FRANK J PRINES
Engineers in Murrysville, PA

5585758, Dec 17, 1996

Jun 29, 1994

8/267860

Frank J. Prines - Murrysville PA
Ray S. Kemerer - Monroeville PA
Martin I. Norman - Monroeville PA

Electric Power Research Institute, Inc. - Palo Alto CA

H03K 386, H01F 2700

327438

A current source gate drive circuit for simultaneous firing of a set of series or parallel thyristors is described. The circuit includes two current loops, each of which serves as a current transformer primary. Electrically insulating tubes enclose the current loops. Current transformer cores, around which are wound a certain number of secondary turns, surround the current loops, thus magnetically coupling the primary current of the current transformer to the secondary turns. Thyristor gate driver circuits are electrically coupled to the current transformer cores. Each of the thyristor gate driver circuits receives and rectifies ac current signals from the current loops and forms a current pulse train firing signal. Each thyristor gate driver circuit has a corresponding thyristor that is fired by the current pulse train firing signal. The thyristors operate at a high voltage, but are electrically isolated from the current loops by the insulating tubes.

4257092, Mar 17, 1981

Dec 13, 1978

5/968950

Frank J. Prines - Murrysville PA
Thomas C. Matty - North Huntingdon Township, Westmoreland County PA
James H. Franz - Murrysville PA

Westinghouse Electric Corp. - Pittsburgh PA

H02M 332, H02P 728

363124

A direct current motor power controlling chopper apparatus is disclosed which determines the operational speed of one or more traction motors propelling a passenger vehicle along a track. The speed of the motor is established by changing the ON and OFF conduction ratio or duty cycle relationship of a thyristor switch device to determine the field current and the armature voltage of that motor. The present apparatus can provide a greater controlled range of motor speeds including a lower minimum OFF operation and a full ON capacity. In addition, the present apparatus provides greater reliability due to less thermal stress on the thyristor switch devices and fewer circuit elements required to provide an improved motor current control operation.