Browse Prior Art Database

Line Voltage Fault Look Ahead Circuit

IP.com Disclosure Number: IPCOM000079514D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Clark, VR: AUTHOR [+3]

Abstract

This line voltage fault look-ahead circuit monitors the input line voltage, to determine if it has fallen below power line disturbance limits. If the input line voltage is removed, the circuit sends a signal to the devices using the power supply indicating that power is about to fail. The look-ahead capability is provided by insuring a definite decay time.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Line Voltage Fault Look Ahead Circuit

This line voltage fault look-ahead circuit monitors the input line voltage, to determine if it has fallen below power line disturbance limits. If the input line voltage is removed, the circuit sends a signal to the devices using the power supply indicating that power is about to fail. The look-ahead capability is provided by insuring a definite decay time.

In the figure the AC line input is applied to transformer 10. The output of transformer 10 is applied to control voltage block 20 and to time control voltage sense circuit 30. The time control voltage sense circuit 30 has a faster decay time than control voltage block 20. Voltage regulator 40 provides a reference voltage for comparator 60, which compares the reference voltage with the output of time control voltage sense circuit 30. Voltage regulator 50 provides supply voltage to comparator 60.

Comparator 60 generates an output signal when the voltage of time control voltage sense circuit 30 falls below the reference voltage provided by regulator
40. This output is applied to driver circuit 70 to de-energize the same. With driver 70 de-energized, normally-closed contacts in reed relay 80 are permitted to close and this provides signals at terminals 81 and 82, to indicate to the devices using the power supply that power at terminal 21 is about to fail.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]