Patent US3821620A successfully refreshed from Google Patents.
US3821620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric induction motor and control system
Assignee: Emerson Electric Co
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Filing: 1972-05-15
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Granted: 1974-06-28
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Expires: 1992-05-15
Abstract
Abstract A two phase electric induction motor including a rotary phase converter for providing the second phase of power, a fan on the shaft of the rotary phase converter for cooling the motor independent of the shaft speed of the motor, and a speed control powered by the output of the rotary phase converter for controlling the firing angles of triacs in series with the first and second windings of the motor. The speed of the motor is sensed by an electronic tachometer including a pair of induction coils which are electrically coupled to each other across an air gap to form a variable feedback system for a tuned high frequency amplifier. A circuit board disc carried by the motor shaft includes 36 peripheral copper plates which, as they pass through the air gap between the inductors, disturb the coupling between the inductors and produce an output envelope of high frequency AC. The speed control produces a ramp voltage having a slope dependent on a speed control setting and a duration which extends until cut off by a signal from the speed sensor. The ramp voltage is compared with a reference voltage, the excess voltage is converted to a DC level, buffered and fed to a timing logic circuit which increases or decreases the firing angle of the control triacs in accordance with the magnitude and sign of the error signal. The motor system is capable of exerting full torque at virtually any shaft speed, will maintain its shaft speed regardless of changes in shaft load, and will withstand extended service in a locked rotor condition. Other forms of tachometers utilizing a speed sensitive shutter positioned between a light source and a light sensing electronic component, and other speed control systems are also disclosed.
Inventors
- 👤 A Lindberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:20
CPC Classifications
H; H02; H02K; H02K17/00; H02K17/02; H02K17/34; H02P; H02P25/00; H02P25/02; H02P25/04
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
138 words
An electric motor system adapted to operate from a single phase AC power source comprising phase converter means, adapted to be energized by said single phase power source, for providing a polyphase power source, said phase converter means comprising a rotary phase converter; a polyphase induction motor having first and second windings electrically connected to said polyphase power source, rotors of said rotary phase converter and said polyphase electric motor rotating mechanically independent of each other; cooling means driven by the rotor of said rotary phase converter for cooling said polyphase motor independent of the rotor speed of said polyphase motor; and control means for supplying power to said polyphase motor, and control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding.
Claim 2
Dependent Claim
138 words
An electric motor system adapted to operate from a single phase AC power source comprising phase converter means, adapted to be energized by said single phase power source, for providing a polyphase power source, said phase converter means comprising a rotary phase converter; a polyphase induction motor having first and second windings electrically connected to said polyphase power source, rotors of said rotary phase converter and said polyphase electric motor rotating mechanically independent of each other; cooling means driven by the rotor of said rotary phase converter for cooling said polyphase motor independent of the rotor speed of said polyphase motor; and control means for supplying power to said polyphase motor, and control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding.
Claim 3
Dependent Claim
47 words
The electric motor system of claim 1 including speed sensing means for sensing the rotor speed of said polyphase motor, said control means comprising speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value.
Claim 4
Dependent Claim
72 words
The electric motor system of claim 2 wherein said speed sensing means comprise discrete means carried by said polyphase motor rotor, amplifier means having an input and an output, and variable feedback means electrically connected between said input and output for varying the feedback of said amplifier means in response to movement of one of said discrete means past said feedback means, said amplifier output being electrically connected to said control means.
Claim 5
Dependent Claim
95 words
The electric motor system of claim 2 wherein said speed control means comprise means for generating a ramp voltage, means responsive to said speed sensing means for terminating said ramp in response to rotation of said polyphase motor rotor through a predetermined angle, error sensing means for comparing the ramp height with a reference voltage and producing an error signal dependent on the relative magnitudes of said ramp height and said reference voltage, and timing logic means for controlling the ''''on'''' time of said gating means in response to the magnitude of said error signal.
Claim 6
Dependent Claim
20 words
The electric motor system of claim 4 including manually operable speed setting means for varying the slope of said ramp.
Claim 7
Dependent Claim
91 words
The electric motor system of claim 2 wherein said speed sensing means comprise first and second detector means coupled to each other through an air gap to proDuce an output signal; shutter means adapted to be moved in said air gap for varying the coupling of said first and second detector means, hence the magnitude of said output signal; and centrifugal governor means carried by said rotor of said polyphase motor for varying the position of said shutter, hence the magnitude of said output signal with changes in said rotor speed.
Claim 8
Dependent Claim
22 words
The electric motor system of claim 6 wherein said first and second detector means comprise a light source and a light-sensitive transistor.
Claim 9
Dependent Claim
62 words
The electric motor system of claim 1 wherein said cooling means comprise a fan carried by the rotor of said rotary phase converter, said fan being positioned axially between a stator of said phase converter and a stator of said polyphase motor, at least a part of said control means being positioned between said fan and said stator of said polyphase motor.
Claim 10
Dependent Claim
26 words
The electric motor system of claim 1 wherein said control means supplies power to said polyphase motor only when said rotary phase converter provides an output.
Claim 11
Dependent Claim
131 words
An electric motor system adapted to operate from a single phase power source comprising phase converter means, adapted to be energized by said single phase power source, for providing a polyphase power source, said phase converter means comprising a rotary phase converter; a polyphase induction motor having first and second windings electrically connected to said polyphase power source, rotors of said rotary phase converter and said polyphase electric motor rotating mechanically independent of each other; and control means for supplying power to said polyphase motor, said control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding for controlling the part of each cycle of said polyphase power applied to said first and second winding respectively.
Claim 12
Dependent Claim
131 words
An electric motor system adapted to operate from a single phase power source comprising phase converter means, adapted to be energized by said single phase power source, for providing a polyphase power source, said phase converter means comprising a rotary phase converter; a polyphase induction motor having first and second windings electrically connected to said polyphase power source, rotors of said rotary phase converter and said polyphase electric motor rotating mechanically independent of each other; and control means for supplying power to said polyphase motor, said control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding for controlling the part of each cycle of said polyphase power applied to said first and second winding respectively.
Claim 13
Dependent Claim
47 words
The electric motor system of claim 10 including speed sensing means for sensing the rotor speed of said polyphase motor, said control means comprising speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value.
Claim 14
Dependent Claim
35 words
The electric motor system of claim 10 wherein said control means supply power to said polyphase motor only when said rotary phase converter provides an output, said control means being energized by said phase converter.
Claim 15
Dependent Claim
231 words
An electric motor system adapted to operate from a single phase AC power source comprising rotary phase converter means, adapted to be energized by said single phase power source, for providing a two phase power source, said rotary phase converter being a permanent split capacitor motor including a main winding electrically connected between a first side and a second side of said single phase power source, and a capacitor and an aux winding electrically connected in series between said first and said second sides of said single phase power source, a first phase of said two phase power source being across said main winding from said first side to said second side of said single phase power source, a second phase of said two phase power source being across said aux winding from a point electrically between said capacitor and said aux winding to said second side of said single phase power source; a two phase induction motor having a first winding connected across said first phase and a second winding connected across said second phase, rotors of said rotary phase converter and said two phase motor rotating mechanically independent of each other; and control means for supplying power to said two phase motor, said control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding.
Claim 16
Dependent Claim
231 words
An electric motor system adapted to operate from a single phase AC power source comprising rotary phase converter means, adapted to be energized by said single phase power source, for providing a two phase power source, said rotary phase converter being a permanent split capacitor motor including a main winding electrically connected between a first side and a second side of said single phase power source, and a capacitor and an aux winding electrically connected in series between said first and said second sides of said single phase power source, a first phase of said two phase power source being across said main winding from said first side to said second side of said single phase power source, a second phase of said two phase power source being across said aux winding from a point electrically between said capacitor and said aux winding to said second side of said single phase power source; a two phase induction motor having a first winding connected across said first phase and a second winding connected across said second phase, rotors of said rotary phase converter and said two phase motor rotating mechanically independent of each other; and control means for supplying power to said two phase motor, said control means including first gating means electrically connected in series with said first winding and second gating means electrically connected in series with said second winding.
Claim 17
Dependent Claim
48 words
The electric motor system of claim 13 including speed sensing means for sensing the rotor speed of said two phase motor, said control means comprising speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value.
Claim 18
Dependent Claim
29 words
The electric motor system of claim 14 wherein the turns ratio of said aux winding to said main winding of said rotary phase converter is at least about two.
Claim 19
Dependent Claim
149 words
An electric motor system adapted to operate from a primary AC power source comprising phase converter means, adapted to be energized by said AC power source, for providing a secondary polyphase power source, said phase converter means comprising a first polyphase induction motor having first and second windings; a second polyphase induction motor having first and second windings electrically connected to said secondary polyphase power source, rotors of said first motor and said second motor rotating mechanically independent of each other; and control means for supplying power to said second motor, said control means including first gating means electrically connected in series with said first winding of said second motor and second gating means electrically connected in series with said second winding of said second motor for controlling the part of each cycle of said polyphase power applied respectively to said first and second windings of said second motor.
Claim 20
Dependent Claim
149 words
An electric motor system adapted to operate from a primary AC power source comprising phase converter means, adapted to be energized by said AC power source, for providing a secondary polyphase power source, said phase converter means comprising a first polyphase induction motor having first and second windings; a second polyphase induction motor having first and second windings electrically connected to said secondary polyphase power source, rotors of said first motor and said second motor rotating mechanically independent of each other; and control means for supplying power to said second motor, said control means including first gating means electrically connected in series with said first winding of said second motor and second gating means electrically connected in series with said second winding of said second motor for controlling the part of each cycle of said polyphase power applied respectively to said first and second windings of said second motor.
Claim 21
Dependent Claim
35 words
The electric motor system of claim 16 including cooling means driven by the shaft of said first induction motor for cooling said second induction motor independent of the rotor speed of said second induction motor.
Claim 22
Dependent Claim
23 words
The electric motor system of claim 17 wherein said cooling means comprise a fan carried by a rotor of said first induction motor.
Claim 23
Dependent Claim
39 words
The electric motor system of claim 18 wherein rotors of said first and second induction motors are coaxial, said fan being positioned axially between a stator of said first induction motor and a stator of said second induction motor.
Claim 24
Dependent Claim
28 words
The electric motor system of claim 19 wherein at least a part of said control means are positioned between said fan and said stator of said second motor.
Claim 25
Dependent Claim
47 words
The electric motor system of claim 16 including speed sensing means for sensing the rotor speed of said polyphase motor, said control means comprising speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value.
Claim 26
Dependent Claim
78 words
The electric motor system of claim 21 wherein said speed sensing means comprise discrete means carried by, and fixed with respect to, said first induction motor rotor, amplifier means having an input and an output, and variable feedback means electrically connected between said input and output for varying the feedback of said amplifier means in response to movement of one of said discrete means past said feedback means, said amplifier output being electrically connected to said control means.
Claim 27
Dependent Claim
101 words
The electric motor system of claim 21 wherein said speed sensing means comprise a pair of reactive means coupled to each other through an air gap, a first circuit including one of said reactive means, a second circuit including the other of said reactive means, a sensing means for sensing a disturbance of said coupling of said reactive means, and discrete means carried by, and fixed with respect to, said first induction motor rotor, said discrete means being positioned for movement into and out of said air gap when said polyphase shaft rotates, for disturbing said coupling of said reactive means.
Claim 28
Dependent Claim
41 words
The electric motor system of claim 23 wherein said first and second circuits are oscillator circuits, and said sensing means comprise an amplifier, said first and second circuits being connected across said amplifier to form a variable feedback for said amplifier.
Claim 29
Dependent Claim
35 words
The electric motor system of claim 24 wherein said sensing means further comprise means for detecting the end of a burst of pulses through said amplifier and for producing a control signal in response thereto.
Claim 30
Dependent Claim
96 words
The electric motor system of claim 21 wherein said speed control means compRise means for generating a ramp voltage, means responsive to said speed sensing means for terminating said ramp in response to rotation of said rotor of said second motor through a predetermined angle, error sensing means for comparing the ramp height with a reference voltage and producing an error signal dependent on the relative magnitudes of said ramp height and said reference voltage, and timing logic means for changing the ''''on'''' time of said gating in response to the magnitude of said error signal.
Claim 31
Dependent Claim
21 words
The electric motor system of claim 26 including speed setting means, said speed setting means varying the slope of said ramp.
Claim 32
Dependent Claim
33 words
The electric motor system of claim 27 wherein said error sensing means further comprise variable gain means for relatively increasing the magnitude of said error signal as the motor speed setting is increased.
Claim 33
Dependent Claim
92 words
The electric motor system of claim 21 wherein said speed sensing means comprise first and second detector means coupled to each other through an air gap to produce an output signal; shutter means adapted to be moved in said air gap for varying the coupling of said first and second detector means, hence the magnitude of said output signal; and centrifugal governor means carried by said rotor of said second induction motor for varying the position of said shutter, hence the magnitude of said output signal with changes in said rotor speed.
Claim 34
Dependent Claim
22 words
The electric motor system of claim 29 wherein said first and second detector means comprise a light source and a light-sensitive transistor.
Claim 35
Dependent Claim
28 words
The electric motor system of claim 23 wherein said phase converter means provides a two phase power source and said second induction motor is a two phase motor.
Claim 36
Dependent Claim
24 words
The electric motor system of claim 31 including reversing switch means for reversing the excitation connections of one of said first and second windings.
Claim 37
Dependent Claim
96 words
The electric motor system of claim 31 wherein said AC power source is a three phase source, said first winding of said first induction motor being electrically connected between a first and third phase of said AC power source and said second winding of said first induction motor being connected between a second phase of said AC power source and a center tap on said first winding, said two phase power source including a first connection between said first phase and said third phase, and a second connection between said second phase and said center tap.
Claim 38
Dependent Claim
182 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor, and speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value, said speed sensing means comprising amplifier means having an input and an output, and variable feedback means electrically connected between said input and output, said feedback means comprising first means electrically connected to said input, second means electrically connected to said output, and a plurality of discrete means carried by said rotor for providing a variable coupling between said first means and said second means and thus for varying the feedback of said amplifier means in response to movement of one of said discrete means past said feedback means, said amplifier output being electrically connected to said speed control means.
Claim 39
Dependent Claim
182 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor, and speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a preselected value, said speed sensing means comprising amplifier means having an input and an output, and variable feedback means electrically connected between said input and output, said feedback means comprising first means electrically connected to said input, second means electrically connected to said output, and a plurality of discrete means carried by said rotor for providing a variable coupling between said first means and said second means and thus for varying the feedback of said amplifier means in response to movement of one of said discrete means past said feedback means, said amplifier output being electrically connected to said speed control means.
Claim 40
Dependent Claim
161 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor, and speed control means responsive to said speed sensing means for controLling said gating means to maintain said rotor speed at a preselected value, said speed sensing means comprising a pair of reactive means coupled to each other through an air gap, a first circuit including one of said reactive means, a second circuit including the other of said reactive means, sensing means for sensing a disturbance of said coupling of said reactive means, and discrete means carried by said rotor, positioned for movement into and out of said air gap when said rotor rotates, for disturbing said coupling of said reactive means.
Claim 41
Dependent Claim
161 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor, and speed control means responsive to said speed sensing means for controLling said gating means to maintain said rotor speed at a preselected value, said speed sensing means comprising a pair of reactive means coupled to each other through an air gap, a first circuit including one of said reactive means, a second circuit including the other of said reactive means, sensing means for sensing a disturbance of said coupling of said reactive means, and discrete means carried by said rotor, positioned for movement into and out of said air gap when said rotor rotates, for disturbing said coupling of said reactive means.
Claim 42
Dependent Claim
43 words
The electric motor system of claim 35 wherein said first and second circuits are high frequency oscillator circuits, and said sensing means comprise an amplifier, said first and second circuits being connected across said amplifier to form a variable feedback for said amplifier.
Claim 43
Dependent Claim
33 words
The electric motor system of claim 36 wherein said sensing means further comprise means for detecting the end of a pulse train through said amplifier and producing a control signal in response thereto.
Claim 44
Dependent Claim
200 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor and speed control means responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value, said speed control means comprising means for generating a ramp voltage, means responsive to said speed sensing means for terminating said ramp in response to rotation of said motor shaft through a predetermined angle, error sensing means for comparing the height of each ramp with a reference voltage and producing an error signal for each said ramp, said error signal being dependent on the height of said ramp relative to said reference voltage, sample and hold means for holding a signal dependent on the magnitude of only the last generated said error signal, and timing logic means for controlling the ''''on'''' time of said gating means in response to the magnitude of said sample and hold means signal.
Claim 45
Dependent Claim
200 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor and speed control means responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value, said speed control means comprising means for generating a ramp voltage, means responsive to said speed sensing means for terminating said ramp in response to rotation of said motor shaft through a predetermined angle, error sensing means for comparing the height of each ramp with a reference voltage and producing an error signal for each said ramp, said error signal being dependent on the height of said ramp relative to said reference voltage, sample and hold means for holding a signal dependent on the magnitude of only the last generated said error signal, and timing logic means for controlling the ''''on'''' time of said gating means in response to the magnitude of said sample and hold means signal.
Claim 46
Dependent Claim
22 words
The electric motor system of claim 38 including variable speed setting means, said speed setting means varying the slope of said ramp.
Claim 47
Dependent Claim
67 words
The electric motor system of claim 38 wherein said motor is a polyphase motor having first and second main windings, a first source of alternating power and a second source of alternating power out of phase with said first source, said gating means being electrically connected in series with said first source and said first winding and in series with said second source and said second winding.
Claim 48
Dependent Claim
84 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising sensing means for producing a signal in response to rotation of the rotor through a predetermined angle, means for producing a voltage ramp, means responsive to said signal for terminating said voltage ramp, and means including sample and hold means responsive to the height of only the last generated voltage ramp for controlling said rotor speed.
Claim 49
Dependent Claim
84 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising sensing means for producing a signal in response to rotation of the rotor through a predetermined angle, means for producing a voltage ramp, means responsive to said signal for terminating said voltage ramp, and means including sample and hold means responsive to the height of only the last generated voltage ramp for controlling said rotor speed.
Claim 50
Dependent Claim
172 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor and speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a variable preselected value, said speed control means comprising means for generating a first error signal substantially proportional to the ratio between the speed sensed by the speed sensing means and the preselected speed valUe; amplifier means responsive to said first error signal for producing a second error signal; variable gain means for increasing the gain of said amplifier means in response to an increase in said preselected speed value; and timing logic means for controlling the ''''on'''' time of said gating means in response to the magnitude of said second error signal.
Claim 51
Dependent Claim
172 words
An electric motor system including an AC induction motor and a control system for maintaining the rotor speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the rotor speed of said motor and speed control means responsive to said speed sensing means for controlling said gating means to maintain said rotor speed at a variable preselected value, said speed control means comprising means for generating a first error signal substantially proportional to the ratio between the speed sensed by the speed sensing means and the preselected speed valUe; amplifier means responsive to said first error signal for producing a second error signal; variable gain means for increasing the gain of said amplifier means in response to an increase in said preselected speed value; and timing logic means for controlling the ''''on'''' time of said gating means in response to the magnitude of said second error signal.
Claim 52
Dependent Claim
165 words
An electric motor system including an AC induction motor and a control system for maintaining the shaft speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the shaft speed of said motor, and speed control means responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value, said speed sensing means comprising first and second detector means coupled to each other through an air gap to produce an output signal; shutter means adapted to be moved in said air gap for varying the coupling of said first and second detector means, hence the magnitude of said output signal; and centrifugal governor means carried by said rotor of said polyphase motor for varying the position of said shutter, hence the magnitude of said output signal with changes in said rotor speed.
Claim 53
Dependent Claim
165 words
An electric motor system including an AC induction motor and a control system for maintaining the shaft speed of the AC induction motor at a preselected value comprising gating means for controlling the part of each cycle of alternating power supplied to a winding of said motor, speed sensing means for sensing the shaft speed of said motor, and speed control means responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value, said speed sensing means comprising first and second detector means coupled to each other through an air gap to produce an output signal; shutter means adapted to be moved in said air gap for varying the coupling of said first and second detector means, hence the magnitude of said output signal; and centrifugal governor means carried by said rotor of said polyphase motor for varying the position of said shutter, hence the magnitude of said output signal with changes in said rotor speed.
Claim 54
Dependent Claim
22 words
The electric motor system of claim 43 wherein said first and second detector means comprise a light source and a light-sensitive transistor.
Claim 55
Dependent Claim
160 words
An electric motor system adapted to operate from a three phase AC power source comprising a three phase motor having three windings, a first of said windings being electrically connected between a first of said phases and a second of said phases, a second of said windings being electrically connected between said second phase and a third of said phases, and a third of said windings being connected between said third phase and said first phase; gating means for controlling the part of each cycle of power applied to each of said windings, said gating means comprising a first solid state switch electrically connected in series between said first winding and said second phase, a second solid state switch electrically connected between said second winding and said third phase, and a third solid state switch electrically connected between said third winding and said first phase; and control means for controlling the ''''on'''' time of each of said solid state switches.
Claim 56
Dependent Claim
160 words
An electric motor system adapted to operate from a three phase AC power source comprising a three phase motor having three windings, a first of said windings being electrically connected between a first of said phases and a second of said phases, a second of said windings being electrically connected between said second phase and a third of said phases, and a third of said windings being connected between said third phase and said first phase; gating means for controlling the part of each cycle of power applied to each of said windings, said gating means comprising a first solid state switch electrically connected in series between said first winding and said second phase, a second solid state switch electrically connected between said second winding and said third phase, and a third solid state switch electrically connected between said third winding and said first phase; and control means for controlling the ''''on'''' time of each of said solid state switches.
Claim 57
Dependent Claim
121 words
An electric motor system adapted to operate from a three phase AC power source comprising phase converter means for converting said three phase power to two phase power, a two phase motor electrically connected to said phase converter means, and control means electrically connected between said phase converter output and said two phase electric motor, said control means including gating means for controlling the part of each cycle of said two phase power applied to each winding of said two phase electric motor, speed sensing means for sensing the shaft speed of said two phase electric motor, and speed control menas responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value.
Claim 58
Dependent Claim
121 words
An electric motor system adapted to operate from a three phase AC power source comprising phase converter means for converting said three phase power to two phase power, a two phase motor electrically connected to said phase converter means, and control means electrically connected between said phase converter output and said two phase electric motor, said control means including gating means for controlling the part of each cycle of said two phase power applied to each winding of said two phase electric motor, speed sensing means for sensing the shaft speed of said two phase electric motor, and speed control menas responsive to said speed sensing means for controlling said gating means to maintain said shaft speed at a preselected value.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |