Browse Prior Art Database

Zero Crossover Current Sensor

IP.com Disclosure Number: IPCOM000092195D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Smith, LA: AUTHOR

Abstract

Diodes 11 and 12 and pulse transformer 13 are arranged to provide a distinct pulse at zero crossover at all levels of current flowing in the circuit. The latter is particularly applicable for controlling the turn-on of silicon controlled rectifiers SCR's where it is frequently necessary to compensate for leading or lagging power factors. Current of sine waveform, curve 16, is rectified by SCR 20 switched by gate drive circuit 22 in accordance with a desired predetermined gating timing plan. Gate voltage generator 24 is arranged to produce a gating wave, curve 26, in accordance with that plan. This gating wave 26 is effective only at zero crossover time through the intermediary of And 28. Gating wave 26 is applied to one input of And 28.

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

Zero Crossover Current Sensor

Diodes 11 and 12 and pulse transformer 13 are arranged to provide a distinct pulse at zero crossover at all levels of current flowing in the circuit. The latter is particularly applicable for controlling the turn-on of silicon controlled rectifiers SCR's where it is frequently necessary to compensate for leading or lagging power factors. Current of sine waveform, curve 16, is rectified by SCR 20 switched by gate drive circuit 22 in accordance with a desired predetermined gating timing plan. Gate voltage generator 24 is arranged to produce a gating wave, curve 26, in accordance with that plan. This gating wave 26 is effective only at zero crossover time through the intermediary of And 28. Gating wave 26 is applied to one input of And 28. The sharp pulses, curve 30, at the secondary winding of transformer 13 are applied through amplifier 32 to the other terminal of And 28. The latter is thus effective only at zero current time.

1

Page 2 of 2

2

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