公开(公告)号：CA1248583A

公开(公告)日：1989-01-10

申请号：CA470452

申请日：1984-12-18

Applicant: IBM

Inventor： COMMANDER ROBERT D ,  FENTON BRIAN P ,  RAMAGE JOHN G

IPC: H02M7/537 ,  H02M7/5387 ,  H03K17/691 ,  H02M3/335 ,  H02P6/02 ,  H02P1/18

Abstract: A power switching circuit for switching power repetitively to a load at a relatively low frequency employs a power switching device which is driven across an isolating transformer interface. The drive signals are high frequency pulse signals which are modulated with the low frequency switching information, the modulations being detected in the secondary circuit of the transformer. Such an arrangement affords isolated driving with fast switching edges and requires only a small transformer. Power for the detection circuit is derived by rectification of the high frequency signals induced in the transformer secondary.

公开(公告)号：CA1180376A

公开(公告)日：1985-01-02

申请号：CA385479

申请日：1981-09-09

Applicant: IBM

Inventor： DAVY JOHN C ,  FENTON BRIAN P ,  RAMAGE JOHN G

IPC: H02P1/42 ,  G09G1/04 ,  G09G1/16 ,  H04N3/16 ,  H04N5/445

Abstract: MOTOR CONTROL SYSTEM FOR A SINGLE PHASE INDUCTION MOTOR A single phase induction motor control system employs mains assisted starting and runs at higher than mains fre quency from an electronically generated inverter supply. This inverter supply is employed to provide an out of phase mains frequency signal to the run winding during starting in order to create the rotating magnetic field needed to start the motor. After the motor has started, the mains supply is disconnected from the start winding and the inverter supply frequency is increased gradually to a final value corresponding to the desired operating speed. In this system no phase shifting capacitors are needed to provide the out of phase starting voltage and the run winding can be optimized for running conditions.