# US 2021/0242802 A1 · Electrostatic motor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242802 A1 - Document ID: US20210242802A1 - Status: Published application - Kind: A1 - Application number: 17/234,494 - Filed: 2021-04-19 - Published: 2021-08-05 - Earliest claimed: 2020-01-03 - Assignees: C-Motive Technologies, Inc. - Applicants: C-Motive Technologies, Inc. - Inventors: Justin Kyle Reed; Ryan Knippel; William D. Butrymowicz; Graham T. Reitz; Baoyun Ge; Daniel Colin Ludois; Kevin Frankforter - Web page: https://patentgrep.com/patent/US20210242802A1 ## CPC - H02N 1/006: {of the gap-closing type (H02N1/004 takes precedence)} - H02N 1/002: {Electrostatic motors} - H02N 1/004: {in which a body is moved along a path due to interaction with an electric field travelling along the path} - H02N 2/12: Constructional details - H02N 2/14: Drive circuits; Control arrangements {or methods} - Y10T 29/49009: Dynamoelectric machine - Y10T 29/5313: Means to assemble electrical device - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An example electrostatic machine includes a shaft configured to rotate about an axis; a rotor electrode and a stator electrode separated by a gap and forming a capacitor, wherein the rotor electrode is rotationally coupled to the shaft; wherein at least a portion of an exposed surface of the rotor electrode comprises a polished surface, and wherein at least a portion of an exposed surface of the stator electrode comprises a polished surface; a housing configured to enclose the rotor electrode, the stator electrode, and at least a portion of the shaft, wherein the stator electrode is rotationally coupled to the housing; and a dielectric fluid disposed between the rotor electrode and the stator electrode. ## Claims ### Claim 1 An electrostatic machine, comprising: a shaft configured to rotate about an axis; a rotor electrode and a stator electrode separated by a gap and forming a capacitor, wherein the rotor electrode is rotationally coupled to the shaft; wherein at least a portion of an exposed surface of the rotor electrode comprises a polished surface, and wherein at least a portion of an exposed surface of the stator electrode comprises a polished surface; a housing configured to enclose the rotor electrode, the stator electrode, and at least a portion of the shaft, wherein the stator electrode is rotationally coupled to the housing; and a dielectric fluid disposed between the rotor electrode and the stator electrode. ### Claim 2 (depends on 1) The electrostatic machine of claim 1, wherein the at least a portion of the exposed surface of each of the rotor electrode and the stator electrode comprises a closest portion of the respective electrodes to the gap. ### Claim 3 (depends on 1) The electrostatic machine of claim 1, wherein the at least a portion of the exposed surface of each of the rotor electrode and the stator electrode comprises a geometric portion of the respective electrodes facing the gap. ### Claim 4 (depends on 1) The electrostatic machine of claim 1, wherein the rotor electrode comprises a surface progression between a first portion facing the gap and a second portion engaging a rotor plate, wherein the surface progression comprises a curved region. ### Claim 5 (depends on 4) The electrostatic machine of claim 4, wherein the curved region exceeds a minimum radius of curvature throughout the surface progression. ### Claim 6 (depends on 1) The electrostatic machine of claim 1, wherein the stator electrode comprises a surface progression between a first portion facing the gap and a second portion engaging a stator plate, wherein the surface progression comprises a curved region. ### Claim 7 (depends on 6) The electrostatic machine of claim 6, wherein the curved region exceeds a minimum radius of curvature throughout the surface progression. ### Claim 8 (depends on 1) The electrostatic machine of claim 1, wherein the housing comprises an interior surface exposed to the dielectric fluid, and wherein the interior surface comprises a polished housing surface. ### Claim 9 (depends on 1) The electrostatic machine of claim 1, wherein the polished surface of at least one of the at least a portion of the exposed surface of the rotor electrode or the stator electrode comprises a roughness of less than Ra=10 microns. ### Claim 10 (depends on 1) The electrostatic machine of claim 1, wherein the polished surface of at least one of the at least a portion of the exposed surface of the rotor electrode or the stator electrode comprises a roughness not exceeding an ISO N10 roughness grade. ### Claim 11 (depends on 1) The electrostatic machine of claim 1, wherein the polished surface of at least one of the at least a portion of the exposed surface of the rotor electrode or the stator electrode comprises a roughness not exceeding an ISO N9 roughness grade. ### Claim 12 (depends on 1) The electrostatic machine of claim 1, wherein the polished surface of at least one of the at least a portion of the exposed surface of the rotor electrode or the stator electrode comprises a first portion having a first roughness description, and a second portion having a second roughness description. ### Claim 13 (depends on 12) The electrostatic machine of claim 12, wherein the first portion comprises a lower roughness than the second portion, and wherein the first portion is geometrically closer to the other one of the at least a portion of the exposed surface of the rotor electrode or the stator electrode. ### Claim 14 (depends on 1) The electrostatic machine of claim 1, wherein the housing comprises an interior surface exposed to the dielectric fluid, and wherein the interior surface comprises at least one of a hardened surface or a coated surface. ### Claim 15 (depends on 1) The electrostatic machine of claim 1, wherein at least one of the rotor electrode or the stator electrode further comprise a surface treatment comprising a deposition of a space charge injection manager on at least a portion of the rotor electrode or the stator electrode. ### Claim 16 (depends on 15) The electrostatic machine of claim 15, wherein the space charge injection manager comprises at least one material selected from the materials consisting of: Cu, Ag, Au, Rh, Ni, Pt, Pd, Os, W, Pb, Ti, Al, stainless steel, alloys of any of the foregoing, or a semi-conducting polymer. ### Claim 17 (depends on 16) The electrostatic machine of claim 16, wherein the space charge injection manager promotes a uniform charge distribution of the at least one of the rotor electrode or the stator electrode. ### Claim 18 (depends on 16) The electrostatic machine of claim 16, wherein the space charge injection manager inhibits an introduction of charge carriers from the at least one of the rotor electrode or the stator electrode into the dielectric fluid. ### Claim 19 (depends on 1) The electrostatic machine of claim 1, further comprising a rotor plate, wherein the rotor electrode is mounted on the rotor plate, and wherein a surface of the rotor plate is polished. ### Claim 20 (depends on 1) The electrostatic machine of claim 1, further comprising a rotor plate, wherein the rotor electrode is mounted on the rotor plate, and wherein the rotor plate comprises a surface treatment comprising a deposition of a conductive material configured to promote uniform charge distribution of the rotor electrode at a high voltage operating condition of the electrostatic machine. ### Claim 21 (depends on 1) The electrostatic machine of claim 1, further comprising a stator plate, wherein the stator electrode is mounted on the stator plate, and wherein a surface of the stator plate is polished. ### Claim 22 (depends on 1) The electrostatic machine of claim 1, further comprising a stator plate, wherein the stator electrode is mounted on the stator plate, and wherein the stator plate comprises a surface treatment comprising a deposition of conductive material configured to promote uniform charge distribution of the stator electrode at a high voltage operating condition of the electrostatic machine. ### Claim 23 (depends on 1) The electrostatic machine of claim 1, wherein the rotor electrode comprises a positive electrode comprising a surface treatment comprising a deposition of a space charge injection manager on at least a portion of the rotor electrode. ### Claim 24 (depends on 23) The electrostatic machine of claim 23, wherein the space charge injection manager comprises at least one material selected from the materials consisting of: Cu, Ag, Au, Rh, Ni, Pt, Pd, Os, W, Pb, Ti, Al, stainless steel, alloys of any of the foregoing, or a semi-conducting polymer. ### Claim 25 (depends on 24) The electrostatic machine of claim 24, further comprising a second rotor electrode comprising a surface treatment of at least a portion of an exposed surface of the second rotor electrode, wherein the second rotor electrode comprises a negative electrode, and wherein the surface treatment of the second rotor electrode comprises a deposition of a second space charge injection manager on at least a portion of the second rotor electrode, and wherein the second space charge injection manager comprises a distinct material from the at least one material of the space charge injection manager.