by Richard Mandel

While microwave oven technology has been around since the late 1940s, it wasn't until the mid-1970s that the first viable home units came onto the market. The traditional design has been to supply 100% of power to the magnetron, cycling it on and off to create variations in "power." For instance, a microwave operating at 60% power is on for 60% of the time and idle 40% of the time. While the power components for this are fairly basic, the cycling does not provide for the most even defrosting and cooking of foods, limiting the microwave for most consumers as a large device for reheating leftovers and making 4-minute popcorn. The Panasonic Consumer Electronics Co., Secaucus, NJ, a division of Matsushita Electric Corp. of America, introduced this year their Inverter line of ovens that employ a power circuit actually delivering a steady 60% of power (or whatever the user has selected). The company literature says that the development allows even delicate foods to simmer without overcooking the edges and surface. Another control, labeled "Inverter Turbo Defrost," applies a sequence of low power microwaves in a pattern Panasonic claims is based on chaos theory. The regular and irregular patterns provide even defrosting of frozen foods up to 49% faster than non-inverter technology. Circle 400 - Panasonic or connect directly to their website at http://www.OneRS.net/103df-400

The technology of linear motors has made inroads into consumer products. The above-mentioned Panasonic uses linear technology in a line of shavers, moving the cutter at a rate of 13,000 cycles per minute. And LG Electronics, Englewood Cliffs, NJ, a Korean manufacturer of consumer appliances and computer equipment, has developed a linear refrigerator compressor. The technology eliminates friction losses through the crankshaft, connecting rod and journal bearing of an ordinary reciprocating compressor. An electronic controller, based on a simple and inexpensive Triac circuit, can vary the stroke to create a zero clearance volume. The plus side is a compressor that is 20-40% higher in efficiency over existing designs. To minimize performance loss, the core of the LG motor was laminated in a radial direction, and the moving magnet design has no end-coil or rotor bar. The helical resonant spring employed has a very low side force during compression to prevent wear problems between the piston and cylinder. A disk valve and coil spring combination are used in place of conventional reed valves for the discharge valve system, which reduces over-compression loss owing to its larger flow area and provides axial single-direction refrigerant flow. Circle 401 - LG Electronics USA Inc, or connect directly to their websiteat http://www.OneRS.net/103df-401