General Information
Introduction Magnetics Molypermalloy Powder (MPP) cores are distributed air gap toroidal cores made from a 81% nickel, 17% iron, and 2% molybdenum alloy powder for the lowest core losses of any powder core material. MPP cores (and all powder cores) exhibit soft saturation, which is a significant design advantage compared with gapped ferrites. Also, unlike ferrites, the MPP saturation curve does not need to be derated with increasing device temperature. MPP cores possess many outstanding magnetic characteristics, such as high resistivity, low hysteresis and eddy current losses, excellent inductance stability after high DC magnetization or under high DC bias conditions and minimal inductance shift under high AC excitation. MPP THINZ®, or washer cores, put the premium performance of Magnetics’ superior MPP material into robust, low height toroid form, for low profile inductors. With MPP THINZ, exact permeability and height are easily adjusted to result in the optimum design for each application. Magnetics High Flux powder cores are distributed air gap toroidal cores made from a 50% nickel - 50% iron alloy powder for the highest biasing capability of any powder core material. High Flux cores have advantages that result in superior performance in certain applications involving high power, high DC bias, or high AC excitation amplitude. The High Flux alloy has saturation flux density that is twice that of MPP alloy, and three times or more than that of ferrite. As a consequence, High Flux cores can support significantly more DC Bias current or AC flux density. High Flux offers much lower core losses and superior DC bias compared with powdered iron cores. High Flux cores offer lower core losses and similar DC bias compared with XFLUX cores. Frequently, High Flux allows the designer to reduce the size of an inductive component compared with MPP, powdered iron, or ferrite.
Magnetics Kool Mµ® powder cores are distributed air gap cores made from a ferrous alloy powder for low losses at elevated frequencies. The near zero magnetostriction alloy makes Kool Mµ ideal for eliminating audible frequency noise in filter inductors. In high frequency applications, core losses of powdered iron, for instance, can be a major factor in contributing to undesirable temperature rises. Kool Mµ cores are superior because their losses are significantly less, resulting in lower temperature rises. Kool Mµ cores generally offer a reduction in core size, or an improvement in efficiency, compared with powdered iron cores. Inductors built with Kool Mµ cores do not have several of the disadvantages that are inherent with gapped ferrite cores: 1. Ferrite saturation flux density is 0.5T or less, which is less than half of the flux density of Kool Mµ alloy. This results in much less energy storage possible in the same volume with ferrite. 2. Moreover, saturation flux density in ferrites is reduced significantly at elevated temperatures, but in Kool Mµ it is not. 3. Ferrites exhibit sharp saturation, and thus risk complete collapse of inductance above a certain safe current level. Kool Mµ’s saturation is soft, allowing for safe design to much higher currents. 4. Fringing losses at the discrete air gap in a ferrite inductor can be disastrous, a problem that is completely absent with Kool Mµ. Kool Mµ is available in a variety of core types, for maximum flexibility. Toroids offer compact size and self-shielding. E cores and U cores afford lower cost of winding, use of foil inductors, and ease of fixturing. Very large cores and structures are available to support very high current applications. These include toroids and racetrack shapes up to 102 mm, 133 mm and 165 mm; jumbo E cores; stacked shapes; and blocks. Magnetics XFLUX® distributed air gap cores are made from 6.5% silicon iron powder. A true high temperature material, with no thermal aging, XFLUX offers lower losses than powdered iron cores and superior DC bias performance. The soft saturation of XFLUX material offers an advantage over ferrite cores. XFLUX cores are ideal for low and medium frequency chokes where inductance at peak load is critical.
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