Patent US3790874A successfully refreshed from Google Patents.
US3790874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor drive control system
Assignee: Cleveland Machine Controls Inc
•
Filing: 1972-07-27
•
Granted: 1974-02-05
•
Expires: 1992-07-27
Abstract
Abstract A motor drive control system for driving an electrical motor such that the motor speed is dependent upon an error signal representative of the difference between a desired or reference speed, and a speed signal provided by a DC tachometer generator. The tachometer generator is located in a feedback loop for providing a DC signal having a magnitude that varies with motor speed. A monitoring circuit serves to monitor electrical characteristics of the tachometer generator for purposes of preventing energization of the motor in the event of an unwanted electrical characteristic taking place in the tachometer generator feedback loop. The unwanted characteristic may be an improper connection of the tachometer generator in the feedback loop or a faulty tachometer generator, such as shorted armature windings or an open circuit condition between the tachometer brushes.
Inventors
- 👤 R Klimo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 06:19
CPC Classifications
G; G01; G01P; G01P1/00; G01P1/07; G01P1/08; G01P1/10; G01P1/103; H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
182 words
A motor drive control system for controlling the motor speed of an electrical motor, comprising circuit means including switch means for supplying energy to a said motor through said switch means from a power source, means for varying said motor speed by varying the supply of energy to said motor means in dependence upon a control signal, DC tachometer generater means having a pair of output terminals providing a DC signal therebetween representative of the motor speed, means for providing a said control signal dependent upon a given relationship between said DC signal and a reference level, and monitor circuit means connected to said tachometer generator means for actuating said switch means to prevent said supply of energy to said motor when a given electrical condition exists between said tachometer generator output terminals, said tachometer generator means having a normally completed series circuit extending between said output terminals, said monitoring circuit means including means for applying a test current so as to flow through said series circuit and circuit malfunction detecting means for detecting a circuit malfunction existing between said output terminals.
Claim 2
Dependent Claim
182 words
A motor drive control system for controlling the motor speed of an electrical motor, comprising circuit means including switch means for supplying energy to a said motor through said switch means from a power source, means for varying said motor speed by varying the supply of energy to said motor means in dependence upon a control signal, DC tachometer generater means having a pair of output terminals providing a DC signal therebetween representative of the motor speed, means for providing a said control signal dependent upon a given relationship between said DC signal and a reference level, and monitor circuit means connected to said tachometer generator means for actuating said switch means to prevent said supply of energy to said motor when a given electrical condition exists between said tachometer generator output terminals, said tachometer generator means having a normally completed series circuit extending between said output terminals, said monitoring circuit means including means for applying a test current so as to flow through said series circuit and circuit malfunction detecting means for detecting a circuit malfunction existing between said output terminals.
Claim 3
Dependent Claim
55 words
A motor drive control system as set forth in claim 1 wherein said series circuit includes at least an armature winding, a pair of commutator bars connected to said armature winding and a pair of armature brushes respectively connected to said output terminals and positioned so as to make electrical contact with said commutator bars.
Claim 4
Dependent Claim
56 words
A motor drive control system as set forth in claim 1 wherein said test current applying means includes circuit means for applying an AC current signal as said test current to said series circuit and said detector circuit means includes AC voltage detector means for detecting whether an AC voltage is present across said output terminals.
Claim 5
Dependent Claim
47 words
A motor drive control system as set forth in claim 3 wherein said AC signal applying means includes oscillator means for developing an AC signal and meanS coupling said oscillator means to said series circuit such that an alternating test current is applied to said series circuit.
Claim 6
Dependent Claim
39 words
A motor drive control system as set forth in claim 4 wherein said coupling means includes a current transformer having its primary winding connected to said oscillator means and its secondary winding connected in series with said series circuit.
Claim 7
Dependent Claim
47 words
A motor drive control system as set forth in claim 5 including filter means tuned to the frequency of said oscillator means for completing the circuit for said current transformer secondary winding across said tachometer generator output terminals so that current may flow through the completed circuit.
Claim 8
Dependent Claim
52 words
A motor drive control system as set forth in claim 3 wherein said AC voltage detector means includes transformer means connected across said tachometer output terminals and rectifying means connected to said transformer means for developing a DC output signal so long as an AC signal is present across said output terminals.
Claim 9
Dependent Claim
51 words
A motor drive control system as set forth in claim 7 including means for actuating said switching means to an open condition in response to the absence of said DC output signal from said voltage detecting means to thereby prevent the supply of energy from said power source to said motor.
Claim 10
Dependent Claim
75 words
A motor drive control system as set forth in claim 7 wherein said monitoring circuit means includes circuit continuity means for providing a second DC output signal so long as electrical continuity is maintained between said tachometer output terminals, and switch control circuit means for maintaining said switching means in a closed condition to supply power to said DC motor only so long as both said first and said second output signals are concurrently present.
Claim 11
Dependent Claim
45 words
A motor drive control system as set forth in claim 1 wherein said circuit malfunction detecting means includes continuity determining means for determining whether electrical continuity is maintained between said tachometer generator output terminals in dependence upon whether said test current flows between said terminals.
Claim 12
Dependent Claim
71 words
A motor drive control system as set forth in claim 10 wherein said circuit continuity means includes output circuit means for developing a DC output signal so long as circuit continuity is maintained between said tachometer generator output terminals, and control circuit means for actuating said switching means to an open condition to prevent supply of energy to said motor means in response to the absence of a said output signal.
Claim 13
Dependent Claim
64 words
A motor drive control system as set forth in claim 11 wherein said means for applying a test current to said series circuit includes means for providing an AC signal of a given requency as said test current and said malfunction detecting means includes means for providing a DC output signal so long as said AC test signal current flows through said series circuit.
Claim 14
Dependent Claim
49 words
A motor drive control system as set forth in claim 12 wherein said malfunction detecting means includes means for comparing said DC output signal with a reference signal to provide a DC output potential of a given polarity so long as said test current flows through said series circuit.
Claim 15
Dependent Claim
46 words
A motor drive control system as set forth in claim 13 wherein said malfunction detecting means includes circuit means for developing a second DC output potential only so long as an AC voltage is developed across said tachometer output terminals indicative of inductance being present therebetween.
Claim 16
Dependent Claim
51 words
A motor drive control system as set forth in claim 14 including AND circuit means for maintaining said switching means in a closed condition to energize said motor means only so long as both a said first output potential of said given polarity and said second output potential are concurrently provided.
Claim 17
Dependent Claim
118 words
Apparatus for testing an electrodynamic machine having a series circuit including at least one winding interposed between a pair of terminals comprising circuit meaNs interconnecting said terminals to complete an electrical circuit thereacross, and including means for applying an AC test signal to flow through said series circuit, AC voltage detecting means for providing a first output signal so long as an AC voltage is developed across said terminals in response to said test signal, current detecting means for providing a second output signal so long as said test current flows through said electrical circuit, and output indicating means for providing an output indication only so long as both said first and second output signals are concurrently present.
Claim 18
Dependent Claim
118 words
Apparatus for testing an electrodynamic machine having a series circuit including at least one winding interposed between a pair of terminals comprising circuit meaNs interconnecting said terminals to complete an electrical circuit thereacross, and including means for applying an AC test signal to flow through said series circuit, AC voltage detecting means for providing a first output signal so long as an AC voltage is developed across said terminals in response to said test signal, current detecting means for providing a second output signal so long as said test current flows through said electrical circuit, and output indicating means for providing an output indication only so long as both said first and second output signals are concurrently present.
Claim 19
Dependent Claim
45 words
Apparatus as set forth in claim 16 wherein said AC test signal applying means includes oscillator means for providing an AC signal and means coupling said oscillator means with said electrical circuit such that said AC test signal is caused to flow through said circuit.
Claim 20
Dependent Claim
39 words
Apparatus as set forth in claim 17 wherein said AC voltage detecting means includes transformer means connected across said terminals for developing a said AC voltage and rectifying means for providing a DC signal as said first output signal.
Claim 21
Dependent Claim
30 words
Apparatus as set forth in claim 17 including AND circuit means for energizing said output indicating means only so long as said first and second output signals are concurrently present.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |