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Browse Prior Art Database

Triac AC Converter

IP.com Disclosure Number: IPCOM000073649D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Farel, CA: AUTHOR [+2]

Abstract

Shown is a triac circuit for gating power from a three-phase supply to a three-phase load. When it is desired to gate the power to the load, the relays 10 and 12 are operative to close the circuit connected to the gate of each of the triacs 14 and 16. Capacitor 18 and resistor 20 form a commutation dV/dt suppression network. In addition, the charge on capacitor 18 is used to trigger the triac.

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Triac AC Converter

Shown is a triac circuit for gating power from a three-phase supply to a three-phase load. When it is desired to gate the power to the load, the relays 10 and 12 are operative to close the circuit connected to the gate of each of the triacs 14 and 16. Capacitor 18 and resistor 20 form a commutation dV/dt suppression network. In addition, the charge on capacitor 18 is used to trigger the triac.

Each triac and its associated triggering circuit operate in the following manner. When the triac current drops below its holding current value, the triac 14 switches off and the capacitor 18 starts to charge. The capacitor will continue to charge until the voltage across the capacitor exceeds the triggering level of the triac. At this point, the capacitor discharges into the gate of the triac 14 and turns the triac on. After the triac is turned on, the capacitor will no longer charge until the triac current again drops below the holding current for the triac on the next half-cycle. Thus, with the relay 10 closed, triac 14 is continually being gated on during the appropriate half-cycle.

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