Fail-safe time delay circuit

Details Fail-safe time delay circuit Fail-safe time delay circuit

1978-01-31

1979-06-05

Goldberg, Gerald

Electricity: electrical systems and devices

Control circuits for electromagnetic devices

For relays or solenoids

361187, 361191, 361195, H01H 4718

Patent

active

041575806

ABSTRACT:
A fail-safe time delay circuit is provided to produce an output a predetermined time, and no less than a predetermined time after an input stimulus. The circuit includes a driving circuit for a pair of relays which are operated at slightly greater than 50% duty cycle and out of phase such that, except when the circuit is de-energized, at least one of the relays is always energized. The contacts of the two relays are employed in a balanced voltage amplifier to produce a bi-polar signal, with the magnitude of both polarities increasing, with the time required for the increase to a defined threshold establishing the time delay. A pair of threshold circuits are coupled to the output of the balanced voltage amplifier such that each threshold circuit (one responding to the positive portion, and the other the negative portion of the bi-polar output) is energized when the respective portion of the bi-polar signal is detected to reach the associated threshold. Each of the threshold circuits provides an input to a vital AND gate such that only when the excursion in the bi-polar signal exceeds the threshold of both threshold circuits will the vital AND gate produce an output to energize a load.

REFERENCES:
patent: 3579703 (1971-05-01), Schmermund
patent: 3636411 (1972-01-01), Bulloch
patent: 3832599 (1974-08-01), Grundy
patent: 4044272 (1977-08-01), Darrow
patent: 4059845 (1977-11-01), Kolkman

Affiliated with

Also associated with

Rating

Fail-safe time delay circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fail-safe time delay circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fail-safe time delay circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1710308