US3628112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dynamic braking of electric motors with load changing during braking
Assignee: Individual
•
Filing: 1970-06-01
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Granted: 1971-12-14
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Expires: 1990-06-01
Abstract
Abstract A motor system for energizing and deenergizing an electric motor and for dynamically braking the motor to a halt after deenergization. When the motor is turned off, a dynamic braking circuit is connected in series with the motor windings to assure generator action and to provide for dissipation of the kinetic energy of the motor in the form of heat. A current-limiting resistor in the braking circuit absorbs much of the energy immediately upon the initiation of braking. An electronic control circuit responds to the integral of the energy absorbed in the braking circuit. When the absorbed energy has reached a predetermined proportion of the total kinetic energy of the motor to be dissipated, the control circuit causes the current-limiting resistor to be short-circuited, thereby to permit larger currents to flow in the braking circuit, bringing the motor quickly to a halt.
Inventors
- 👤 Thomas A O Gross
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:33
CPC Classifications
H; H02; H02P; H02P3/00; H02P3/06; H02P3/18; H02P3/22
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
119 words
A dynamically braked motor system comprising: an electric motor operable both in a motor mode and in a generator mode; supply terminals connectable to a source of electrical power; switching means for controlling the connection of said motor to said supply terminals; means made operative upon disconnection of said motor from said supply terminals for completing a dynamic-braking circuit with said motor through a current-limiting impedance; energy-responsive means for generating a time-varying signal representing the cumulative amount of energy dissipated in said dynamic-braking circuIt; and means responsive to the attainment by said signal of a predetermined value for automatically reducing the value of the impedance in said dynamic-braking circuit after a predetermined quantity of energy has been dissipated therein.
Claim 2
Dependent Claim
119 words
A dynamically braked motor system comprising: an electric motor operable both in a motor mode and in a generator mode; supply terminals connectable to a source of electrical power; switching means for controlling the connection of said motor to said supply terminals; means made operative upon disconnection of said motor from said supply terminals for completing a dynamic-braking circuit with said motor through a current-limiting impedance; energy-responsive means for generating a time-varying signal representing the cumulative amount of energy dissipated in said dynamic-braking circuIt; and means responsive to the attainment by said signal of a predetermined value for automatically reducing the value of the impedance in said dynamic-braking circuit after a predetermined quantity of energy has been dissipated therein.
Claim 3
Dependent Claim
125 words
A control system for energizing and for dynamically braking an electric motor operable both in a motor mode and in a generator mode comprising: supply terminals connectable to a source of electrical power; switching means for controlling the connection of such a motor to said supply terminals; means made operative upon disconnection of such motor from said supply terminals, for completing a dynamic-braking circuit with such motor through a current-limiting impedance; energy-responsive means for generating a time-varying signal representing the cumulative amount of energy dissipated in said dynamic-braking circuit; and means responsive to the attainment by said signal of a predetermined value for automatically reducing the value of the impedance in said dynamic braking circuit after a predetermined quantity of energy has been dissipated therein.
Claim 4
Dependent Claim
125 words
A control system for energizing and for dynamically braking an electric motor operable both in a motor mode and in a generator mode comprising: supply terminals connectable to a source of electrical power; switching means for controlling the connection of such a motor to said supply terminals; means made operative upon disconnection of such motor from said supply terminals, for completing a dynamic-braking circuit with such motor through a current-limiting impedance; energy-responsive means for generating a time-varying signal representing the cumulative amount of energy dissipated in said dynamic-braking circuit; and means responsive to the attainment by said signal of a predetermined value for automatically reducing the value of the impedance in said dynamic braking circuit after a predetermined quantity of energy has been dissipated therein.
Claim 5
Dependent Claim
107 words
A control system for energizing and for dynamically braking an electric motor which is capable of generating electrical currents, said system comprising: supply terminals connectable to a source of current; switching means for controlling the connection of such a motor to said supply terminals; current-limiting impedance means; means made operative upon disconnection of such motor from said supply terminals for completing a dynamic-braking circuit through such motor and said impedance means; and load-reducing means responsive to the dissipation of a predetermined quantity of energy by said braking circuit for reducing the value of the impedance means in said braking circuit, thereby to reduce the total braking interval.
Claim 6
Dependent Claim
107 words
A control system for energizing and for dynamically braking an electric motor which is capable of generating electrical currents, said system comprising: supply terminals connectable to a source of current; switching means for controlling the connection of such a motor to said supply terminals; current-limiting impedance means; means made operative upon disconnection of such motor from said supply terminals for completing a dynamic-braking circuit through such motor and said impedance means; and load-reducing means responsive to the dissipation of a predetermined quantity of energy by said braking circuit for reducing the value of the impedance means in said braking circuit, thereby to reduce the total braking interval.
Claim 7
Dependent Claim
25 words
The control system of claim 3 wherein said load reducing means is responsive to the time integral of dynamic-braking currents in said current-limiting impedance means.
Claim 8
Dependent Claim
14 words
The control system of claim 3 wherein said current-limiting impedance means is primarily resistive.
Claim 9
Dependent Claim
63 words
The control system of claim 5 wherein said load reducing means comprises: an integrating circuit connected across said current-limiting impedance means to derive an electrical signal representing the time integral of braking currents in said braking circuit; and second switching means responsive to the attainment by said electrical signal of a predetermined value for completing a shunt circuit around said current-limiting impedance means.
Claim 10
Dependent Claim
35 words
The control system of claim 6 wherein said second switching means comprises at least one solid state switching device switchable between a high-resistance condition and a low-resistance shunt condition in response to said electrical signal.
Claim 11
Dependent Claim
15 words
The control system of claim 7 wherein said solid-state-switching device is a silicon controlled rectifier.
Claim 12
Dependent Claim
69 words
The control system of claim 3 further comprising a universal motor having stator and rotor windings, and wherein said switching means is operable in an energizing mode to connect the windings of said universal motor in series with each other and with said supply terminals, and in a deenergizing mode to disconnect said windings from said supply terminals and connect them in inverted series relationship with said braking circuit.
Claim 13
Dependent Claim
110 words
The control system of claim 9 wherein said braking circuit includes electrical energy storage means, unilaterally conductive means for delivering electrical energy to said storage means from said supply terminals when said switching means is in its energizing mode, means for discharging said storage means into the windings of such motor when said switching means is switched to its deenergizing mode thereby to assure generative coupling between the windings of such motor, and unilaterally conductive shunt circuit means connected in parallel to said energy storage means to permit currents generated iN the windings of such motor to continue to flow after the energy stored in said storage means is exhausted.
Claim 14
Dependent Claim
78 words
The control system of claim 3 further comprising a direct current motor, a reversing switch to control the direction of rotation of said motor, and wherein said switching means is operable in an energizing mode to connect the windings of said motor to a source of direct current potential through said reversing switch and in a deenergizing mode to disconnect said windings from said source and connect them in series with said braking circuit through said reversing switch.
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 |