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Three Phase Trigger Generator

IP.com Disclosure Number: IPCOM000094535D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Kekas, DH: AUTHOR [+2]

Abstract

This circuit senses a transient on any line 5, 6 and 7 of a three-phase electrical power system. The circuit produces a signal at its output terminals 8 and 9. The signal triggers an oscilloscope to display the transient waveform of the line which appears at circuit output terminals 10, 11 and 12. The circuit for one phase is shown in detail. Identical circuits for the other two phases are outlined.

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Three Phase Trigger Generator

This circuit senses a transient on any line 5, 6 and 7 of a three-phase electrical power system. The circuit produces a signal at its output terminals 8 and 9. The signal triggers an oscilloscope to display the transient waveform of the line which appears at circuit output terminals 10, 11 and 12. The circuit for one phase is shown in detail. Identical circuits for the other two phases are outlined.

Each phase circuit has a step attenuator switch 13 for adapting the circuit to different power line voltages. There is also a potentiometer 14 for establishing the minimum amplitude transient to which the circuit is to respond. Delay line 15 of discrete capacitors and resistors is connected at one end 16 to receive the power Line waveform at potentiometer 14. Delay 15 has the appropriate length to hold exactly a half cycle or an odd multiple of the power line waveform. Thus, the voltage at end 17 is a pretransient reference for the waveform at end 16. A difference ~n voltage at ends 16 and 17 signifies a transient on the associated line.

A network of resistors and a capacitor connects ends 16 and 17 to produce the difference voltage at point 19. A circuit of diodes 21 for suppressing high magnitude line voltages couples point 19 to a circuit of transistors. This rectifies and amplifies the transient wave form and produces a triggering signal across terminals 8 and 9. In this circuit, transistor T1 is connected to produce a positive going...