November/December 2019

n CONTROLGEAR AND ENCLOSURES Audi plant acts as testbed for cabinet cooling systems W hile the components used in control cabinets are generally becoming smaller – particularly in the case of power electronics – their heat dissipation is increasing, and cabinets are therefore getting hotter. To counter this trend, manufacturers of cabinet air-conditioning systems have been improving the efficiency of their cooling systems. But the way the cabinets are wired can also have an effect on their internal temperatures. One approach to cutting heat levels is to do away with conventional mounting plates and trunking, and to separate the heat-emitting components from the cabling using a wiring frame. Cold air is then directed downwards to the rear of the cabinet and then to the front and up again. This creates a cool zone to the rear, where most of the cabling is located. A permanent circulation of air is generated between the warmer wiring at the front and the cooler wiring at the back. An Audi engine factory in Hungary was recently used as a testbed to compare the traditional and alternative cabinet cabling technologies. The plant, in Györ, includes automated production lines that press valve seat rings and valve guides into the cylinder heads of V6 Otto engines. The test involved two of the site’s production systems, each of which use four control cabinets with the same construction and power supplies. The cabinets were each 2000mm high and 600mm deep. Three cabinets in each systemwere 1,200mmwide, while the fourth was 600mm. For the test, one of the four cabinets in each systemwas monitored. The first cabinet was equipped with a conventional mounting plate and was cooled using an air-conditioning systemwith a 1.5kW heat loss. In the second cabinet, the mounted components were separated from the wiring using a wiring frame – Lütze’s AirStream system. The use of trunking that might impair airflows was also avoided in this cabinet, which was cooled using 1.45kW heat exchangers. The relative power losses of the two cooling systems was a minor factor because, in both cases, the cold air came from the roof. Instead, the study focused on verifying the effect of guided air inside the control cabinet. In the Tests at an Audi factory have shown that an alternative form of cabinet wiring can cut internal temperatures by about four degrees, potentially extending the lives of components inside the cabinets. As Lütze’s cabinets product manager, Michael Bautz, reports, the reduction was greatest at hotspots that are critical for many components. Fig 1: A look inside the control cabinets used in the Audi tests. The photo on the left shows the cabinet using the wiring frame, while that on the left shows the cabinet with conventional mounting plates. sales@electric-motors.online 02476 980833 www.electric-motors.online DON’T KEEP ON GOING ROUND AND ROUND Contact EMO for all your Electric Motor and Automation related needs Sales, Service, Maintenance and Mechanical Engineering Electric Motors Online is a family run business located in Nuneaton, Warwickshire. With over 30-years experience in the electric motor and automation industries we are distributors and resellers for a large number of major manufacturers. We pride ourselves on our product knowledge experience and the service that we provide – 24 hours a day, 7 days a week, 365 days a year.