Three-phase motor control

Claim 2

A squirrel-cage induction motor having four motor terminals with a first winding connected between a first motor terminal and a second motor terminal, a second winding connected between said second motor terminal and a third motor terminal, a third winding connected between said third motor terminal and a fourth motor terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first motor terminal, the second wire of the said power supply connected to said third motor terminal, a first capacitor connected between said first motor terminal and said fourth motor terminal, and means for connecting a second capacitor between said second motor terminal and said third motor terminal.

Claim 3

A motor as in claim 1, wherein said motor is a three-phase motor, and wherein said first winding is a first motor phase winding, and wherein said second winding is a second motor phase winding, and wherein said third winding is a third motor phase winding, and means for connecting a third capacitor between said second motor terminal and said fourth motor terminal.

Claim 4

A motor as in claim 2, including first controllable-switch means for said means for connecting said first capacitor, second controllable-switch means for said means for connecting said second capacitor, and third controllable-switch means for said means for connecting said third capacitor.

Claim 5

A motor as in claim 3, wherein said first controllable-switch means is a first solid-state relay, and wherein said second controllable-switch means is a second solid-state relay, and wherein said third controllable-switch means is a third solid-state relay.

Claim 6

A motor as in claim 3, including first sensing means for sensing the voltage between said third motor terminal and said fourth motor terminal, and means responsive to said voltage to control said first controllable-switch means.

Claim 7

A motor as in claim 5, wherein said means responsive to said voltage is responsive to the magnitude of the alternating-current voltage.

Claim 8

A motor as in claim 5, wherein said means responsive to said voltage is responsive to the rate of change of the magnitude of the alternating-current voltage.

Claim 9

A motor as in claim 5, including additional means responsive to said voltage to also control said second and said third controllable switches.

Claim 10

A motor as in claim 5, including means responsive to the rate of change of the said voltage to control said first controllable switch.

Claim 11

A motor as in claim 5, including means responsive to the capacitor voltage across the first capacitor to control said first controllable switch.

Claim 12

A motor as in claim 5, including means responsive to the capacitor voltage across the said second capacitor to control said first controllable switch.

Claim 13

A motor as in claim 2, including first sensing means for sensing the voltage between said third motor terminal and said fourth motor terminal, and means responsive to said voltage to control said means for connecting said first capacitor.

Claim 14

A motor as in claim 2, including means responsive to the capacitor voltage across said first capacitor to control said means for connecting said first capacitor.

Claim 15

A motor as in claim 2, including sensing means responsive to the capacitor voltage across the said second capacitor, and means responsive to said sensing means to connect and disconnect said first capacitor.

Claim 16

A motor as in claim 2, including means to sense the voltage between the said third motor terminal and the said fourth motor terminal, and means responsive to said voltage to connect and disconnect said first capacitor.

Claim 17

A motor as in claim 2, including means to sense the voltage between the said third motor terminal and the said fourth motor terminal, and means responsive to said voltage to connect and disconnect said third capacitor.

Claim 18

A motor as in claim 2, including first solid-state relay means for said means for connecting said first capacitor, second solid-state relay means for said means for connecting said second capacitor, and third solid-state relay means for said means for connecting said third capacitor.

Claim 19

A motor as in claim 17, including first sensing means for sensing the voltage between said third motor terminal and said fourth motor terminal, and means responsive to said voltage to control said first solid-state relay means.

Claim 20

A motor as in claim 18, including means responsive to said voltage to control said second and said third solid-state relay means.

Claim 21

A motor as in claim 18, including means responsive to the rate of change of said voltage to control said first solid-state relay means.

Claim 22

A motor as in claim 18, including means responsive to the capacitor voltage across the said first capacitor to control said first solid-state relay means.

Claim 23

A motor as in claim 18, including means responsive to the capacitor voltage across the said second capacitor to control said first solid-state relay means.

Claim 24

A motor as in claim 2, including a starting circuit comprising a starting capacitor connected in series with a starting switch, said circuit being connected between said second motor terminal and said fourth motor terminal.

Claim 25

A motor as in claim 23, including means responsive to a current in one of the motor windings to control said starting switch.

Claim 26

A motor as in claim 23, including means responsive to a current in one of the said wires of the said power supply to control said starting switch.

Claim 27

A motor as in claim 23, including means for sensing the voltage on the said fourth motor terminal to control said starting switch.

Claim 28

A motor as in claim 2, including means for connecting said first capacitor and means responsive to the alternating current in said first motor phase winding to control the said means for connecting said first capacitor.

Claim 29

A motor as in claim 2, including means responsive to the alternating current in said first motor phase winding to control the said means for connecting said second capacitor.

Claim 30

A motor as in claim 2, including means responsive to the alternating current in said first motor phase winding to control the said means for connecting said third capacitor.

Claim 31

A three-winding three-phase motor, each winding having first and second winding terminals so polarized that a rotating flux in the motor air-gap will generate a first alternating voltage difference in the first winding from its first terminal to its second terminal which leads in phase by 120 electrical degrees a second generated alternating voltage difference in the second winding from its first terminal to its second terminal, and said second alternating voltage leads in phase by 120 electrical degrees a third generated alternating voltage difference in the third winding from its first terminal to its second terminal, a two-wire single-phase supply, a first wire of said supply connected to the first terminal of the first winding, the second wire of said supply connected to the first terminal of the second winding and also to the first terminal of the third winding, the second terminal of the first winding connected to the second terminal of the third winding, and a first capacitor connected between the second terminal of the second winding and the first wire of the said supply.

Claim 32

A three-winding three-phase motor, each winding having first and second winding terminals so polarized that a rotating flux in the motor air-gap will generate a first alternating voltage difference in the first winding from its first terminal to its second terminal which leads in phase by 120 electrical degrees a second generated alternating voltage difference in the second winding from its first terminal to its second terminal, and said second alternating voltage leads in phase by 120 electrical degrees a third generated alternating voltage difference in the third winding from its first terminal to its second terminal, a two-wire single-phase supply, a first wire of said supply connected to the first terminal of the first winding, the second wire of said supply connected to the first terminal of the second winding and also to the first terminal of the third winding, the second terminal of the first winding connected to the second terminal of the third winding, and a first capacitor connected between the second terminal of the second winding and the first wire of the said supply.

Claim 33

A three-phase motor as in claim 30 including a second capacitor connected between said second terminal of said first winding and said second terminal of said second winding.

Claim 36

The method as in claim 32 comprising generating a first alternating current which lags the voltage in said second winding by approximately 30 degrees, and introducing said first current into said second winding at said second winding terminal through said first capacitor, generating a second alternating current which lags said voltage in said second winding at said second winding terminal of said second winding through a second capacitor connected from the said second terminal of said first winding to the said second winding terminal of the said second winding, whereby the other two of the three windings of said motor are excited by their series connection between said first wire and the second wire of the said single-phase supply.

Claim 37

The method as in claim 32 where said first and second windings are in series across said two-wire single-phase supply including the step of exciting the second winding terminal of said second winding by a composite current generated by the sum of two different alternating currents with different phase angles.

Claim 38

A method as in claim 34, wherein one of said two different alternating currents leads the phase of the other of said two different alternating currents by thirty degrees.

Claim 39

A method as in claim 34, wherein the connection between the two windings in series is a motor terminal, and wherein one of said two different alternating currents is generated by said first capacitor connected to the first wire of the said supply, and wherein the other of said two different alternating currents is generated by a second capacitor connected to said motor terminal.

Claim 40

A method as in claim 34, wherein said composite current is generated with a resultant phase with respect to said third voltage difference in the said third motor winding so that the resultant flux field in the motor is approximately constant in magnitude and rotating at approximately constant angular velocity.

Claim 41

A squirrel-cage induction motor containing a rotating magnetic field, said motor having four terminals with a first winding connected between a first motor terminal and a second motor terminal, the internal magnetic polarity of said first winding from said first terminal to said second terminal with respect to said magnetic field having a first phase, a second winding connected between said second motor terminal and a third motor terminal, a second internal phase of said second winding from said second terminal to said third terminal with respect to said magnetic field, said second phase having a phase magnitude with respect to said first phase nominally lagging 60 degrees, and in operation more than 30 degrees and less than 90 degrees, a third winding connected between said third motor terminal and a fourth motor terminal, a third internal phase of said third winding from said third terminal to said fourth terminal with respect to said magnetic field, said third phase having a phase magnitude with respect to said second phase nominally lagging 60 degrees and in operation more than 30 degrees and less than 90 degrees, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, a first capacitor connected between said first motor terminal and said fourth motor terminal, and means for connecting a second capacitor between said second motor terminal and said third motor terminal.

Claim 42

A squirrel-cage induction motor containing a rotating magnetic field, said motor having four terminals with a first winding connected between a first motor terminal and a second motor terminal, the internal magnetic polarity of said first winding from said first terminal to said second terminal with respect to said magnetic field having a first phase, a second winding connected between said second motor terminal and a third motor terminal, a second internal phase of said second winding from said second terminal to said third terminal with respect to said magnetic field, said second phase having a phase magnitude with respect to said first phase nominally lagging 60 degrees, and in operation more than 30 degrees and less than 90 degrees, a third winding connected between said third motor terminal and a fourth motor terminal, a third internal phase of said third winding from said third terminal to said fourth terminal with respect to said magnetic field, said third phase having a phase magnitude with respect to said second phase nominally lagging 60 degrees and in operation more than 30 degrees and less than 90 degrees, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, a first capacitor connected between said first motor terminal and said fourth motor terminal, and means for connecting a second capacitor between said second motor terminal and said third motor terminal.

Claim 43

A three-phase induction motor with a first motor winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second motor terminal and said sixth motor terminal.

Claim 44

A three-phase induction motor with a first motor winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second motor terminal and said sixth motor terminal.

Claim 45

A motor as in claim 39, including a second capacitor connected between said second terminal and said fifth terminal.

Claim 46

A motor as in claim 43, including a second capacitor connected between said second terminal and said fifth terminal.

Claim 47

A motor as in claim 41, including a third capacitor connected between said fourth terminal and said sixth terminal.

Claim 48

A three-phase induction motor with a first motor winding having a designated first terminal and a fourth terminal, a second motor winding having a designated second terminal and a fifth terminal, a third motor winding having a designated third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said second terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said first terminal and said sixth terminal.

Claim 49

A three-phase induction motor with a first motor winding having a designated first terminal and a fourth terminal, a second motor winding having a designated second terminal and a fifth terminal, a third motor winding having a designated third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said second terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said first terminal and said sixth terminal.

Claim 50

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second winding connected between a second terminal and a fifth terminal, a third winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 51

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second winding connected between a second terminal and a fifth terminal, a third winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals four, five, and six were connected together then said terminals one, two and three would comprise a wye-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 52

A motor as in claim 44, including a second capacitor connected between said first terminal and said fourth terminal.

Claim 53

A motor as in claim 45, including a third capacitor connected between said fourth terminal and said sixth terminal.

Claim 54

A motor as in claim 46, wherein said third capacitor is a starting capacitor, and wherein the voltage between said third terminal and said sixth terminal is sensed to produce a control signal, and wherein said control signal controls the insertion and removal of the said third capacitor.

Claim 55

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals one and five were connected together, and if terminals three and four were connected together, and if terminals two and six were connected together, then terminals one, two and three would comprise a delta-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 56

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals one and five were connected together, and if terminals three and four were connected together, and if terminals two and six were connected together, then terminals one, two and three would comprise a delta-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 57

A motor as in claim 48, including a second capacitor connected between said second terminal and said fifth terminal.

Claim 58

A motor as in claim 49, including a third capacitor connected between said fourth terminal and said sixth terminal.

Claim 59

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals one and six were connected together, and if terminals two and four were connected together, and if terminals three and five were connected together then said terminals one, two and three would comprise a delta-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 60

A three-phase induction motor with a first winding connected between a first terminal and a fourth terminal, a second motor winding connected between a second terminal and a fifth terminal, a third motor winding connected between a third terminal and a sixth terminal, said windings polarized such that if said terminals one and six were connected together, and if terminals two and four were connected together, and if terminals three and five were connected together then said terminals one, two and three would comprise a delta-connected three-phase motor, an electrical connection of said fourth terminal to said fifth terminal, an electrical connection of said first terminal to said third terminal, a two-wire single-phase power supply, a first wire of the said power supply connected to said first terminal, the second wire of said power supply connected to said second terminal, and means for connecting a first capacitor between said second terminal and said sixth terminal.

Claim 61

A motor as in claim 51, including a second capacitor connected between said first terminal and said fourth terminal.

Claim 62

A motor as in claim 52, including a third capacitor connected between said fourth terminal and said sixth terminal.

Claim 63

A squirrel-cage induction motor having four motor terminals with a first winding connected between a first motor terminal and a second motor terminal, a second winding connected between said second motor terminal and a third motor terminal, a third winding connected between said third motor terminal and a fourth motor terminal, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, the voltage between said first motor terminal and said second motor terminal being a first voltage, the voltage between said second motor terminal and said third motor terminal being a second voltage, the voltage between said third motor terminal and said fourth motor terminal being a third voltage, the voltage between said first motor terminal and said fourth motor terminal being a fourth voltage, the magnitude of said fourth voltage being more than ten percent more than the magnitude of said second voltage, and a capacitor connected between said first motor terminal and said fourth motor terminal.

Claim 64

A squirrel-cage induction motor having four motor terminals with a first winding connected between a first motor terminal and a second motor terminal, a second winding connected between said second motor terminal and a third motor terminal, a third winding connected between said third motor terminal and a fourth motor terminal, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, the voltage between said first motor terminal and said second motor terminal being a first voltage, the voltage between said second motor terminal and said third motor terminal being a second voltage, the voltage between said third motor terminal and said fourth motor terminal being a third voltage, the voltage between said first motor terminal and said fourth motor terminal being a fourth voltage, the magnitude of said fourth voltage being more than ten percent more than the magnitude of said second voltage, and a capacitor connected between said first motor terminal and said fourth motor terminal.

Claim 65

A squirrel-cage induction motor having four motor terminals with a first winding connected between a first motor terminal and a second motor terminal, a second winding connected between said second motor terminal and a third motor terminal, a third winding connected between said third motor terminal and a fourth motor terminal, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, the voltage between said first motor terminal and said second motor terminal being a first voltage, the voltage between said second motor terminal and said third motor terminal being a second voltage, the voltage between said third motor terminal and said fourth motor terminal being a third voltage, the voltage between said first motor terminal and said fourth motor terminal being a fourth voltage, the magnitude of said fourth voltage being more than ten percent more than the magnitude of said third voltage, and a capacitor connected between said first motor terminal and said fourth motor terminal.

Claim 66

A squirrel-cage induction motor having four motor terminals with a first winding connected between a first motor terminal and a second motor terminal, a second winding connected between said second motor terminal and a third motor terminal, a third winding connected between said third motor terminal and a fourth motor terminal, a two-wire single-phase power supply, a first wire of said power supply connected to said first motor terminal, the second wire of said power supply connected to said third motor terminal, the voltage between said first motor terminal and said second motor terminal being a first voltage, the voltage between said second motor terminal and said third motor terminal being a second voltage, the voltage between said third motor terminal and said fourth motor terminal being a third voltage, the voltage between said first motor terminal and said fourth motor terminal being a fourth voltage, the magnitude of said fourth voltage being more than ten percent more than the magnitude of said third voltage, and a capacitor connected between said first motor terminal and said fourth motor terminal.

Claim 69

A method as in claim 56, wherein the phase of one of the said two different alternating currents leads the phase of the other of the said two different alternating currents by approximately thirty degrees.

Claim 70

A method as in claim 56, wherein one of the said two different alternating currents is generated by a capacitor connected to the first said wire of the said supply, and wherein the other of the said two different alternating currents is generated by a capacitor connected to the said second terminal of the said first winding.

Claim 71

A method as in claim 56, wherein said composite current contributes to the flux field in the motor so that the resultant flux field in the motor rotates at approximately constant angular velocity and is approximately constant in magnitude.

Claim 72

A three-phase motor with three terminals and a single-phase power supply with two lines, wherein the first line of the said power supply is connected to the first terminal of the said motor, the second line of the said power supply is connected to the second terminal of the said motor, an autotransformer with four taps, the first tap connected to the said first terminal, the second tap connected to the said second terminal, a first series circuit of a first capacitor and a first switch connected between the third tap of the said autotransformer and the third terminal of the said motor, and a second series circuit of a second capacitor and a second switch connected between the fourth tap of the said autotransformer and the third terminal of the said motor.

Claim 73

A three-phase motor with three terminals and a single-phase power supply with two lines, wherein the first line of the said power supply is connected to the first terminal of the said motor, the second line of the said power supply is connected to the second terminal of the said motor, an autotransformer with four taps, the first tap connected to the said first terminal, the second tap connected to the said second terminal, a first series circuit of a first capacitor and a first switch connected between the third tap of the said autotransformer and the third terminal of the said motor, and a second series circuit of a second capacitor and a second switch connected between the fourth tap of the said autotransformer and the third terminal of the said motor.

Claim 74

A motor as in claim 60, including a third series circuit of a third capacitor and a third switch connected between the third terminal of the said motor and the second tap of the said autotransformer.

Claim 75

A motor as in claim 60, including sensing the voltage on the said third terminal of the motor, and controlling the open and closed states of the said first switch responsive to the said sensed voltage.

Claim 76

A motor as in claim 60, including sensing the voltage on the said third terminal of the motor, and controlling the open and closed states of both of the said first switch and of the said second switch responsive to the said sensed voltage.

Claim 77

A motor as in claim 61, including sensing the voltage on the said third terminal of the motor, and controlling the open and closed states of the said first switch responsive to the said sensed voltage.

Claim 78

A motor as in claim 61, including sensing the voltage on the said third terminal of the motor, and controlling the open and closed states of the said first switch and of the said second switch and of the said third switch responsive to the said sensed voltage.

Claim 79

A motor as in claim 63, wherein the said sensed voltage is responsive to the motor shaft torque, and wherein the first and second switches are closed when the shaft torque is maximum and the sensed voltage is minimum.

Claim 80

A motor as in claim 63, wherein the said sensed voltage is responsive to the motor shaft torque, and wherein the first and second switches are open when the shaft torque is minimum and the sensed voltage is maximum.

Claim 81

A squirrel-cage electrical induction machine having four machine terminals with a first winding connected between a first machine terminal and a second machine terminal, a second winding connected between said second machine terminal and a third machine terminal, a third winding connected between said third machine terminal and a fourth machine terminal, a two-wire single-phase power system, a first wire of the said power system connected to said first machine terminal, the second wire of the said power system connected to said third machine terminal, and means for connecting a capacitor between said first machine terminal and said fourth machine terminal.

Claim 82

A squirrel-cage electrical induction machine having four machine terminals with a first winding connected between a first machine terminal and a second machine terminal, a second winding connected between said second machine terminal and a third machine terminal, a third winding connected between said third machine terminal and a fourth machine terminal, a two-wire single-phase power system, a first wire of the said power system connected to said first machine terminal, the second wire of the said power system connected to said third machine terminal, and means for connecting a capacitor between said first machine terminal and said fourth machine terminal.

Claim 83

An electrical machine as in claim 68, including means for connecting a second capacitor between said second machine terminal and one of the wires of the said single-phase power system.