US4862052A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for stopping an electric motor
Assignee: Allen Bradley Co LLC
•
Filing: 1988-03-08
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Granted: 1989-08-29
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Expires: 2008-03-08
Abstract
Abstract An electric motor is braked by sensing the polarity of voltage of the alternating electricity for powering the motor and sensing the polarity of the voltage induced in the motor by the back electromotive force. When these polarities are opposite the electricity is applied to the motor to generate a braking torque. The application of the electricity is stopped a given interval after it begins to be applied during consecutive voltage cycles. This interval is derived from the time period between when braking commenced to when the electricity was applied during consecutive cycle.
Inventors
- 👤 Peter J. Unsworth
- 👤 John C. Merrison
- 👤 Timothy M. Rowan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:52
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/06; H02P3/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
109 words
A method for braking an electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity from the source to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source and the back emf voltage being of opposite polarities; stopping the application of the electricity to the motor a given interval after the electricity is applied to the motor during consecutive cycles of the source voltage.
Claim 2
Independent Claim
109 words
A method for braking an electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity from the source to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source and the back emf voltage being of opposite polarities; stopping the application of the electricity to the motor a given interval after the electricity is applied to the motor during consecutive cycles of the source voltage.
Claim 3
Dependent Claim
43 words
The method as in claim 1 further comprising: measuring the time interval between when the brake signal occurs and when the electricity is applied to the motor during consecutive cycles of the alternating voltage; and deriving the given interval from the measured interval.
Claim 4
Dependent Claim
17 words
The method as recited in claim 1 wherein the given interval is a fixed amount of time.
Claim 5
Dependent Claim
45 words
The method as recited in claim 1 further comprising deriving the given interval from the period between a first point in time determined from when the brake signal commenced until a second point in time determined from when the electricity was applied during every cycle.
Claim 6
Independent Claim
112 words
A method for braking an electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source of alternating electricity and the back emf voltage being of opposite polarities; determining when the motor reaches a given speed; and stopping the application of electricity to the motor after a period of time from when the motor reached the given speed.
Claim 7
Independent Claim
112 words
A method for braking an electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source of alternating electricity and the back emf voltage being of opposite polarities; determining when the motor reaches a given speed; and stopping the application of electricity to the motor after a period of time from when the motor reached the given speed.
Claim 8
Dependent Claim
28 words
The method as recited in claim 5 wherein said given speed is in the range of 0 to 50 percent of the normal running speed of the motor.
Claim 9
Dependent Claim
39 words
The method as recited in claim 5 further comprising measuring the time interval from when the brake signal commenced until the motor reaches the given speed; and wherein the period of time is derived from the measured time interval.
Claim 10
Dependent Claim
20 words
The method as recited in claim 7 wherein the period of time is substantially equal to the measured time interval.
Claim 11
Dependent Claim
26 words
The method as recited in claim 5 further comprising determining when the motor reaches the given speed using the sensed polarity of the back emf voltage.
Claim 12
Independent Claim
142 words
A method for braking an alternating current electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source and the back emf voltage being of opposite polarities; detecting when the electricity applied to the motor during consecutive cycles of the electricity from the source after having been applied during other than consecutive cycles; calculating the elapsed time from when electricity is detected being applied to the motor during consecutive cycles; and stopping the step of applying electricity to the motor after a given amount of time has elapsed.
Claim 13
Independent Claim
142 words
A method for braking an alternating current electric motor in response to a brake signal comprising the steps of: sensing the polarity of the voltage from a source of alternating electricity; sensing the polarity of the back emf voltage from the motor; applying electricity to the motor in a manner which tends to slow the rotation of the motor, the application of electricity being in response to the voltage from the source and the back emf voltage being of opposite polarities; detecting when the electricity applied to the motor during consecutive cycles of the electricity from the source after having been applied during other than consecutive cycles; calculating the elapsed time from when electricity is detected being applied to the motor during consecutive cycles; and stopping the step of applying electricity to the motor after a given amount of time has elapsed.
Claim 14
Dependent Claim
34 words
The method as recited in claim 10 wherein said given interval is derived form the period of time between when the brake signal commenced to substantially when the electricity was applied during consecutive cycles.
Claim 15
Dependent Claim
45 words
The method as recited in claim 10 wherein said given interval is derived from the period between a first point in time determined from when the brake signal commenced until a second point in time determined from when the electricity was applied during consecutive cycles.
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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) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |