US3628110A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Braking circuit for brushless dc motor
Assignee: Unisys Corp
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Filing: 1969-09-26
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Granted: 1971-12-14
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Expires: 1989-09-26
Abstract
Abstract A brushless DC motor (BDCM) of the type employing a permanent magnet rotor and a wound stator and in which each side of the power supply is connected to selected portions of the stator winding through a different group of commutating switches. Braking is accomplished by applying a braking signal which serves to close all of the switches in one group and open all of the switches in the other group of the commutating switches.
Inventors
- 👤 William M Casaday
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:12
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/24
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
A braking circuit for a BDCM of the type including a stator winding, a permanent magnet rotor, rotor position sensing means, and first and second groups of commutating switches responsive to the output of said sensing means for sequentially connecting sections of said stator winding to first and second power busses, respectively, said braking circuit comprising means to receive a braking signal, means for simultaneously opening all switches in said first group while simultaneously closing all switches in said second group in response to a braking signal.
Claim 2
Dependent Claim
87 words
A braking circuit for a BDCM of the type including a stator winding, a permanent magnet rotor, rotor position sensing means, and first and second groups of commutating switches responsive to the output of said sensing means for sequentially connecting sections of said stator winding to first and second power busses, respectively, said braking circuit comprising means to receive a braking signal, means for simultaneously opening all switches in said first group while simultaneously closing all switches in said second group in response to a braking signal.
Claim 3
Dependent Claim
76 words
The apparatus of claim 1 wherein each of the commutating switches in said groups includes a transistor-switching circuit responsive to an individual position sensor, and wherein said switching circuit further includes an output transistor connected serially between said stator winding and one of said power busses, each of said output transiStors being normally biased to cut off and further connected so as to be turned on in response to a signal from the associated position sensor.
Claim 4
Dependent Claim
46 words
The apparatus of claim 2 further including means to disable each of said position sensors in response to a braking signal and auxiliary means to turn on the output transistors in said second group of switches regardless of the operating condition of the associated position sensors.
Claim 5
Dependent Claim
53 words
The apparatus of claim 3 in which each position sensor is a photosensor coupled to provide a sensor output signal to the corresponding transistor-switching circuit when the photosensor is illuminated, said braking circuit further including means to divert a sensor output signal from the corresponding transistor-switching circuit in response to a braking signal.
Claim 6
Dependent Claim
33 words
The apparatus of claim 3 in which said auxiliary means includes means to saturate each of the output transistors in the transistor-switching circuit of said second group in response to a braking 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) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |