US3590352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field weakening circuit for a series field motor
Assignee: Schneider Electric USA Inc
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Filing: 1969-04-28
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Granted: 1971-06-29
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Expires: 1989-04-28
Abstract
Abstract A speed control circuit for a series field direct current motor. The circuit includes a reed relay that has a movable contact responsive to the current flow through the field and a resistance in a shunt circuit with the field. The reed relay through a transistor and a contactor causes the shunt circuit to be interrupted when the current flow through the motor increases above the predetermined value. The reed relay has a pair of coil windings arranged so that one of the windings generates a magnetic flux that opposes the flux generated by the current flow through the field and the other provides an output flux which adds to the flux generated by the field current so that movable contact will operate with a snap action. The flux outputs of each of the pair of coils is individually adjustable so the response of the relay to the upper and lower limits of a range of field current flow may be individually adjusted. The circuit further includes a capacitor which will cause the flux output of one of the coils to momentarily increase when the reed relay initially responds to an excess current in the field circuit.
Inventors
- 👤 Robert G Ries
- 👤 Kenneth W Retzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:37
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/298
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
272 words
A control circuit for a series field type direct current motor comprising: a solid-state control connected between a direct current source and the motor for supplying the motor with regulated pulses of direct current, an electromechanical switching device having a first pair of normally open contacts, a second pair of normally open contacts and a coil arranged to close the first and the second pairs of contacts when the coil is energized, a circuit controlling the energization of the coil from the source, a shunt for the series field of the motor, a first circuit including the first pair of contacts and a current coil connected in series between the field and the direct current source and in parallel with the solid-state control for connecting the motor directly across the source independently of the solid-state control, a reed relay physically positioned to be magnetically coupled to the current coil, said relay having a movable contact that is resiliently biased to a first position and arranged to be moved from the first position to a second position by the magnetic flux generated by the current flow through the current coil when the current flow through the first circuit exceeds a predetermined value, and means connected to be operative upon the closure of the second pair of contacts and including a contactor having a speed of response slower than the speed of response of the reed relay and controlled by the movable contact of the reed relay for connecting the shunt when the movable contact is in the first position and for disconnecting the shunt when the movable contact is in the second position.
Claim 2
Dependent Claim
272 words
A control circuit for a series field type direct current motor comprising: a solid-state control connected between a direct current source and the motor for supplying the motor with regulated pulses of direct current, an electromechanical switching device having a first pair of normally open contacts, a second pair of normally open contacts and a coil arranged to close the first and the second pairs of contacts when the coil is energized, a circuit controlling the energization of the coil from the source, a shunt for the series field of the motor, a first circuit including the first pair of contacts and a current coil connected in series between the field and the direct current source and in parallel with the solid-state control for connecting the motor directly across the source independently of the solid-state control, a reed relay physically positioned to be magnetically coupled to the current coil, said relay having a movable contact that is resiliently biased to a first position and arranged to be moved from the first position to a second position by the magnetic flux generated by the current flow through the current coil when the current flow through the first circuit exceeds a predetermined value, and means connected to be operative upon the closure of the second pair of contacts and including a contactor having a speed of response slower than the speed of response of the reed relay and controlled by the movable contact of the reed relay for connecting the shunt when the movable contact is in the first position and for disconnecting the shunt when the movable contact is in the second position.
Claim 3
Dependent Claim
161 words
The circuit as recited in claim 1 wherein the reed relay includes a pair of stationary contacts that are arranged so a first one of the pair of stationary contacts is engaged by the movable contact when the movable contact is at the first position and a second one of a pair of stationary contacts is engaged by the movable contact when the movable contact is at the second position, a first coil winding connected through a second circuit that includes the first stationary contact and the movable contact to the source when the movable contact is at the first position to produce a magnetic flux which opposes the flux generated by the current coil and a second coil winding connected through a third circuit that includes the second stationary contact and the movable contact to the source when the movable contact is at the second position to produce a magnetic flux which aids the flux generated by the current coil.
Claim 4
Dependent Claim
28 words
The circuit as recited in claim 2 wherein the second and third circuits each have means for adjusting the flux produced by the first and second coil windings.
Claim 5
Dependent Claim
123 words
The circuit as recited in claim 2 wherein the means controlled by the movable contact for disconnecting the shunt includes a transistor, a circuit including a base of the transistor and the first stationary contact for connecting the base to the source when the movable contact is at the first position and the contactor has a coil winding connected to the source through a circuit that includes an emitter and a collector of the transistor so as to be energized when the movable contact is in the first position and a pair of contacts in the shunt for disconnecting the shunt when the movable contact is at the second position and connecting the shunt when the movable contact is at the first position.
Claim 6
Dependent Claim
59 words
The circuit as recited in claim 2 wherein the third circuit includes a capacitance connected in the third circuit in series with the second coil to be charged from the source when the movable contact engages the second contact so that the flux generated by the second coil is increased when the movable contact initially engages the second contact.
Claim 7
Dependent Claim
123 words
The circuit as recited in claim 3 wherein the means controlled by the movable contact for disconnecting the shunt includes a transistor, a circuit including a base of the transistor and the first stationary contact for connecting the base to the source when the movable contact is at the first position and the contactor has a coil winging connected to the source through a circuit that includes an emitter and a collector of the transistor so as to be energized when the movable contact is in the first position and a pair of contacts in the shunt for disconnecting the shunt when the movable contact is at the second position and connecting the shunt when the movable contact is at the first position.
Claim 8
Dependent Claim
59 words
The circuit as recited in claim 6 wherein the third circuit includes a capacitance connected in the third circuit in series with the second coil to be charged from the source when the movable contact engages the second contact so that the flux generated by the second coil is increased when the movable contact initially engages the second contact.
Claim 9
Dependent Claim
59 words
The circuit as recited in claim 3 wherein the third circuit includes a capacitance connected in the third circuit in series with the second coil to be charged from the source when the movable contact engages the second contact so that the flux generated by the second coil is increased when the movable contact initially engages the second contact.
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) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |