping equipment
safe
One of the most important things to remember when specifying an electrical system integration is the system enclosure and its ancillaries. The enclosure design is vital to protecting system longevity and ensuring the effective performance of the drives within. Philip Glenister, product manager of Rittal explains the art of good enclosure design
T
he right enclosure can have a huge impact on the overall performance, safety and efficiency of an electrical system. Get it right, and it can significantly prolong the life of the installed equipment, as well as save energy, utility costs and protect against unscheduled down-time. Get it wrong, and the business risks shortening the life of the system or, worse, total system failure – which is not that uncommon, unfortunately. So what are the main concerns when designing a system?
Temperature control and system failure
Electrical equipment is obviously highly sensitive to temperature changes and moisture levels. A typical operating ambient
temperature for electrical equipment is 35°C. If the air in which it operates is warmer than this because heat is not being effectively dissipated, the system will be running hotter than it should. Control system components typically
fail more frequently as temperatures rise, so if climate control is not in place, the service life of a system will be shortened - and a business could be faced with total system failure. Unfortunately, all too often, thermal performance and climate control can be something of an afterthought. The result is typically a poor and ineffective cooling solution which is expensive to run and which leads to expensive down-time due to premature component failure.
So, if you are designing a system, the first things to consider are: a) The environment in which the final overall system will be operating. b) The internal environment required by the installed equipment and how to control this throughout the system’s lifecycle. This hopefully underlines the point that thermal performance, more than any other single element of the design, must form the baseline for the design of any enclosure. The good news is that designing climate control systems is relatively easy with software, such as Rittal Therm, which simplifies the calculation of climate control requirements and eliminates the associated laborious calculations.
Material considerations The material the enclosure is built from, and its surface finish, are also extremely relevant in determining the long term success of a system – and there is quite a choice. Rittal’s enclosures, for example, can be made in carbon steel, 304 and 316 stainless steel, cast aluminium, sheet aluminium, polycarbonate plastics and GRP. Stainless steel should always be used
in more environments where there is likely to be more risk of corrosion - such as outdoor, coastal, chemical and heavy pollution. It would also be the material of choice where clean environments are paramount, such as the manufacture of food and beverage, hospitals or pharmaceuticals.
It exhibits exceptional corrosion
resistance whether in its raw state or powder coated, but be aware that if the surface is contaminated with carbon steel then the enclosure can show signs of surface corrosion. Sheet aluminium is another solution for many outdoor locations and can be more cost effective than stainless steel. It provides a high degree of corrosion protection and is powder coated for a tough finish. It can also be coated with an anti-graffiti finish making it easy to remove paints and adhesive residues from posters. Sheet aluminium also provides the added advantage of being lightweight making it easier to install without the use of expensive lifting equipment into the less accessible places.
Non-metallic enclosures such as plastics
and GRP impregnated plastics are more suited to the smaller range of electrical enclosures. This type of enclosure provides robust mechanical strength and electrical insulation properties. It also provides an
32 July/August 2015 Components in Electronics
extremely high degree of corrosion protection. It can discolour under certain light conditions but this does not harm the material properties of the enclosure. Ingress protection (IP) and National Electrical Manufacturers Association (NEMA) are the industry standards for the ingress protection of enclosures. An enclosure with a high ingress
protection category rating (of IP67 for example) is important on two levels. First, where dust can’t get in, heat cannot get out - at least not without help. So you must employ some form of climate control. However, on the flip-side, a sealed
enclosure will stop cooled air escaping, which minimises energy wastage, while the level of condensate produced by any cooling solution will also be kept to a minimum.
A NEMA classification outlines the
protection of individuals from unintentional contact with equipment and the protection of an enclosure from external factors in much the same way as IP ratings.
Easy maintenance
Part of a well designed system considers the access for maintenance and repairs. It’s an important benefit to the end user that down-time for maintenance is kept to a minimum. With a good system design, maintenance, critical components and procedures are integrated into the overall system and the type of enclosure and accessories selected play a major part in the process.
Selecting something as simple as a door stay to hold the door open at a set angle can make it easier for the operative to change the fan or filter, as well as for the operator working on a solid object within a designated area around the enclosure and not in front of a live open system.
Accessories
Having available an extensive range of accessories for the enclosure completes a well designed system. These range from providing effective cable management solutions at high or low level (using the plinths for cable routing) to internal lighting which can be operated when opening the door for service and maintenance. All Rittal’s accessories have been designed and developed to make the installation, fit out or maintenance as simple, safe and as easy as possible.
www.rittal.co.uk www.cieonline.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45