Browse Prior Art Database

Three Phase Motor Control

IP.com Disclosure Number: IPCOM000090981D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Gillingham, P: AUTHOR [+2]

Abstract

To control a three-phase load 10, a pair of Triac semiconductor switches 12 and 14 is turned on at zero voltage, requiring a gate voltage in phase, or 180 degrees out of phase, with the anode voltage. If both Triacs are off, gate-to-anode voltages applied sequentially at the zero voltage point to switches 12 and 14 cause the five-element Triacs to turn on, independent of phase rotation. Divider resistors 16 and 18 are of equal value and resistors 20 and 22 are also equal in value. During the Run mode, the gate-to-anode phase relationship is maintained. For turnoff, the gate is open or off, allowing the Triacs to turn off when the holding current drops below the minimum.

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

Three Phase Motor Control

To control a three-phase load 10, a pair of Triac semiconductor switches 12 and 14 is turned on at zero voltage, requiring a gate voltage in phase, or 180 degrees out of phase, with the anode voltage. If both Triacs are off, gate-to- anode voltages applied sequentially at the zero voltage point to switches 12 and 14 cause the five-element Triacs to turn on, independent of phase rotation. Divider resistors 16 and 18 are of equal value and resistors 20 and 22 are also equal in value. During the Run mode, the gate-to-anode phase relationship is maintained. For turnoff, the gate is open or off, allowing the Triacs to turn off when the holding current drops below the minimum. This circuit arrangement enables automatic turning on, in proper sequence, of two or more phases of a three-phase supply, and then shifting control gate phase to maintain the phase relationship between gate voltage and anode current. The use of this circuit can be applied to polyphase circuits. Its use is not restricted to Triacs alone, but can be adapted to any solid state control device.

1

Page 2 of 2

2

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