US3571707A — Voltage dropout sensor

Claim 1

Independent Claim 246 words

A voltage sensor for monitoring a multiphase alternating voltage having an undetermined amplitude level to indicate when the amplitude level of said voltage drops below a predetermined value comprising: A. means for rectifying said multiphase alternating voltage; B. a summing circuit means coupled to said means for rectifying said multiphase alternating voltage for totalizing the voltages of each phase producing a composite signal having a ripple voltage corresponding to the amplitude of said composite signal; C. a trigger circuit means having an input to which said composite signal is coupled, said trigger circuit means generating an alternating signal having a frequency corresponding to said ripple voltage of said composite signal when said composite signal exceeds a predetermined value; D. an electronic switching means coupled to said trigger circuit which conducts during one-half of each cycle of said alternating signal and is cut off during the other half of each cycle of said alternating signal; E. a capacitor coupled to said switching means for being charged when said electronic switching means is conducting and discharges when said switching means is not conducting; F. an electronic pulse forming circuit coupled to said capacitor for producing a pulse responsive to said capacitor charging to a predetermined level indicating that said amplitude of said multiphase alternating voltage has dropped below a predetermined level; and G. an indicator means coupled to said pulse forming means for being activated responsive to the amplitude of said multiphase voltage dropping below a predetermined level.

Claim 2

Dependent Claim 246 words

A voltage sensor for monitoring a multiphase alternating voltage having an undetermined amplitude level to indicate when the amplitude level of said voltage drops below a predetermined value comprising: A. means for rectifying said multiphase alternating voltage; B. a summing circuit means coupled to said means for rectifying said multiphase alternating voltage for totalizing the voltages of each phase producing a composite signal having a ripple voltage corresponding to the amplitude of said composite signal; C. a trigger circuit means having an input to which said composite signal is coupled, said trigger circuit means generating an alternating signal having a frequency corresponding to said ripple voltage of said composite signal when said composite signal exceeds a predetermined value; D. an electronic switching means coupled to said trigger circuit which conducts during one-half of each cycle of said alternating signal and is cut off during the other half of each cycle of said alternating signal; E. a capacitor coupled to said switching means for being charged when said electronic switching means is conducting and discharges when said switching means is not conducting; F. an electronic pulse forming circuit coupled to said capacitor for producing a pulse responsive to said capacitor charging to a predetermined level indicating that said amplitude of said multiphase alternating voltage has dropped below a predetermined level; and G. an indicator means coupled to said pulse forming means for being activated responsive to the amplitude of said multiphase voltage dropping below a predetermined level.

Claim 3

Dependent Claim 47 words

The voltage sensor as set forth in claim 1, wherein said trigger circuit includes: A. a pair of transistors coupled together for alternate conduction; and B. a resistor-capacitor network interposed between said pair of transistors for aiding in controlling the frequency that said pair of transistors conduct.

Claim 4

Dependent Claim 37 words

The voltage sensor as set forth in claim 1, wherein said electronic pulse forming includes a unijunctional transistor capable of being placed in a conducting state responsive to the charge on said capacitor reaching a predetermined level.

Claim 5

Dependent Claim 81 words

The vOltage sensor as set forth in claim 1, further comprising: A. a plurality of transformers corresponding in number to the phases of said multiphase voltage source; B. each phase of said voltage source being coupled to a primary winding of a respective transformer; and C. said means for rectifying said multiphase alternating voltage includes rectifiers interposed between said secondary windings of said transformers and said summing circuit means for rectifying the signals passing between said transformers and said summing circuit.

Claim 6

Dependent Claim 39 words

The voltage sensor as set forth in claim 1, further comprising a test circuit coupled to the input of said trigger circuit for simulating a drop in the level of said voltage source below said predetermined level when depressed.

Claim 7

Dependent Claim 37 words

The voltage sensor as set forth in claim 1, further comprising a latching relay interposed between said electronic pulse forming circuit and said indicator means for maintaining said indicator means in an activated state after being energized.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-03-22	1974-09-21	1975-03-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-03-22	1978-09-21	1979-03-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-03-22	1982-09-21	1983-03-23	$7700.00	Window Closed / Lapsed

Voltage dropout sensor

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