Patent US3673481A successfully refreshed from Google Patents.
US3673481A
Expired / Lapsed
US
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Dynamic braking for universal motors
Assignee: Prestolite Electric Inc
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Filing: 1970-05-20
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Granted: 1972-06-27
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Expires: 1990-05-20
Abstract
Abstract A dynamic braking system for universal electric motors operating on alternating current is disclosed which utilizes the discharge of a condenser to momentarily energize the series field of the motor after the power circuit to the motor is broken and the field connected accross the terminals of the rotating armature to initiate dynamically braking of the armature to bring it to a stop within a few revolutions.
Inventors
- 👤 James T Hardin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:16
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/06; H02P3/18; H02P3/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
In a universal motor having a commutator and a field coil adapted for operation from a source of alternating current, means for dynamically braking the armature of the motor comprising a condenser and a rectifier and switching means, said switching means in a ''''run'''' position, connecting the field coil in series with the armature across the source of alternating current and the condenser and rectifier Across the source of alternating current, and a second ''''stop'''' position of the switching means, connecting the field and the rectifier across the armature and the condenser across the field, whereby the condenser is charged to peak line voltage of the source of alternating current during the ''''run'''' position, and discharged as a pulse across the field in the ''''stop'''' position to dynamically brake the armature to a standstill.
Claim 2
Dependent Claim
134 words
In a universal motor having a commutator and a field coil adapted for operation from a source of alternating current, means for dynamically braking the armature of the motor comprising a condenser and a rectifier and switching means, said switching means in a ''''run'''' position, connecting the field coil in series with the armature across the source of alternating current and the condenser and rectifier Across the source of alternating current, and a second ''''stop'''' position of the switching means, connecting the field and the rectifier across the armature and the condenser across the field, whereby the condenser is charged to peak line voltage of the source of alternating current during the ''''run'''' position, and discharged as a pulse across the field in the ''''stop'''' position to dynamically brake the armature to a standstill.
Claim 3
Dependent Claim
41 words
The connections for the universal motor of claim 1 further characterized by the polarities of the condenser and the rectifier being such that the condenser is discharged only through the field circuit when the switching means is in the ''''stop'''' position.
Claim 4
Dependent Claim
17 words
The device defined in claim 1 further characterized by the switching means being a double-pole, double-throw switch.
Claim 5
Independent Claim
129 words
The method of dynamically braking a universal motor having a armature with a commutator and a series field adapted to be energized from a source of alternating current, comprising connecting the armature in series with the field for normal operation with a condenser and a rectifier connected across the source of alternating current, thereafter disconnecting the field from the series relation with the rotating armature and connecting the field in parallel with the armature and in series with the rectifier to act as an electrical load on the armature, while connecting the charged condenser across the field to discharge the condenser as a pulse through the field to create an initial excitation for the field to initiate dynamic braking of the rotating armature to bring it to a standstill.
Claim 6
Independent Claim
129 words
The method of dynamically braking a universal motor having a armature with a commutator and a series field adapted to be energized from a source of alternating current, comprising connecting the armature in series with the field for normal operation with a condenser and a rectifier connected across the source of alternating current, thereafter disconnecting the field from the series relation with the rotating armature and connecting the field in parallel with the armature and in series with the rectifier to act as an electrical load on the armature, while connecting the charged condenser across the field to discharge the condenser as a pulse through the field to create an initial excitation for the field to initiate dynamic braking of the rotating armature to bring it to a standstill.
Claim 7
Dependent Claim
26 words
The method defined in claim 4 further characterized by a bucking voltage relation between the charged condenser and the rotating armature before initiation of dynamic braking.
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |