US3848168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed control system for a-c supplied universal motors
Assignee: Robert Bosch GmbH
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Filing: 1973-05-03
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Granted: 1974-11-12
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Expires: 1993-05-03
Abstract
Abstract A double polar thyristor, such as a Triac is connected in series with the universal motor. The Triac is triggered by two independently operating trigger circuits. One trigger circuit operates at a phase angle phi 1, between 70* to 110*, preferably about 90*. The second trigger circuit permits passage of current through a much larger phase angle phi 2, for example 180*. Load on the motor is sensed by sensing commutating pulses, and when the commutating pulses exceed predetermined values, the second trigger circuit is enabled. The motor, thus, under no-load conditions, will be triggered only by the first trigger circuit, the second trigger circuit becoming effective, for selected statistically distributed half wave pulses as the load on the motor increases, the statistical distribution, in time, of the trigger pulses from the second circuit (providing, preferably, full wave application of power to the motor) occurring in accordance with loading on the motor.
Inventors
- 👤 F Hornung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:36
CPC Classifications
H; H02; H02P; H02P25/00; H02P25/02; H02P25/10; H02P25/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
138 words
Speed control system for a-c supplied series wound commutator universal motors (M) comprising: controllable semiconductor switching means (Th) connectable for each half phase of the a-c supplied to the motor; means triggering said switching means (Th) selectively at a first fixed, preset phase angle ( phi 1) or at a second fixed, preset phase angle ( phi 2), wherein said second phase angle is greater than said first phase angle ( phi 2 > phi 1); and means connected to the motor and sensitive to motor loading, controlling said triggering means to trigger said semiconductor switching means, selectively, at said first preset phase angle ( phi 1) or said second preset phase angle ( phi 2), to provide trigger pulses to the controllable semiconductor switching means (Th), statistically distributed, in time, in accordance with loading on the motor.
Claim 2
Dependent Claim
138 words
Speed control system for a-c supplied series wound commutator universal motors (M) comprising: controllable semiconductor switching means (Th) connectable for each half phase of the a-c supplied to the motor; means triggering said switching means (Th) selectively at a first fixed, preset phase angle ( phi 1) or at a second fixed, preset phase angle ( phi 2), wherein said second phase angle is greater than said first phase angle ( phi 2 > phi 1); and means connected to the motor and sensitive to motor loading, controlling said triggering means to trigger said semiconductor switching means, selectively, at said first preset phase angle ( phi 1) or said second preset phase angle ( phi 2), to provide trigger pulses to the controllable semiconductor switching means (Th), statistically distributed, in time, in accordance with loading on the motor.
Claim 3
Dependent Claim
174 words
System according to claim 1, wherein said trigger means comprises a pair of parallel circuits, one circuit including a first phase angle sensitive means (D1, C1, R1), sensitive to said first phase angle ( phi 1) of the a-c supply and connected to trigger the controllable semiconductor switching means to connect the a-c supply to the motor at said first preset phase angle at each half-wave, to provide an average voltage thereto which determines the no-load speed thereof; and second phase angle sensitive means (D2, C2, R2, C3, R3) sensitive to the second preset phase angle ( phi 2) of the a-c supply and adapted to trigger the controllable semiconductor switching means to connect the a-c supply, at said second phase angle, the motor loading sensing means being connected to the motor to sense loading on the motor and connected to control said second phase angle sensitive means to be rendered effective to provide trigger pulses to the controllable semiconductor switching means (Th), statistically distributed, in time, in accordance with loading on the motor.
Claim 4
Dependent Claim
18 words
System according to claim 1, wherein the first phase angle ( phi 1) is between 70* to 110*.
Claim 5
Dependent Claim
13 words
System according to claim 3, wherein the first phase angle is about 90*.
Claim 6
Dependent Claim
16 words
System according to claim 1, wherein the second phase angle ( phi 2) is about 180*.
Claim 7
Dependent Claim
18 words
System according to claim 1, wherein the controllable semiconductor switching means comprises a bidirectional thyristor, or Triac (Th).
Claim 8
Dependent Claim
74 words
System according to claim 2, wherein the controllable semiconductor switching element comprises a bidirectional thyristor or Triac (Th), having its gate electrode connected to both said first and second phase angle sensitive means, each said phase angle sensitive means forming a control circuit for the gate electrode of said thyristor or Triac, and controlling conduction of the thyristor either during the lesser, or greater one of the phase angles ( phi 1, phi 2).
Claim 9
Dependent Claim
67 words
System according to claim 7, wherein the first phase angle sensitive means forming the first control circuit comprises a series circuit including a capacitor (C1) and a resistor (R1), connected across the a-c voltage supply; a trigger element (D1) having one electrode connected to the junction of said resistor and capacitor, and its other electrode to the gate electrode (G) of the bi-directional thyristor or Triac (Th).
Claim 10
Dependent Claim
20 words
System according to claim 8, wherein the resistor is adjustable, in order to adjust the no-load speed of the motor.
Claim 11
Dependent Claim
159 words
System according to claim 7, wherein the second phase angle sensitive means forming the second control circuit and sensitive to the second phase angle ( phi 2) is connected in parallel to the series circuit formed of the a-c supply source and the motor, and comprises a series circuit including: resistance means (R2, R3) and a capacitor (C2) to isolate the supply voltage from said control circuit; a parallel circuit comprising a resistor (R3) and a capacitor (C3) and connected in series with the series circuit formed of said resistance means and said first capacitor (C2); and a trigger element (D2) connected to sense the voltage across the resistor (R3) due to high-frequency commutating currents transferred to said resistor by the series circuit formed of the resistance means and the capacitor (C2), said trigger element transferring trigger pulses to the thyristor or Triac (Th) when the voltage across said resistor (R3) exceeds the triggering voltage of said trigger element.
Claim 12
Dependent Claim
16 words
System according to claim 9, wherein the trigger element is a Diac, or bi-directional diode (D1).
Claim 13
Dependent Claim
16 words
System according to claim 10, wherein the trigger element is a Diac or bi-directional diode (D2).
Claim 14
Dependent Claim
141 words
Universal motor and speed control system combination, adapted for connection to an a-c supply comprising: controllable switching means (Th) connected to apply each half-wave of tHe a-c supply to the motor; means deriving a sensing voltage from the commutating pulses arising at the motor; means controlling said semiconductor switching element to supply a-c power to said motor at a first phase angle at all times while the motor is connected to said source of supply; means supplying a-c power to said motor at a second phase angle which is greater than said first phase angle; and means enabling connection of said second phase angle supply means to said motor when commutating pulses in excess of a predetermined level are sensed whereby power, at said second and greater phase angle is applied to said motor upon increase in loading on the motor.
Claim 15
Dependent Claim
141 words
Universal motor and speed control system combination, adapted for connection to an a-c supply comprising: controllable switching means (Th) connected to apply each half-wave of tHe a-c supply to the motor; means deriving a sensing voltage from the commutating pulses arising at the motor; means controlling said semiconductor switching element to supply a-c power to said motor at a first phase angle at all times while the motor is connected to said source of supply; means supplying a-c power to said motor at a second phase angle which is greater than said first phase angle; and means enabling connection of said second phase angle supply means to said motor when commutating pulses in excess of a predetermined level are sensed whereby power, at said second and greater phase angle is applied to said motor upon increase in loading on the motor.
Claim 16
Dependent Claim
48 words
Combination according to claim 13, wherein the lower phase angle is set to be between 70* to 110*; and the higher phase angle is set to be about 180*, to supply full-wave power to the motor if the second phase angle controls application of power to the motor.
References Cited (Backward Citations)
US3588647A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |