US4112475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D-C motor flashover protection
Assignee: General Electric Co
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Filing: 1976-12-22
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Granted: 1978-09-05
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Expires: 1996-12-22
Abstract
Abstract A method and apparatus for detecting and correcting the occurrence of flashover in a direct current electric motor. The polarity and magnitude of voltage on the field winding of the motor is continuously monitored. Detection of a sudden reversal of the polarity of the field voltage accompanied by a rapid increase in magnitude results in the generation of a flashover signal. The flashover signal is coupled to power controlling elements regulating power supplied to the motor and is effective to force removal of power from the motor. In a preferred embodiment the apparatus is disclosed in a two-motor system with two field windings serially connected such that the field voltage monitoring is accomplished on a differential basis.
Inventors
- 👤 Thomas Detlor Stitt
- 👤 Dennis Francis Williamson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:16
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/0811
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
99 words
A protection system for a direct current electric traction motor, said motor having armature and field means adapted for receiving direct current electric power from a direct current power source, said system comprising: a. regulating means interconnecting said motor current path; b. detection means connected for monitoring the polarity and magnitude of voltage on said field means, said detection means being responsive to rapid reversal of said polarity for producing a flashover signal; and c. means coupling said flashover signal to said regulating means, said regulating means being responsive to said flashover signal for interrupting said motor current path.
Claim 2
Dependent Claim
99 words
A protection system for a direct current electric traction motor, said motor having armature and field means adapted for receiving direct current electric power from a direct current power source, said system comprising: a. regulating means interconnecting said motor current path; b. detection means connected for monitoring the polarity and magnitude of voltage on said field means, said detection means being responsive to rapid reversal of said polarity for producing a flashover signal; and c. means coupling said flashover signal to said regulating means, said regulating means being responsive to said flashover signal for interrupting said motor current path.
Claim 3
Dependent Claim
71 words
The system of claim 1 wherein said regulating means comprises: a. first means connected in said motor current path for controlling the flow of current therethrough; b. second means responsive to a commanded magnitude of current for applying control signals to said first means to thereby regulate motor current to the commanded magnitude; and c. third means responsive to said flashover signal for reducing said commanded magnitude of current to zero.
Claim 4
Dependent Claim
32 words
The system of claim 2 and including electromechanical switch means interconnecting the source and the motor, said third means being connected to open said switch means in response to said flashover signal.
Claim 5
Dependent Claim
37 words
The system of claim 3 wherein said motor is connected in a separately excited arrangement, the regulating means including first means interconnecting the source and the field means and second means interconnecting the source and the armature.
Claim 6
Dependent Claim
146 words
The system of claim 4 including first and second direct current electric traction motors, the armatures of said motors being serially connected in a first current path and the field means of said motors being serially connected in a second current path, said detection means comprising: a. first and second serially connected resistors connected in parallel circuit arrangement with said field means; b. a capacitor and a primary winding of a pulse transformer serially connected between a junction intermediate said field means of said first and second motors and a junction intermediate said first and second resistors; c. a voltage comparison circuit; and a secondary winding of said pulse transformer being connected to said voltage comparison circuit whereby said flashover signal is produced at an output terminal of said comparison circuit in response to a voltage pulse on said secondary winding exceeding a first predetermined magnitude.
Claim 7
Dependent Claim
92 words
The system of claim 5 and including: a. means connected in circuit with said field means for providing a first current signal representative of the magnitude of current in said field means; b. second comparison means connected for receiving said first current signal, said second comparison means providing a second flashover signal when the rate of change of magnitude of said first current signal exceeds a second predetermined value; and c. means for combining said first and second flashover signals to provide a single flashover signal for removing excitation from said motors.
Claim 8
Dependent Claim
63 words
The system of claim 6 and including a third comparison means connected for receiving said first current signal, said third comparison means providing a third flashover signal when the magnitude of said first current signal exceeds a third predetermined magnitude, and means for combining said first, second and third flashover signals to provide a single flashover signal for removing excitation from said motors.
Claim 9
Dependent Claim
85 words
The system of claim 7 and including: a. means connected in circuit with said armatures for providing a second current signal representative of the magnitude of current in said armature; b. fourth comparison means connected for receiving said second current signal, said fourth comparison means providing a fourth flashover signal when said second current signal exceeds a fourth predetermined magnitude; and c. means for combining said first, second, third and fourth flashover signals to provide a single flashover signal for removing excitation from said motors.
Claim 10
Independent Claim
78 words
A method for detecting a flashover in a direct current electric motor having armature and field means, said method comprising the steps of: a. monitoring the polarity and magnitude of voltage on the field means; b. detecting a reversal of said polarity; c. producing a signal representative of the magnitude of said voltage during said reversal; d. comparing said signal to a predetermined reference magnitude; and e. producing a flashover signal when said signal exceeds said reference magnitude.
Claim 11
Independent Claim
78 words
A method for detecting a flashover in a direct current electric motor having armature and field means, said method comprising the steps of: a. monitoring the polarity and magnitude of voltage on the field means; b. detecting a reversal of said polarity; c. producing a signal representative of the magnitude of said voltage during said reversal; d. comparing said signal to a predetermined reference magnitude; and e. producing a flashover signal when said signal exceeds said reference magnitude.
Claim 12
Dependent Claim
32 words
A method for protecting a direct current electric motor including the method of claim 9 and the additional step of: a. removing power to the motor in response to said flashover signal.
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) | 1981-09-04 | 1982-03-06 | 1982-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-04 | 1986-03-06 | 1986-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-04 | 1990-03-06 | 1990-09-05 | $7700.00 | Window Closed / Lapsed |