US3555356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor protector
Assignee: Robertshaw Controls Co
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Filing: 1969-04-01
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Granted: 1971-01-12
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Expires: 1989-04-01
Abstract
Abstract A motor protector circuit using thermal responsive sensors for controlling the circuit operation to protect the motor windings from damage due to overheating and using a current responsive electromagnetic sensing device for controlling the circuit operation to protect the motor windings from damage due to the prolonged application of current well in excess of the normal starting current for the motor. The thermal responsive sensors and the current responsive device are connected to control the operation of a thyristor which in turn controls the contactor connected to control the flow of current to the motor.
Inventors
- 👤 Franz S Kaiser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:53
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/085; H02H5/00; H02H5/04; H02H5/041
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
165 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electrIc motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a condition altering the operation of the relay to terminate energization of the motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the winding of the electric motor, said device when responding to said predetermined level of current flow altering said circuit causing said electronic switch means to be placed in a condition altering the operation of said relay to terminate energization of the motor windings.
Claim 2
Dependent Claim
165 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electrIc motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a condition altering the operation of the relay to terminate energization of the motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the winding of the electric motor, said device when responding to said predetermined level of current flow altering said circuit causing said electronic switch means to be placed in a condition altering the operation of said relay to terminate energization of the motor windings.
Claim 3
Dependent Claim
40 words
The combination in accordance with claim 1 wherein said device includes a set of electrical contacts connected in said circuit and operated to effect said altering of said circuit when said device responds to said predetermined level of current flow.
Claim 4
Dependent Claim
212 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a condition altering the operation of the relay to terminate energization of the motor windings when the temperature of the responsive sensor rises to a predetermined temperature with the altered operation of the relay effecting operation of a set of electrical contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in said condition until the temperature of the temperature responsive sensor drops to a lower predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the windings of the electric motor, said device when responding to said predetermined level of current flow changing said circuit causing said electronic switch means to be placed in a condition altering the operation of said relay to terminate energization of the motor windings.
Claim 5
Dependent Claim
212 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a condition altering the operation of the relay to terminate energization of the motor windings when the temperature of the responsive sensor rises to a predetermined temperature with the altered operation of the relay effecting operation of a set of electrical contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in said condition until the temperature of the temperature responsive sensor drops to a lower predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the windings of the electric motor, said device when responding to said predetermined level of current flow changing said circuit causing said electronic switch means to be placed in a condition altering the operation of said relay to terminate energization of the motor windings.
Claim 6
Dependent Claim
51 words
The combination in accordance with claim 3 wherein said device includes a set of electrical contacts connected in said circuit and operated for so long as said device is responding to said predetermined level of current flow, said set of electrical contacts when so operated effecting said changing of said circuit.
Claim 7
Dependent Claim
35 words
The combination in accordance with claim 3 wherein said circuit includes a resistive element with said set of contacts connected to said resistive element to short out said resistive element when said contacts are closed.
Claim 8
Dependent Claim
217 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the relay being energized when the electronic switch means is in a conducting mode, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a nonconducting mode deenergizing the relay to terminate energization of motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature, the deenergized relay effecting operation of a set of contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in the nonconducting mode until the temperAture of the temperature responsive sensor drops to a predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the windings of the electric motor, said device when responding to said predetermined level of current flow changing said circuit causing said electronic switch means to be placed in a nonconducting mode deenergizing said relay to terminate energization of the motor windings.
Claim 9
Dependent Claim
217 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means controlled by a circuit connected to the electronic switch means, the relay being energized when the electronic switch means is in a conducting mode, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a nonconducting mode deenergizing the relay to terminate energization of motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature, the deenergized relay effecting operation of a set of contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in the nonconducting mode until the temperAture of the temperature responsive sensor drops to a predetermined temperature the combination with said circuit connected to said electronic switch means of a device responsive to a predetermined level of current flow to the windings of the electric motor, said device when responding to said predetermined level of current flow changing said circuit causing said electronic switch means to be placed in a nonconducting mode deenergizing said relay to terminate energization of the motor windings.
Claim 10
Dependent Claim
40 words
The combination in accordance with claim 6 wherein said device includes a set of electrical contacts connected in said circuit and operated to effect said changing of said circuit when said device responds to said predetermined level of current flow.
Claim 11
Dependent Claim
229 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means connected to a source of power and controlled by a circuit connected to the electronic switch means, the relay being energized when the electronic switch means in a conducting mode, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a nonconducting mode deenergizing the relay to terminate energization of the motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature, the deenergized relay effecting operation of a set of contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in the nonconducting mode until the temperature of the temperature responsive sensor drops to a predetermined temperature the combination with said electronic switch means of a device responsive to a predetermined level of current flow to the winding of the electric motor, said device when responding to said predetermined level of current flow interrupting the connection of said power source to said electronic switch means causing said electronic switch means to be placed in a nonconducting mode deenergizing said relay to terminate energization of the motor windings.
Claim 12
Dependent Claim
229 words
In control circuitry responsive to temperature of the type wherein the energization of the windings of an electric motor is controlled via a relay operated in accordance with the operation of an electronic switch means connected to a source of power and controlled by a circuit connected to the electronic switch means, the relay being energized when the electronic switch means in a conducting mode, the circuit including at least one temperature responsive sensor positioned in the windings of the electric motor, the circuit placing the electronic switch means in a nonconducting mode deenergizing the relay to terminate energization of the motor windings when the temperature of the temperature responsive sensor rises to a predetermined temperature, the deenergized relay effecting operation of a set of contacts connected in the circuit causing said circuit to be altered so the electric switch means remains in the nonconducting mode until the temperature of the temperature responsive sensor drops to a predetermined temperature the combination with said electronic switch means of a device responsive to a predetermined level of current flow to the winding of the electric motor, said device when responding to said predetermined level of current flow interrupting the connection of said power source to said electronic switch means causing said electronic switch means to be placed in a nonconducting mode deenergizing said relay to terminate energization of the motor windings.
Claim 13
Dependent Claim
67 words
The combination in accordance with claim 8 wherein said device includes a set of electrical contacts connected to control the connection of said power source to said power electronic switch means and operated for so long as said device is responding to said predetermined level of current flow, said set electrical contacts when so operated interrupting the connection of said power source to said electronic switch means.
References Cited (Backward Citations)
US3329869A
Cited
US3366843A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |