Electronic speed control of three-phase motor - in delta connection has triac for control purposes each delta arm

摘要

The delta connection is provided with control circuits which tap the synchronizing voltage directly via the triac. The control circuits are connected by signal lines to a common control signal generator via electrically isolating signal couplings. The base of two triacs is at a common phase of the three-phase system. The control signal lines of both control circuits are connected to each other and to the control signal generator via a common signal couplings. One motor winding is inserted in each of three arms, which link the phase connections, and connected in series to a triac.