International Appliance Manufacturing 2008 - (Page 73) A piggy-back plug from Volex. This 3-pole right-angled connector is also available as a straight connector. Photo: Volex While suppliers want to make it more difficult for a plug to disconnect accidentally, they also want to make it easier to disconnect intentionally, be that from a tight fitting wall outlet or a cramped power strip. Some plugs today are fitted with levers, which are sometimes called pull-tabs, that push the plugs from the outlet as it is unplugged. “With these easy pull applications, you don’t have to yank the cord out the wall and out of the outlet,” says Xavier Carbonel, marketing director for Quail. Volex’s Foreman also suggests that design- ers that may face potential side-to-side force may choose a plug with a bigger face to reduce the force exerted on the blades. The company also offers what it calls the Pivot Plug (PH772), which is often used in vacuum-cleaner applications. The Pivot Plug has wings on either side that restrict the lateral angling of the plug as it is pulled from the outlet, which minimizes bending of the plug blades. High and dry Bent blades are not the only hazards that a plug may face in the field. Some plugs maybe subjected to moisture, and for those applications there are products rated for ingress protection (IP). At Oskaloosa, Iowa-based Interpower Corp., for instance, the company offers pin and sleeve devices that are IP 67 rated. An IP rating relates to the dust and moisture protection that it offers. The ‘6’ refers to dust and other particulates and is the IEC’s highest rating. The ‘7’ means that the product is protected against temporary immersion in water and other liquids. A lid on a socket protects the ingress, and also locks the plug in place. For Interpower, these IP products are found on their high-powered pin and sleeve products. While in North America, the most common plug is the NEMA 5-15P, sometimes that is not adequate to the application. Some of Interpower’s products are rated to 415 VAC and 125 A for international applications and up to 480 VAC and 180 A for North American applications and the plugs include singlephase and three-phase systems. Applications for high-powered products vary greatly, says Ralph Bright, marketing manager at Interpower. One application where they are often found is in fast food restaurants where commercial appliances such as ovens and dishwashers require high voltage and amperage ratings. In these kitchens, moisture and chemicals, as well as high temperatures, can be a problem that IP rated pins and sleeves can solve. These products conform to IEC 60309, a standard that was designed to standardize high-powered products around the world. It defines a family of connectors that can be used for domestic and international markets. Much as NEMA has a standardized system of blade and pin configurations, the IEC has developed “clock” and color keys (see Fig. 1 and Fig. 2) to ensure polarity and avoid “mismating” connectors, Bright says. “They don’t want you to mix and match plugs,” he adds, “so you are not trying to pull 230 volts and 20 amps out of something that can only handle 120 volts and 15 amps. “ Fig 2. This clock system helps ensure polarity and “mismating” of connectors. Source: Interpower Corp. This straight plug for the European market complies with the IEC 608841 standard, which means it can be used for household and similar purposes. Photo: Volex 73 International Appliance Manufacturing 2008
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