Patent US3875484A successfully refreshed from Google Patents.
US3875484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Travelling field electric motor with improved stator
Assignee: British Nuclear Fuels Ltd
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Filing: 1973-12-28
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Granted: 1975-04-01
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Expires: 1993-12-28
Abstract
Abstract An alternating current electric motor has a stator comprising an inductive winding in association with capacitance to ensure that the winding has the characteristics of a transmission line. The rotor of the motor may be of the induction, hysteresis or reluctance type. In one form, the winding of the stator is toroidal, such as gramme ring type, with shunt capacitors at fixed intervals along its length. In an alternative form, a linear motor has a solenoid type stator winding with shunt capacitors at fixed intervals. The invention enables speed to be closely defined without being essentially related to supply frequency.
Inventors
- 👤 John Llewellyn Williams
- 👤 Ralph James Harte
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:05
CPC Classifications
H; H02; H02K; H02K17/00; H02K17/02; H02K17/04; H02K11/00; H02K11/0094; H02K11/20; H02K11/30; H02K11/33; H02K41/00; H02K41/02; H02K99/00; H02K99/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
189 words
In an electric drive system including an alternating current electric motor having a stator, a stator core and a rotor arranged to be driven by energization of the stator winding from a single-phase alternating current supply, a stator arrangement comprising an inductive stator winding having two ends and an even number of tapping points at substantially equi-spaced intervals along its length, the same even number of capacitors associated with the inductive stator winding, a common connector, means for connecting each capacitor in parallel with a section of the winding between a respective tapping point and the common connector, and first and second electric current supply terminals, said first terminal being connected to one end of the inductive stator winding and said second terminal being connected to the common connector; the inductive winding, the capacitors, and the frequency of the supply being so arranged and matched that, in operation, the wavelength of the winding current is equal to an even multiple of the said sections such that a travelling magnetic field is set up in the stator and the magnetic intensities at the two ends of the winding are equal.
Claim 2
Dependent Claim
189 words
In an electric drive system including an alternating current electric motor having a stator, a stator core and a rotor arranged to be driven by energization of the stator winding from a single-phase alternating current supply, a stator arrangement comprising an inductive stator winding having two ends and an even number of tapping points at substantially equi-spaced intervals along its length, the same even number of capacitors associated with the inductive stator winding, a common connector, means for connecting each capacitor in parallel with a section of the winding between a respective tapping point and the common connector, and first and second electric current supply terminals, said first terminal being connected to one end of the inductive stator winding and said second terminal being connected to the common connector; the inductive winding, the capacitors, and the frequency of the supply being so arranged and matched that, in operation, the wavelength of the winding current is equal to an even multiple of the said sections such that a travelling magnetic field is set up in the stator and the magnetic intensities at the two ends of the winding are equal.
Claim 3
Dependent Claim
19 words
An electric drive system as claimed in claim 1, wherein the inductive stator winding comprises a gramme ring winding.
Claim 4
Dependent Claim
32 words
An electric drive system as claimed in claim 1, wherein the capacitor connected to the tapping point farthest from the input terminal to the winding is replaced by a closed circuit connection.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |