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Polyphase Zero Controlled Electronic Switch

IP.com Disclosure Number: IPCOM000093543D
Original Publication Date: 1967-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Clark, MJ: AUTHOR

Abstract

The three-phase power switching circuit couples power to a delta-connected load Ra, Rb, and Rc with minimum switching noise. High power controlled rectifiers A, B, and C and their associated diodes Da, Db, and Dc couple line voltage to the load while the switch S is closed.

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Polyphase Zero Controlled Electronic Switch

The three-phase power switching circuit couples power to a delta-connected load Ra, Rb, and Rc with minimum switching noise. High power controlled rectifiers A, B, and C and their associated diodes Da, Db, and Dc couple line voltage to the load while the switch S is closed.

Rectifier A is turned on when line La is positive with respect to line Lb or Lc over a circuit including resistor R1, diodes Z1 and D1, resistor R2, load Ra or Rc and diode Db or Dc. Similarly, rectifiers B and C are energized when lines Lb and Lc are positive with respect to one of the other lines.

Each rectifier A, 8, and C turns off only when the voltage across its anode- cathode junction is approximately zero, thus minimizing noise on turnoff. Control circuits assure turnon of A, B, and C only when their respective line voltages are at approximately zero, thus minimizing turnon noise.

When S is off, contacts S1, S2, and S3 close. Low power rectifiers F, G, and H prevent energization of A, B, and C. With S off and La positive with respect to Lb, F is turned on via diode D2, resistor R3, S1 and R1. D2 and F short-circuit the turnon circuit of A. When La is positive with respect to Lc, diode D4, R3, S1 and R1 cause turnon of F.

Similar circuits cause turnon of G and H when their lines Lb and Lc are positive with respect to one of the other lines. If S closes when F, G or H is energized, the latter remain energized until the anode-cathode voltage rea...