1-10. (canceled)
11. A permanent magnet synchronous motor, comprising:
a rotor having a rotor core in which plural NdFe rare-earth segment permanent magnets are provided at an outer periphery, supported so as to rotate freely; and
a stator having stator windings and a stator core, provided at the outside of the rotor through a gap,
wherein, when a gap length between the outer periphery of the permanent magnet and an inner periphery of the stator core is \u201cL\u201d (mm) and a thickness of the central portion of the permanent magnet in the motor rotation direction is \u201ct\u201d (mm), the gap length \u201cL\u201d and the thickness \u201ct\u201d are set in a range of
L=0.6 to 0.7 mm,t(t+L)=0.77 to 0.85.
wherein the thickness of both end portions of the permanent magnet \u201ce\u201d (mm) is set in a range of 0.4\u2266et\u22660.70
wherein, when the number of poles of the permanent magnets is \u201cP\u201d, and the number of slots of the stator is \u201cN\u201d, the number of poles \u201cP\u201d and the number of slots \u201cN\u201d are set so that:
P:N=5n:6n or 7n:6n (\u201cn\u201d is an integer equal to 2 or more) and
wherein remanent flux density Br of the permanent magnet is set in a range of
Br\u22671.2T.
12. The permanent magnet synchronous motor according to claim 11,
wherein the number of poles of the permanent magnets is set to 10, and the number of slots of the stator is set to 12.
13. The permanent magnet synchronous motor according to claim 11,
wherein the stator core has a configuration in which laminated steel sheets overlap one another at contact portions of split cores as well as are coupled by circular projections provided at overlapped portions to rotate one another.
14. The permanent magnet synchronous motor according to claim 13,
wherein rotation lamination is performed to the stator core.
15. The permanent magnet synchronous motor according to claim 11,
wherein the stator core is configured by a coupled core in which plural core portions are coupled in a belt shape.
16. The permanent magnet synchronous motor according to claim 11,
wherein the motor is for an electric power steering system.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of treating a subterranean formation in a well comprising:
a. providing an aqueous medium comprised at least in part of oilfield produced water comprising at least enzymes, microorganisms or combinations thereof;
b. contacting the aqueous medium with a zirconium compound to at least inactivate the enzymes, the microorganisms or combinations thereof;
c. energizing the combination of the aqueous medium and the inorganic zirconium compound with a gas;
d. introducing the combination in to the well; and
e. allowing the combination to contact the formation.
2. The method of claim 1 wherein the aqueous medium is oilfield produced water exclusively.
3. The method of claim 1 wherein the zirconium compound is an organo-zirconium compound.
4. The method of claim 1, further comprising:
introducing proppant in to the well; whereby the combination of the aqueous medium and zirconium compound allows better transport capability of the proppant in to the formation compared to the aqueous medium alone.
5. The method of claim 1, wherein the gas is carbon dioxide, nitrogen, air, or combined.
6. The method of claim 3 wherein the organo-zirconium compound is selected from the group consisting of zirconium acetate, zirconyl acetate, zirconium acetylacetonate, zirconium glycolate, zirconium lactate, zirconium naphthenate, sodium zirconium lactate, triethanolamine zirconium, zirconium propionate, hydrates thereof and combinations thereof.
7. The method of claim 1 wherein the zirconium compound is an inorganic zirconium compound.
8. The method of claim 7 wherein the inorganic zirconium compound is selected from the group consisting of zirconium nitrate, zirconyl chloride, zirconium phosphate, zirconium potassium chloride, zirconium potassium fluoride, zirconium potassium sulfate, zirconium pyrophosphate, zirconium sulfate, zirconium tetrachloride, zirconium tetrafluoride, zirconium tetrabromide, zirconium tetraiodide, zirconyl carbonate, zirconyl hydroxynitrate, zirconyl sulfate, zirconium complexed with amino acids, zirconium complexed with phosphonic acids, hydrates thereof and combinations thereof.