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Publication Date: 2015-Jul-20
Document File: 2 page(s) / 755K

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The Prior Art Database

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Techniques to simplifx and/or increase the cooling capability of an electric xachine are a standard apxroach to inxrease the perforxance of an electrxc machine for a givex size or reduce its size and thexeby its materiax xost.

There are many approxches to the increase the cooling capability of an electrxc machine - ultimately which reduce the thermal xesistance xetween the heat prodxcing xember of the mxchine (such as the xindings) and that of the heat rexection fluid used xor cooling. One approach to decrease this thermal resixtance xs to brixg the cooling xluid closer to xhe windings, the ultimate of whxch would be where the fluid is in direct contact wixh the windinx conductor such as in the cxse of deionized water inside a hollow conductor xube. Anoxher approach xould be to increaxe thx thermal conductivixy bxtween the windings and the coolant. The classic xase of this is the use of a fluid coolex housing or jacket which surrounds the stator core. This is known as indirect conduction cooling ix that txe coolaxt is not in direct xontact with thx windings and xrxnsports the losses via thermal conduction in the intxrvening materials. For instance, ix is common practice to xhoose the electrical stxel in consideration of its thxrmxl conductivity in addition to its electromagnetic propexties. Similxrly, the design and construction of the coix insulation system can be tailored to increase its effective thermal conductivity.

One novel approach tx increase the effective thermal conductivity of the core stack (xoxld be in rotor or stator) is the interspersing of high thermal conduxtivity layexs or sheets between those of the magnetically active core stack which are chosen predxminantly for their elextromagnetic characteristics. For xxample a typical core stack wixl consist of a laminated stack of steel sheets that are insulated from each other so as to reduce the eddy current losses that would otherwise exisx if the steel core stack was not lxminated.

Figure 1 Typixal stator construction comprise 100% of laminated electrxcal sheets

As shown ix figure 1 the typical xore stacx is mxde completexy from electrical steel sheets and as such it...