Patent EP0073392A1 successfully refreshed from Google Patents.
US3602771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state de-energizer having current sensing loops
Assignee: Siemens Energy and Automation Inc
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Filing: 1969-10-13
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Granted: 1971-08-31
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Expires: 1989-10-13
Abstract
Abstract Overload and other excessive current conditions as regards an electric motor are sensed by current sensing loops which form the primary winding of respective transformers. The voltage developed across the secondary windings are rectified and supplied to a deenergizing circuit which additionally includes a holding circuit and a timing circuit. In the event of an overload condition, the current supply to the electric motor is interrupted and also a time delay is effected before reset occurs assuming that electric power is again available.
Inventors
- 👤 Dennis C Winfield Walstad
- 👤 Dale F Aurora Willcox
- 👤 Walter Robert Knopf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:08
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/02; H02H3/06; H02H3/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
372 words
In a control device for controlling the operation of an electric motor or the like, the combination with a source of electric current, of conductors connecting the current supply source with the motor, a contactor for controlling flow of said current to the motor, said contactor having a coil in series connected relation with the control device and which when energized causes the contactor to close, said device including current sensing loops formed of metal and which comprise the core of respective transformers, each current sensing loop having one of said conductors passing through the loop and which forms the primary winding of the respective transformers, each of said transformers having a secondary winding in inductive relation with its loop, a current sensing circuit in electrical connection with the secondary windings for sensing the magnitude and duration of excessive peak currents flowing in the conductors which pass through the said loops, a timing circuit consisting of a resistor and a first condenser, said resistor having a relatively high ohmic value and having a series connected relation with the first condenser, a parallel conducting circuit consisting of a magnetically actuated reed switch and an inductance coil, said reed switch and coil having a series connected relation and said coil having an inductive relation with the reed switch, whereby the reed switch closes when current is caused to flow through the inductance coil, said inductance coil and the reed switch when closed providing a current path of less impedance than the resistor-first condenser series circuit, a trigger diode which is sensitive to voltage in electrical connection with the secondary windings and forming an element of the sensing circuit, a second condenser in electrical connection with the trigger diode and being located between the same and the secondary windings, whereby when the second condenser is charged to a preselected voltage the diode closes to discharge the same and cause current to flow through the diode, and means including a transistor so connected to the diode that its base is energized upon current flowing through the diode, and said transistor having electrical connection in shunt relation across the inductance coil, whereby current flow through the coil is terminated when the base of the transistor is energized.
Claim 2
Dependent Claim
372 words
In a control device for controlling the operation of an electric motor or the like, the combination with a source of electric current, of conductors connecting the current supply source with the motor, a contactor for controlling flow of said current to the motor, said contactor having a coil in series connected relation with the control device and which when energized causes the contactor to close, said device including current sensing loops formed of metal and which comprise the core of respective transformers, each current sensing loop having one of said conductors passing through the loop and which forms the primary winding of the respective transformers, each of said transformers having a secondary winding in inductive relation with its loop, a current sensing circuit in electrical connection with the secondary windings for sensing the magnitude and duration of excessive peak currents flowing in the conductors which pass through the said loops, a timing circuit consisting of a resistor and a first condenser, said resistor having a relatively high ohmic value and having a series connected relation with the first condenser, a parallel conducting circuit consisting of a magnetically actuated reed switch and an inductance coil, said reed switch and coil having a series connected relation and said coil having an inductive relation with the reed switch, whereby the reed switch closes when current is caused to flow through the inductance coil, said inductance coil and the reed switch when closed providing a current path of less impedance than the resistor-first condenser series circuit, a trigger diode which is sensitive to voltage in electrical connection with the secondary windings and forming an element of the sensing circuit, a second condenser in electrical connection with the trigger diode and being located between the same and the secondary windings, whereby when the second condenser is charged to a preselected voltage the diode closes to discharge the same and cause current to flow through the diode, and means including a transistor so connected to the diode that its base is energized upon current flowing through the diode, and said transistor having electrical connection in shunt relation across the inductance coil, whereby current flow through the coil is terminated when the base of the transistor is energized.
Claim 3
Dependent Claim
89 words
A control device for controlling the operation of an electric motor or the like as defined by claim 1, wherein the transistor is of the NPN-type, and wherein the second condenser discharges through the trigger diode to energize the base of the transistor when a current of overload magnitude and existing for a predetermined period of time is sensed by the current sensing circuit, whereby current flow through the inductance coil is terminated and the reed switch opens to deenergize the Contactor coil and stop operation of the motor.
Claim 4
Dependent Claim
290 words
In a control device for controlling the operation of an electric motor or the like, the combination with a current supply source, of conductors connecting the current supply source with the motor, a contactor for controlling flow of said current to the motor, said contactor having a coil which when energized causes the contactor to close, said coil having a series connected relation with said control device and the said series connected arrangement being connected across the current supply source in shunt relation with the motor but in advance of the contactor, said device including current sensing loops formed of metal and which comprise the core of respective transformers, each current sensing loop having one of said conductors which connect the contactor with the motor passing through the loop and which form the primary winding of the respective transformers, each of said transformers having a secondary winding in inductive relation with its loop, a current sensing circuit in connected relation with the secondary windings of the transformers, rectifying means in the circuit of each secondary winding, whereby the sensing circuit is supplied with pulsating direct current, said sensing circuit including a first condenser connected across the terminals of the sensing circuit, a transistor, a trigger diode connected between the first condenser and the base of the transistor, whereby when the first condenser is charged to a preselected voltage the trigger diode is caused to close and the first condenser is discharged through the same to saturate the base of the transistor, and a holding circuit in electrical connection with the transistor, said holding circuit operating to interrupt the shunt connection when the base of the transistor is saturated to thereby deenergize the contactor coil and terminate current to the motor.
Claim 5
Dependent Claim
290 words
In a control device for controlling the operation of an electric motor or the like, the combination with a current supply source, of conductors connecting the current supply source with the motor, a contactor for controlling flow of said current to the motor, said contactor having a coil which when energized causes the contactor to close, said coil having a series connected relation with said control device and the said series connected arrangement being connected across the current supply source in shunt relation with the motor but in advance of the contactor, said device including current sensing loops formed of metal and which comprise the core of respective transformers, each current sensing loop having one of said conductors which connect the contactor with the motor passing through the loop and which form the primary winding of the respective transformers, each of said transformers having a secondary winding in inductive relation with its loop, a current sensing circuit in connected relation with the secondary windings of the transformers, rectifying means in the circuit of each secondary winding, whereby the sensing circuit is supplied with pulsating direct current, said sensing circuit including a first condenser connected across the terminals of the sensing circuit, a transistor, a trigger diode connected between the first condenser and the base of the transistor, whereby when the first condenser is charged to a preselected voltage the trigger diode is caused to close and the first condenser is discharged through the same to saturate the base of the transistor, and a holding circuit in electrical connection with the transistor, said holding circuit operating to interrupt the shunt connection when the base of the transistor is saturated to thereby deenergize the contactor coil and terminate current to the motor.
Claim 6
Dependent Claim
67 words
A control device for controlling the operation of an electric motor or the like as defined by claim 3, wherein the sensing circuit includes a first resistor in series with the trigger diode and located in advance of the first condenser between the same and the secondary windings, said first resistor having a value in ohms selected for predetermining the charging rate of the said first condenser.
Claim 7
Dependent Claim
112 words
A control device for controlling the operation of an electric motor or the like as defined by claim 3, wherein the sensing circuit includes a first resistor in series with the trigger diode and located in advance of the first condenser between the same and the secondary windings, said first resistor having a value in ohms selected for predetermining the charging rate of the first condenser, and 9 second resistor connected in parallel relation with the first condenser and between the first resistor and the secondary windings, said second resistor providing a discharge path for the first condenser so that the same may discharge to a full extent on each discharging operation.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |