Patent US5521471A successfully refreshed from Google Patents.
US5521471A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Series (or compound) motor and control circuit for adjusting effective exciting turn ratio of series field winding according to rotational speed or load current
Assignee: Individual
•
Filing: 1994-10-27
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Granted: 1996-05-28
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Expires: 2014-10-27
Abstract
Abstract A switch device is mounted between the power supply and a multi-tap series field winding in a series or compound motor. The switch is responsive to changes in rotational speed or load current in order to change the effective excitation turn ratio of the series winding.
Inventors
- 👤 Tai-Her Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:49
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/298
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
77 words
A DC motor including a series field winding having a plurality of taps and means including a switch for connecting one of the taps with an input to the motor, said switch also being connected to means for measuring an operating state of the motor and supplying a signal to the switch in order to cause the switch to switch between said taps and thereby change the effective turn ratio in response to changes in said state.
Claim 2
Dependent Claim
77 words
A DC motor including a series field winding having a plurality of taps and means including a switch for connecting one of the taps with an input to the motor, said switch also being connected to means for measuring an operating state of the motor and supplying a signal to the switch in order to cause the switch to switch between said taps and thereby change the effective turn ratio in response to changes in said state.
Claim 3
Dependent Claim
18 words
A motor as claimed in claim 1, wherein said measuring means comprises means for measuring a load current.
Claim 4
Dependent Claim
17 words
A motor as claimed in claim 1, wherein said measuring means comprises means for measuring motor speed.
Claim 5
Dependent Claim
20 words
A motor as claimed in claim 1, wherein said measuring means comprises means for measuring electromotive force in the armature.
Claim 6
Dependent Claim
30 words
A motor as claimed in claim 1, further comprising means for measuring a voltage across inputs of the motor and supplying a signal representative of said voltage to said switch.
Claim 7
Dependent Claim
20 words
A motor as claimed in claim 1, wherein said motor is a shunt motor which further comprises a shunt winding.
Claim 8
Dependent Claim
47 words
A motor as claimed in claim 1, wherein said switch is arranged to increase the effective excitation turn ratio of the series field winding upon detection of a decrease in load current, and to switch to a lower effective excitation turn ratio when the load current rises.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-05-28 | 1999-11-27 | 2000-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-05-28 | 2003-11-27 | 2004-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-05-28 | 2007-11-27 | 2008-05-28 | $7700.00 | Window Closed / Lapsed |