Hybrid power relay with thermal protection
First Claim
1. A hybrid power relay for making and breaking an electrical circuit, comprising:
- electromagnetically operated contacts for making and breaking the circuit, a solid state switch connected across the contacts, means responsive to a control signal for actuating the solid state switch and the contacts such that the solid state switch closes before the contacts to make the circuit and the contacts open before the solid state switch to break the circuit, and means for monitoring the temperature of the solid state switch and opening the switch in the event of a rise in temperature produced by abnormal current flow in the switch due to failure of the contacts to make and maintain the circuit.
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Accused Products
Abstract
Hybrid power relay for making and breaking an electrical circuit which includes electromagnetically operated contacts for making and breaking the circuit, a solid state switch connected across the contacts, a control circuit responsive to a control signal for actuating the solid state switch and the contacts such that the solid state switch closes before the contacts to make the circuit and the contacts open before the solid state switch to break the circuit, and a protective circuit for monitoring the temperature of the solid state switch and opening the switch in the event of a rise in temperature produced by abnormal current flow in the switch due to failure of the contacts to make and maintain the circuit.
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Citations
20 Claims
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1. A hybrid power relay for making and breaking an electrical circuit, comprising:
- electromagnetically operated contacts for making and breaking the circuit, a solid state switch connected across the contacts, means responsive to a control signal for actuating the solid state switch and the contacts such that the solid state switch closes before the contacts to make the circuit and the contacts open before the solid state switch to break the circuit, and means for monitoring the temperature of the solid state switch and opening the switch in the event of a rise in temperature produced by abnormal current flow in the switch due to failure of the contacts to make and maintain the circuit.
- View Dependent Claims (2, 3, 4, 5, 6)
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7. A hybrid power relay for making and breaking a three-phase electrical circuit, comprising:
- electromagnetically operated contacts for making and breaking each of the three-phases of the circuit, solid state switch connected across the contacts, means responsive to a control signal for actuating the solid state switches and the contacts such that the solid state switches close before the contacts to make the circuits and the contacts open before the solid state switches to break the circuits, and means for monitoring the temperature of the solid state switches and opening the switches in the event of a rise in temperature produced by abnormal current flow in the switches due to failure of the contacts to make and maintain the circuits.
- View Dependent Claims (8, 9, 10, 11, 12)
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13. A hybrid power relay for making and breaking an electrical circuit, comprising:
- electromagnetically operated contacts for making and breaking the circuit, first and second silicon controlled rectifiers (SCRs) connected back-to-back across the contacts, with the cathode of the first SCR and the anode of the second SCR connected to one of the contacts and the anode of the first SCR and the cathode of the second SCR connected to the other contact, a DC power supply, means including optocouplers connected to the power supply and to the control gates of the SCR(s for biasing the SCRs to an ON state when the power supply is energized, an operating coil for closing the contacts when energized, and a switching circuit responsive to the control signal for simultaneously applying operating power to the DC power supply and to the operating coil, with the SCRs turning on before the contacts close to make the circuit and the contacts opening before the SCRs turn off to break the circuit.
- View Dependent Claims (14, 15, 16, 17)
- 18. A hybrid power relay comprising an electromechanical relay having contacts for making and breaking an electrical circuit and a coil for operating the contacts inside a housing with terminals outside the housing for connecting the contacts to line and load conductors and for connecting the operating coil to an AC power source, and a solid state switching module having a solid state switching device in a housing mounted to the contactor housing, with leads extending from the switching module to the line and load terminals to connect the solid state switching device electrically in parallel with the electromechanical relay contacts.
Specification