US3764871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Starting circuit for induction motor
Assignee: Design and Manufacturing Corp
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Filing: 1971-05-27
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Granted: 1973-10-09
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Expires: 1991-05-27
Abstract
Abstract A circuit for the automatic starting of an induction motor of the type having a main or running winding and at least one phase or starting winding. The starting circuit comprises a current sensing means which is series connected with the main or running winding to a source of electrical power. Said sensing means is also series connected to the combination of a memory circuit and a threshold detection means. The high current drawn by the main or running winding, when initially energized, is sensed by the current sensing means and, when sufficiently high, a signal is passed to an interfacing device between a power source and the starting winding by the memory circuit and the detection means calibrated to pass the signal at voltages in excess of that voltage of the signal which exists when the motor is running at normal speed. This signal is present at the gate of the interfacing device during the entire time that the phase or starting winding is to be energized. The interfacing device, in turn, connects the phase or starting winding of the motor to the power source. When the motor approaches normal running speed and the initial high current drawn by the main or running winding diminishes, the phase or starting winding of the motor will be disconnected from the power source through the action of the calibrated detection means, the memory circuit and deenergization of the gate of the interfacing device.
Inventors
- 👤 P Scheuer
- 👤 V Zane
- 👤 S Sample
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:09
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/42; H02P1/44; D; D06; D06F; D06F34/00; D06F34/08; D06F2103/00; D06F2103/44; D06F2103/46; D06F2105/00; D06F2105/46; D06F37/00; D06F37/30; D06F37/304
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
536 words
A circuit for the automatic starting of an induction motor of the type having a main running winding, a first starting winding and a second starting winding to cause said motor to run in a direction opposite to that initiated by said first starting winding, said circuit comprising a source of electrical energy and first and second leads therefrom, a third lead containing in series said main running winding and means for sensing the current drawn by said main running winding and producing an electric signal proportional thereto, a fourth lead containing in series said first starting winding and a first bi-directional semi-conductor switch, a fifth lead, said fifth lead containing in series said second starting winding and a second bidirectional semi-conductor switch, means to connect and disconnect said third, fourth and fifth leads across said first and second leads, means for conducting said sensing means signal to a start and stop threshold detecting means calibrated to pass a start signal at voltages in excess of that voltage sensing means signal which exists when said motor is running at normal speed, an integrated logic circuit having first, second and third outputs, said means for connecting and disconnecting said third lead across said first and second leads comprising a third bidirectional semi-conductor switch connected in series with said main running winding and said sensing means in said third lead, said first output of said integrated logic circuit being connected to the gate of said third bi-directional semi-conductor switch, said means for connecting aNd disconnecting said fourth and fifth leads across said first and second leads comprising a first switching transistor and a second switching transistor, said threshold detecting means being connected to the collectors of said first and second switching transistors, the emitters of said first and second transistors being connected to the gates of said first and second bi-directional semi-conductor switches respectively, said second and third outputs of said integrated logic circuit being connected to the bases of said first and second switching transistors respectively, whereby when said first and second logic circuit outputs provide a logical 1 at the gate of said third bi-directional semi-conductor switch and the base of said first switching transistor respectively, and said third output provides a logical zero at the base of said second switching transistor, said third and fourth leads are connected across said first and second leads and said fifth lead is disconnected therefrom, said main winding will be energized, said second starting winding will be deenergized and said first starting winding will be energized for so long as said threshold detecting means transmits said start signal, and when said first and third logic circuit outputs provide a logical 1 at the gate of said third bi-directional semi-conductor switch and the base of said second switching transistor respectively, and said second output provides a logical zero at the base of said first switching transistor, said third and fifth leads are connected across said first and second leads and said fourth lead is disconnected therefrom, said main running winding will be energized, said first starting winding will be deenergized and said second starting winding will be energized for so long as said threshold detecting means transmits said start signal.
Claim 2
Dependent Claim
536 words
A circuit for the automatic starting of an induction motor of the type having a main running winding, a first starting winding and a second starting winding to cause said motor to run in a direction opposite to that initiated by said first starting winding, said circuit comprising a source of electrical energy and first and second leads therefrom, a third lead containing in series said main running winding and means for sensing the current drawn by said main running winding and producing an electric signal proportional thereto, a fourth lead containing in series said first starting winding and a first bi-directional semi-conductor switch, a fifth lead, said fifth lead containing in series said second starting winding and a second bidirectional semi-conductor switch, means to connect and disconnect said third, fourth and fifth leads across said first and second leads, means for conducting said sensing means signal to a start and stop threshold detecting means calibrated to pass a start signal at voltages in excess of that voltage sensing means signal which exists when said motor is running at normal speed, an integrated logic circuit having first, second and third outputs, said means for connecting and disconnecting said third lead across said first and second leads comprising a third bidirectional semi-conductor switch connected in series with said main running winding and said sensing means in said third lead, said first output of said integrated logic circuit being connected to the gate of said third bi-directional semi-conductor switch, said means for connecting aNd disconnecting said fourth and fifth leads across said first and second leads comprising a first switching transistor and a second switching transistor, said threshold detecting means being connected to the collectors of said first and second switching transistors, the emitters of said first and second transistors being connected to the gates of said first and second bi-directional semi-conductor switches respectively, said second and third outputs of said integrated logic circuit being connected to the bases of said first and second switching transistors respectively, whereby when said first and second logic circuit outputs provide a logical 1 at the gate of said third bi-directional semi-conductor switch and the base of said first switching transistor respectively, and said third output provides a logical zero at the base of said second switching transistor, said third and fourth leads are connected across said first and second leads and said fifth lead is disconnected therefrom, said main winding will be energized, said second starting winding will be deenergized and said first starting winding will be energized for so long as said threshold detecting means transmits said start signal, and when said first and third logic circuit outputs provide a logical 1 at the gate of said third bi-directional semi-conductor switch and the base of said second switching transistor respectively, and said second output provides a logical zero at the base of said first switching transistor, said third and fifth leads are connected across said first and second leads and said fourth lead is disconnected therefrom, said main running winding will be energized, said first starting winding will be deenergized and said second starting winding will be energized for so long as said threshold detecting means transmits said start signal.
Claim 3
Dependent Claim
46 words
The structure claimed in claim 1 wherein said current sensing means comprises a transformer, said trnasformer having a primary portion in series with said main motor winding in said third lead, said transformer having a secondary portion, said proportional signal being induced in said secondary portion.
Claim 4
Dependent Claim
33 words
The structure claimed in claim 1 wherein said means for sensing the current drawn by said main running winding comprises a resistor in series with said main running winding in said third lead.
Claim 5
Dependent Claim
62 words
The structure claimed in claim 1 wherein said means for conducting said sensing means signal to said threshold detecting device is a memory circuit comprising a diode-capacitor half-wave rectifier in series with a resistor being so connected between said second and third leads that the DC voltage appearing across said capacitor is proportional to the current flowing in said main running winding.
Claim 6
Dependent Claim
17 words
The structure claimed in claim 1 wherein said threshold detecting means is a single level detecting means.
Claim 7
Dependent Claim
53 words
The structure claimed in claim 1 wherein said threshold detecting means is a bi-level detecting means calibrated to initiate said start signal at a first sensed voltage level and to terminate said start signal at a second sensed voltage level, said first sensed voltage level being higher than said second sensed voltage lead.
Claim 8
Dependent Claim
79 words
The structure claimed in claim 1 including a third switching transistor between said threshold detecting means and said first and second switching transistors, said threshold detecting means being connected through a first resistor to the base of said third switching transistor, the collector of said third switching transistor being connected through a second resistor to a source of DC power, the emittor of said third switching transistor being connected to the collectors of said first and second switching transistors.
Claim 9
Dependent Claim
29 words
The structure claimed in claim 4 wherein said memory circuit has an output connected to said threshold detecting means, said threshold detecting means being a single level detecting means.
Claim 10
Dependent Claim
65 words
The structure claimed in claim 4 wherein said memory circuit has an output connected to said tHreshold detecting means, said threshold detecting means being a bi-level detecting means calibrated to initiate said start signal at a first sensed voltage level and to terminate said start signal at a second sensed voltage level, said first sensed voltage level being higher than said second sensed voltage level.
Claim 11
Dependent Claim
15 words
The structure claimed in claim 5 wherein said threshold detecting means comprises a zener diode.
Claim 12
Dependent Claim
14 words
The structure claimed in claim 5 wherein said threshold detecting means comprises a resistor.
Claim 13
Dependent Claim
25 words
The structure claimed in claim 6 wherein said bi-level detecting means comprises a Schmitt trigger and a source of DC current for said Schmitt trigger.
Claim 14
Dependent Claim
55 words
The structure claimed in claim 6 wherein said threshold detecting means has an input to receive the output of said sensing means, a memory circuit in said connection between said detecting means and said collectors of said first and second switching transistors, said memory circuit comprising a diode-capacitor half-wave rectifier in series with a resistor.
Claim 15
Dependent Claim
25 words
The structure claimed in claim 9 wherein said bi-level detecting means comprises a Schmitt trigger and a source of DC current for said Schmitt trigger.
Claim 16
Dependent Claim
79 words
The structure claimed in claim 9 including a third switching transistor between said threshold detecting means and said first and second switching transistors, said threshold detecting means being connected through a first resistor to the base of said third switching transistor, the collector of said third switching transistor being connected through a second resistor to a source of DC power, the emittor of said third switching transistor being connected to the collectors of said first and second switching transistors.
Claim 17
Dependent Claim
55 words
The structure claimed in claim 9 wherein said logic circuit incorporates said first and second switching transistors, said second and third outputs of said logic circuit being connected directly to said gates of said first and second bi-directional semi-conductor switches, said logic circuit having an input for said start signal from said threshold detecting means.
Claim 18
Dependent Claim
53 words
The structure claimed in claim 9 wherein said logic circuit incorporates said first and second switching transistors, said second and third outputs of said logic circuit being connected directly to said gates of said first and second bi-directional semi-conductor switches, said logic circuit incorporating a part at least of said threshold detecting means.
Claim 19
Dependent Claim
63 words
The structure claimed in claim 9 wherein said logic circuit incorporates said first and second switching transistors, said second and third outputs of said logic circuit being connected directly to said gates of said first and second bi-directional semi-conductor switches, said logic circuit incorporating said memory circuit and said threshold detecting means and having an input for a signal from said sensing means.
Claim 20
Dependent Claim
60 words
The structure claimed in claim 13 wherein said logic circuit incorporates said first and second switching transistors, said second and third outputs of said logic circuit being connected directly to said gates of said first and second bi-directional semi-conductor switches, said logic circuit incorporating said memory circuit and having an input for said start signal from said threshold detecting means.
Claim 21
Dependent Claim
63 words
The structure claimed in claim 13 wherein said logic circuit incorporates said first and second switching transistors, said second and third outputs of said logic circuit being connected directly to said gates of said first and second bi-directional semi-conductor switches, said logic circuit incorporating said memory circuit and said threshold detecting means and having an input for a signal from said sensing means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-08 | 1977-04-09 | 1977-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-08 | 1981-04-09 | 1981-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-08 | 1985-04-09 | 1985-10-09 | $7700.00 | Window Closed / Lapsed |