Cycloconverter motor system

Claim 2

A converter for supplying a polyphase AC induction motor from an AC source, comprising: a source of AC voltage, a polyphase AC induction motor, each phase winding of said AC induction motor comprised of a pair of windings conductively isolated from each other and from all other phase windings, a plurality of unidirectionally conductive switching means equal in number to the total number of windings, each switching means comprised of a plurality of controlled rectifiers and a plurality of diodes, each of said switching means having AC input terminals and a pair of DC output terminals, means connecting said switching means AC input terminals to said source of AC voltage, means connecting each of said windings across a respective pair of DC output terminals of said switching means, each phase winding having its pair of windings connected in a manner to provide oppositely directed magnetic fields when energized by DC voltage from their respective switching means, and control means connected to the controlled rectifiers of each switching means to sequentially switch said plurality of switching means whereby, each of said switching means sequentially provides unidirectional current to its respective winding in response to a control signal from said control means and said polyphase AC induction motor is provided polyphase AC voltage.

Claim 3

A converter for supplying AC voltage to a three-phase AC induction motor from a three phase AC source, comprising: a three-phase source of AC voltage, three supply conductors connected respectively with the three output terminals of said source of AC voltage, 18 diodes, 18 controlled rectifiers, each of said controlled rectifiers having its anode connected with the cathode of a respective diode to provide 18 serially connected diode-controlled rectifier pairs, said diode-controlled rectifier pairs grouped into six groups of three diode-controlled rectifier pairs, one of said diode-controlled rectifier pairs of each of said six groups having their anode-cathode junction connected with each of said three supply conductors such that each group of three diode-controlled rectifier pairs has one diode-controlled rectifier pair connected with each of said three supply conductors, a three-phase AC induction motor provided with two identical three-phase motor windings, each of the six-phase windings of said two identical three-phase motor Windings being conductively isolated from all other phase windings, each of said six-phase windings of said induction motor having one terminal connected with the three cathodes of the controlled rectifiers of a respective one of said groups of diode-controlled rectifier pairs and its other terminal connected with the three anodes of the diodes of that group, and a source of gate signals connected with the gate-cathode circuit of each of said controlled rectifiers, said source of gate signals sequentially switching the controlled rectifiers of each of the groups whereby, three-phase AC voltage having a frequency determined by the repetition frequency of said source of gate signals is applied to said induction motor.

Claim 4

A converter for supplying AC voltage to a three-phase AC induction motor from a three phase AC source, comprising: a three-phase source of AC voltage, three supply conductors connected respectively with the three output terminals of said source of AC voltage, 18 diodes, 18 controlled rectifiers, each of said controlled rectifiers having its anode connected with the cathode of a respective diode to provide 18 serially connected diode-controlled rectifier pairs, said diode-controlled rectifier pairs grouped into six groups of three diode-controlled rectifier pairs, one of said diode-controlled rectifier pairs of each of said six groups having their anode-cathode junction connected with each of said three supply conductors such that each group of three diode-controlled rectifier pairs has one diode-controlled rectifier pair connected with each of said three supply conductors, a three-phase AC induction motor provided with two identical three-phase motor windings, each of the six-phase windings of said two identical three-phase motor Windings being conductively isolated from all other phase windings, each of said six-phase windings of said induction motor having one terminal connected with the three cathodes of the controlled rectifiers of a respective one of said groups of diode-controlled rectifier pairs and its other terminal connected with the three anodes of the diodes of that group, and a source of gate signals connected with the gate-cathode circuit of each of said controlled rectifiers, said source of gate signals sequentially switching the controlled rectifiers of each of the groups whereby, three-phase AC voltage having a frequency determined by the repetition frequency of said source of gate signals is applied to said induction motor.