Zero-current a.c. switching system
AssigneeElectronic Instrument & Specialty Corp.
InventorBjorn E. Valeur
Life of this patent
Estimating the term…
Abstract
A zero-current a.c. switching system is provided for controlling actuation of relay contacts between a power supply and a load. A primary switch selectively energizes the relay to maintain the relay contacts in the closed state. The load current flowing through the relay contacts to the load is sensed. A secondary switch responds to the sensed load current for normally conducting to energize the relay in parallel with the primary switch. The secondary switch ceases conducting each time the load current drops below a predetermined level to cease energizing the relay and open the relay contacts the next time the load current drops below the predetermined level following the opening of the primary switch.
Claims31
A zero-current a.c. switching system for controlling actuation of relay contacts between a power supply and a load comprising:
- means for sensing the load current flowing through the relay contacts to the load;
- primary switching means for selectively energizing the relay to maintain the relay contacts in the closed state;
- and
- secondary switching means, responsive to said means for sensing, for normally conducting to energize the relay in parallel with said primary switching means, and for ceasing conducting each time the load current drops below a predetermined level to cease energizing the relay and open the relay contacts the next time the load current drops below said predetermined level following the opening of said primary switching means.
A zero-current a.c. switching system for controlling actuation of relay contacts between a power supply and a load comprising:
- diode means, responsive to a load current of at least a predetermined level, for providing a drive signal;
- LED means responsive to said drive signal for emitting radiation;
- primary switching means for selectively energizing the relay to maintain the relay contacts in the closed state;
- and
- secondary switching means, including semiconductor means responsive to said emission of radiation from said LED means, for maintaining a conducting condition to energize the relay in parallel with said primary switching means, and for ceasing conducting each time said LED means ceases emitting radiation to cease energizing the relay and open the relay contacts the next time the load current drops below said predetermined level following the opening of said primary switching means.
A zero-current a.c. switching system for controlling actuation of relay contacts between a power supply and a load comprising:
- means for inducing an output signal representative of the load current;
- means, responsive to said means for inducing, for providing an actuating signal in response to said load current dropping below a predetermined level;
- primary switching means for selectively energizing the relay to maintain the relay contacts in the closed state;
- and
- secondary switching means, responsive to said actuating signal, for maintaining a conducting condition to energize the relay in parallel with said primary switching means, and for ceasing conducting each time said actuating signal is ceased to de-energize the relay and open the relay contacts the next time the load current drops below said predetermined level following the opening of said primary switching means.
Dependencies are inferred from the claim text.