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| Which frequency & single or large Magnetrons |
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What frequency should I use? Single or multiple magnetrons? Both of the above questions are sometimes related. Some facts about each approach are listed below. • Magnetron efficiencies are between 50-72% for 2.45GHz compared to 80 to 87 % for high power 922 or 915MHz. • The lower the frequency the great the penetration depth into a material. • Field uniformity is usually better when multiple magnetrons are used. • There are no 915 or 922MHz magnetrons less than 5kW. • At 2.45GHz magnetron range in power from 1kW to 30kW, at 915MHz the range is from 5kW to 100kW. • Different frequencies can initiate different energy transfer mechanisms within the material being heated, which may impact on reaction thermodynamics or product quality. • Applicator dimensions and complexity would be much greater using multiple magnetrons. • The larger the applicator greater will be the thermal losses and reduced microwave efficiencies. A larger applicator would be required if multiple magnetrons were used. • In multiple magnetron installations, magnetron life is reduced due to cross coupling of power between each. • Multiple magnetron systems provide a high degree of redundancy. • Multiple low power magnetron generators are simple in design allowing any technician microwave technician to repair them. • In some situations the replacement cost of low power magnetrons
per kW can be higher than that of high power magnetrons. |
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