US3708737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric motor speed sensing
Assignee: MIDWRSTERN INSTRUMENTS NC TULSA OK A CORP OF Co
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Filing: 1971-05-19
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Granted: 1973-01-02
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Expires: 1991-05-19
Abstract
Abstract Electrical motor speed sensing circuitry comprises: A. A CURRENT GENERATOR REMAINING ELECTRICALLY CONNECTED IN CURRENT SUPPLYING RELATION WITH THE MOTOR, THE GENERATOR HAVING A CONTROL INPUT, B. INPUT CONTROL MEANS TO ALTERNATE THE GENERATOR INPUT BETWEEN A FIRST SIGNAL LEVEL DURING FIRST TIME INTERVALS IN WHICH THE MOTOR IS ENGERGIZED BY THE GENERATOR TO DRIVE A LOAD, AND A SECOND SIGNAL LEVEL DURING SECOND TIME INTERVALS IN WHICH THE MOTOR COASTS, AND C. SENSING MEANS OPERABLE TO SAMPLE VALUES OF THE MOTOR BACK EMF during said second intervals. For servo operation, the input means may include a summing junction having a reference signal input and an input for a feed-back signal derived in response to operation of the sensing means.
Inventors
- 👤 H Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:23
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; H02P7/2913; G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/46; H02P5/00; H02P5/46; H02P5/50; H02P5/51; H02P7/288; H02P7/2885
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
114 words
Electrical motor speed sensing circuitry comprising a. a current generator remaining at all operating times electrically connected in current supplying relation with the motor, the generator having a control input, the generator comprising a linear amplifier that converts a voltage source input to a proportional current source output, b. input control means to alternate the generator input between a first signal level during first time intervals in which the motor is energized by the generator to drive a load, and a second signal level during second time intervals in which the motor coasts, and c. sensing means operable to sample and hold values of the motor full back EMF only during said second intervals.
Claim 2
Dependent Claim
114 words
Electrical motor speed sensing circuitry comprising a. a current generator remaining at all operating times electrically connected in current supplying relation with the motor, the generator having a control input, the generator comprising a linear amplifier that converts a voltage source input to a proportional current source output, b. input control means to alternate the generator input between a first signal level during first time intervals in which the motor is energized by the generator to drive a load, and a second signal level during second time intervals in which the motor coasts, and c. sensing means operable to sample and hold values of the motor full back EMF only during said second intervals.
Claim 3
Dependent Claim
8 words
The circuitry of claim 1 including the motor.
Claim 4
Dependent Claim
46 words
The circuitry of claim 1 wherein said input control means includes input switch mechanism operable to alternate the generator input between said first and second levels, and a shaping network connected between the switch mechanism and the generator to minimize transient voltages generated at the motor.
Claim 5
Dependent Claim
34 words
The circuitry of claim 3 wherein said input means includes a summing junction having a reference signal input and an input foR a feed-back signal derived in response to operation of said sensing means.
Claim 6
Dependent Claim
51 words
The circuitry of claim 4 wherein said input means includes a device responsive to the output of said summing junction to supply said first signal level to said switch mechanism and an attenuator network responsive to the output of said device to supply said second signal level to said switch mechanism.
Claim 7
Dependent Claim
38 words
The circuitry of claim 1 wherein said sensing means includes a sample and hold circuit having an input, and sample and hold switch mechanism electrically connected between the motor and the input of the sample and hold circuit.
Claim 8
Dependent Claim
30 words
The circuitry of claim 6 wherein said input means includes a summing junction having a reference signal input, and another input electrically connected with the sample and hold circuit output.
Claim 9
Dependent Claim
21 words
The circuitry of claim 7 including circuitry to synchronously control said input switch mechanism and said sample and hold switch mechanism.
Claim 10
Dependent Claim
29 words
The circuitry of claim 1 including said motor, and a load in the form of a stored informational media drive element operatively connected in driven relation with the motor.
Claim 11
Dependent Claim
16 words
The circuitry of claim 9 wherein said media drive element comprises a magnetic tape drive capstan.
Claim 12
Dependent Claim
37 words
The circuitry of claim 9 including a pair of magnetic tape rolls between which tape is transported in response to rotation of said drive element, and a magnetic head past which the transported tape is adjacently movable.
Claim 13
Dependent Claim
26 words
The circuitry as defined in claim 1 including multiple electrical motors and switch means to selectively connect the generator in current supplying relation with said motors.
Claim 14
Dependent Claim
26 words
The circuitry of claim 12 including multiple loads in the form of stored informational media drive elements respectively operatively connected in driven relation with said motors.
Claim 15
Dependent Claim
15 words
The circuitry of claim 1 wherein said generator includes means to supply bipolar output current.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |