US4761592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric motor with overload protection circuit
Assignee: Grundfos AS
•
Filing: 1987-03-12
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Granted: 1988-08-02
•
Expires: 2007-03-12
Abstract
Abstract An electric motor comprising a motor overload protection such as a thermal switch and a main relay for controlling a multipolar switch in the voltage supply conductors of the motor. The thermal switch and the main relay are mounted in a control circuit in parallel with the voltage supply conductors. An auxiliary relay is coupled in parallel with the main relay and can connect an auxiliary motor via a contact arm when the thermal switch is switched off.
Inventors
- 👤 Bjarne Dissing
- 👤 Niels D. Jensen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:26
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
An electric motor comprising a motor overload protection circuit and a main relay for controlling a multipolar switch in the voltage supply conductors of the motor, said main relay breaking the connection with the voltage supply conductors when the protection circuit is activated, and further comprising an auxiliary relay for controlling an auxiliary motor when the protection circuit is activated, said main relay and said auxiliary relay being mounted in a terminal box for the electric motor and said auxiliary relay being connected in parallel with the main relay.
Claim 2
Dependent Claim
89 words
An electric motor comprising a motor overload protection circuit and a main relay for controlling a multipolar switch in the voltage supply conductors of the motor, said main relay breaking the connection with the voltage supply conductors when the protection circuit is activated, and further comprising an auxiliary relay for controlling an auxiliary motor when the protection circuit is activated, said main relay and said auxiliary relay being mounted in a terminal box for the electric motor and said auxiliary relay being connected in parallel with the main relay.
Claim 3
Dependent Claim
21 words
An electric motor as claimed in claim 1, wherein the parallel connected relays are connected in series with the protection circuit.
Claim 4
Dependent Claim
32 words
An electric motor as claimed in claim 2, wherein the series connection of the relays and the protection circuit is connected to one phase of the voltage supply conductors and ground, respectively.
Claim 5
Dependent Claim
19 words
An electric motor as claimed in claim 2 wherein an external control means is insertable in said series connection.
Claim 6
Dependent Claim
17 words
An electric motor as claimed in claim 4, wherein said external control means comprises a relay control.
Claim 7
Dependent Claim
31 words
An electric motor as claimed in claim 1, wherein the auxiliary motor comprises a corresponding main relay for controlling a multipolar switch in the voltage supply conductors of the auxiliary motor.
Claim 8
Dependent Claim
24 words
An electric motor as claimed in claim 6, further comprising a thermal switch connected in series with the main relay of the auxiliary motor.
Claim 9
Dependent Claim
36 words
An electric motor as claimed in claim 7, wherein the series connection of the relay and the thermal switch of the auxiliary motor are connected to one phase of the voltage supply conductors and ground, respectively.
Claim 10
Dependent Claim
19 words
An electric motor as claimed in claim 7, wherein an external control means is insertable in said series connection.
Claim 11
Dependent Claim
17 words
An electric motor as claimed in claim 9, wherein said external control means comprises a relay control.
Claim 12
Dependent Claim
17 words
An electric motor as claimed in claim 7, wherein the auxiliary motor comprises a speed control module.
Claim 13
Dependent Claim
16 words
An electric motor as claimed in claim 1, wherein said protection circuit comprises a thermal switch.
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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) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |