Electrostatic motor having fluid management features
An example electrostatic machine includes a number of stator plates, each having a stator electrode and rotationally fixed to a housing, a shaft at least partially defined within the housing and configured to rotate about an axis, and a number of rotor plates, each having a rotor electrode and rotational fixed to the shaft. The electrostatic machine includes a dielectric fluid disposed in the housing, and that fills a gap between the stator plates and the rotor plates. The electrostatic machine includes a seal associated with the shaft, where the seal includes a material compatible with the dielectric fluid.
1. An electrostatic machine comprising:
a plurality of stator plates, each comprising a stator electrode, and rotationally fixed to a housing;
a shaft at least partially defined within the housing and configured to rotate about an axis;
a plurality of rotor plates, each comprising a rotor electrode, and rotationally fixed to the shaft;
a dielectric fluid disposed in the housing, and that fills a gap between the plurality of stator plates and the plurality of rotor plates;
at least one seal associated with the shaft; and
wherein the at least one seal comprises a material compatible with the dielectric fluid at an operating temperature of the electrostatic machine.
2. The electrostatic machine of claim 1 , wherein the at least one seal comprises a first material encapsulated in a second material, wherein the second material is compatible with the dielectric fluid.
3. The electrostatic machine of claim 1 , wherein the at least one seal comprises a fluorinated ethylene propylene.
4. The electrostatic machine of claim 1 , wherein the at least one seal comprises a virgin polytetrafluoroethylene.
5. The electrostatic machine of claim 1 , wherein the at least one seal comprises polytetrafluoroethylene/polyetherimide.
6. The electrostatic machine of claim 1 , wherein the at least one seal comprises a high density terpolymer comprising ethylene, tetrafluoroethylene, and perfluoromethyl vinyl ether monomers.
7. The electrostatic machine of claim 1 , wherein the at least one seal comprises a perfluoroelastomer.
8. The electrostatic machine of claim 1 , further comprising a second seal associated with an electrical coupling between an exciter fluidly isolated from the dielectric fluid and at least one of the stator plates or the rotor plates, and wherein the second seal comprises a material compatible with the dielectric fluid.
9. The electrostatic machine of claim 8 , wherein the second seal comprises a cured potting material.
10. The electrostatic machine of claim 1 , wherein the at least one seal comprises a liquid seal.
11. The electrostatic machine of claim 10 , wherein the liquid seal comprises a ferrofluid.
12. The electrostatic machine of claim 1 ,
wherein the dielectric fluid comprises a dielectric fluid base and at least one additive.
13. The electrostatic machine of claim 12 , wherein the dielectric fluid comprises at least one base fluid selected from the fluids consisting of: a ketone, an ester, or a carbonate.
14. The electrostatic machine of claim 12 , wherein the dielectric fluid comprises at least one base fluid selected from the fluids consisting of: isoamyl isovalerate, hexyl isobutyrate, diethyl ethyl malonate, a malonate, delta-nonalactone, or a lactone.
15. The electrostatic machine of claim 12 , wherein the dielectric fluid comprises at least one base fluid selected from the fluids consisting of: a propylene carbonate-based fluid composition an oxalate an amide an imide or a lactam.
16. The electrostatic machine of claim 12 , wherein the at least one additive comprises a free radical scavenger.
17. The electrostatic machine of claim 16 , wherein the free radical scavenger comprises at least one compound selected from among: butylated hydroxytoluene, butylated hydroxyanisole, tertiary-butylhydroquinone, gallate, or a phenolic antioxidant.
18. The electrostatic machine of claim 12 , wherein the at least one additive comprises a contamination scavenger.
19. The electrostatic machine of claim 18 , wherein the contamination scavenger comprises at least one of an organo-metallic compound, trimethyl (phenyl) tin, or a bismuth organo-metallic.
20. The electrostatic machine of claim 12 , wherein the at least one additive comprises barium titanate.
21. The electrostatic machine of claim 12 , wherein the at least one additive comprises a water scavenger.
22. The electrostatic machine of claim 21 , wherein the water scavenger comprises at least one compound selected from among: an oxazolidine, a monomeric isocyanate, and an alkoxysilane.
23. The electrostatic machine of claim 21 , wherein the water scavenger comprises at least one compound selected from among: CaCl, CaSO 4 , Copper (II) Sulfate, LiAlH 4 , MgSO 4 , phosphorous pentoxide, potassium carbonate, a silica gel, a monomeric isocyanate, and an alkoxysilane.
24. The electrostatic machine of claim 21 , wherein the water scavenger comprises a molecular sieve provided in fluid contact with the dielectric fluid.
25. The electrostatic machine of claim 21 , wherein the water scavenger is provided as an additive in fluid contact with the dielectric fluid.
26. The electrostatic machine of claim 12 , wherein the at least one additive comprises a coated metal oxide.
27. The electrostatic machine of claim 12 , wherein each of the at least one additive is present in an amount between 1 ppm and 1% by weight.
28. The electrostatic machine of claim 12 , wherein the at least one additive comprises a coated metal oxide.
29. An electrostatic machine comprising:
a plurality of stator plates, each comprising a stator electrode, and rotationally fixed to a housing;
a shaft at least partially defined within the housing and configured to rotate about an axis;
a plurality of rotor plates, each comprising a rotor electrode, and rotationally fixed to the shaft;
a dielectric fluid disposed in the housing, and that fills a gap between the plurality of stator plates and the plurality of rotor plates;
at least one seal associated with the shaft; and
wherein the at least one seal comprises a first material encapsulated in a second material, wherein the second material is compatible with the dielectric fluid.
30. The electrostatic machine of claim 29 , wherein the at least one seal comprises a fluorinated ethylene propylene.
31. The electrostatic machine of claim 29 , wherein the at least one seal comprises a virgin polytetrafluoroethylene.
32. The electrostatic machine of claim 29 , wherein the at least one seal comprises polytetrafluoroethylene/polyetherimide.
33. The electrostatic machine of claim 29 , wherein the at least one seal comprises a high density terpolymer comprising ethylene, tetrafluoroethylene, and perfluoromethyl vinyl ether monomers.
34. The electrostatic machine of claim 29 , wherein the at least one seal comprises a perfluoroelastomer.
35. The electrostatic machine of claim 29 , further comprising a second seal associated with an electrical coupling between an exciter fluidly isolated from the dielectric fluid and at least one of the stator plates or the rotor plates, and wherein the second seal comprises a material compatible with the dielectric fluid.
36. The electrostatic machine of claim 35 , wherein the second seal comprises a cured potting material.
37. The electrostatic machine of claim 29 , wherein the at least one seal comprises a liquid seal.
38. The electrostatic machine of claim 37 , wherein the liquid seal comprises a ferrofluid.
39. An electrostatic machine comprising:
a plurality of stator plates, each comprising a stator electrode, and rotationally fixed to a housing;
a shaft at least partially defined within the housing and configured to rotate about an axis;
a plurality of rotor plates, each comprising a rotor electrode, and rotationally fixed to the shaft;
a dielectric fluid disposed in the housing, and that fills a gap between the plurality of stator plates and the plurality of rotor plates;
at least one seal associated with the shaft;
wherein the at least one seal comprises a material compatible with the dielectric fluid; and
a second seal associated with an electrical coupling between an exciter fluidly isolated from the dielectric fluid and at least one of the stator plates or the rotor plates, and wherein the second seal comprises a material compatible with the dielectric fluid.
40. The electrostatic machine of claim 39 , wherein the at least one seal comprises a fluorinated ethylene propylene.
41. The electrostatic machine of claim 39 , wherein the at least one seal comprises a virgin polytetrafluoroethylene.
42. The electrostatic machine of claim 39 , wherein the at least one seal comprises polytetrafluoroethylene/polyetherimide.
43. The electrostatic machine of claim 39 , wherein the at least one seal comprises a high density terpolymer comprising ethylene, tetrafluoroethylene, and perfluoromethyl vinyl ether monomers.
44. The electrostatic machine of claim 39 , wherein the at least one seal comprises a perfluoroelastomer.
45. The electrostatic machine of claim 39 , wherein the second seal comprises a cured potting material.
46. The electrostatic machine of claim 39 , wherein the at least one seal comprises a liquid seal.
47. The electrostatic machine of claim 46 , wherein the liquid seal comprises a ferrofluid.