US3818343A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic device for speed signalling in a d.c. motor
Assignee: Industrie Magneti Marelli SRL
•
Filing: 1972-04-24
•
Granted: 1974-06-18
•
Expires: 1992-04-24
Abstract
Abstract Apparatus for developing an alternating signal whose amplitude is proportional to motor speed for monitoring motors and the like, said apparatus comprising means for converting a signal from the motor supply proportional to the supply voltage to a continuous signal; second means for converting a signal from the motor proportional to the current drawn by the motor to an alternating signal; applying the aforesaid signals to respective input terminals of a logarithmic amplifier for developing a composite signal having a constant component and an alternating component; and filtering said composite signal to pass only said alternating signal whose amplitude is proportional to motor r.p.m. The resultant alternating signal may be converted to a d.c. or continuous signal by detector means for an output whose amplitude is proportional to motor r.p.m.
Inventors
- 👤 G Galli
- 👤 V Tateo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:14
CPC Classifications
B; B60; B60L; B60L3/00; B60L3/12; G; G01; G01P; G01P3/00; G01P3/42; G01P3/44; G01P3/46; Y; Y02; Y02T; Y02T10/00; Y02T10/60; Y02T10/64; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/909; Y10S388/922
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
172 words
An electronic device for continuously monitoring and determining the speed of a d.c. motor comprising: an alternating signal source of a first frequency coupled across the motor for supplying driving energy to the motor; first means for converting the output of said signal source into a signal (A) of a higher frequency and reduced amplitude relative to the output of said alternating signal source, said reduced amplitude being proportional to the amplitude of the output of said alternating signal source; second means coupled to said motor for converting the magnitude of current drawn by said motor into a d.c. signal (B) whose level is proportional to the magnitude of current drawn by said motor; third means having first and second inputs for receiving and generating the logarithmic value A/B derived from the outputs of said first and second means; means for filtering the output of said third means and for removing the d.c. component from the output of said third means to generate a signal whose amplitude is proportional to motor speed.
Claim 2
Dependent Claim
172 words
An electronic device for continuously monitoring and determining the speed of a d.c. motor comprising: an alternating signal source of a first frequency coupled across the motor for supplying driving energy to the motor; first means for converting the output of said signal source into a signal (A) of a higher frequency and reduced amplitude relative to the output of said alternating signal source, said reduced amplitude being proportional to the amplitude of the output of said alternating signal source; second means coupled to said motor for converting the magnitude of current drawn by said motor into a d.c. signal (B) whose level is proportional to the magnitude of current drawn by said motor; third means having first and second inputs for receiving and generating the logarithmic value A/B derived from the outputs of said first and second means; means for filtering the output of said third means and for removing the d.c. component from the output of said third means to generate a signal whose amplitude is proportional to motor speed.
Claim 3
Dependent Claim
35 words
The device of claim 1 wherein said third means comprises an electronic switch coupled to said alternating signal source and a transformer attenuator coupled between said electronic switch and one input of said third means.
Claim 4
Dependent Claim
33 words
The device of claim 1 wherein said second means comprises low-pass filter means coupled to said motor and amplifier means coupled between said low-pass filter and the second input of said third means.
Claim 5
Dependent Claim
15 words
The device of claim 1 wherein said d.c. motor is a series wound d.c. motor.
Claim 6
Dependent Claim
26 words
The device of claim 1 wherein said alternating signal source comprises a d.c. source and a Jones chopper coupled between said d.c. source and said motor.
Claim 7
Independent Claim
179 words
A method for measuring the rotational speed of a d.c. motor driven by a pulse generating source wherein use is made of two voltage signals, oNe of which is proportional to the current drained by the motor and the other of which is proportional to the motor supply voltage wherein measurement of the rotational speed of the d.c. motor comprises the steps of: converting the signal proportional to the current drawn by the motor to a d.c. bias signal (B) proportional to the average value of the current drawn by the motor; converting the output of the pulsating signal source into an alternating signal (A) having a constant frequency greater than the frequency of the pulsating signal source and having an amplitude proportional to its average value but smaller than the mangitude of said d.c. bias signal; logarithmically combining said d.c. bias signal B and said alternating signal A to develop a signal A/B; and removing the d.c. component from the developed signal to provide an alternating signal having an amplitude proportional to the rotational speed of the motor.
Claim 8
Independent Claim
179 words
A method for measuring the rotational speed of a d.c. motor driven by a pulse generating source wherein use is made of two voltage signals, oNe of which is proportional to the current drained by the motor and the other of which is proportional to the motor supply voltage wherein measurement of the rotational speed of the d.c. motor comprises the steps of: converting the signal proportional to the current drawn by the motor to a d.c. bias signal (B) proportional to the average value of the current drawn by the motor; converting the output of the pulsating signal source into an alternating signal (A) having a constant frequency greater than the frequency of the pulsating signal source and having an amplitude proportional to its average value but smaller than the mangitude of said d.c. bias signal; logarithmically combining said d.c. bias signal B and said alternating signal A to develop a signal A/B; and removing the d.c. component from the developed signal to provide an alternating signal having an amplitude proportional to the rotational speed of the motor.
Claim 9
Dependent Claim
33 words
The method of claim 6 further comprising the step of amplifying the alternating signal having an amplitude proportional to the rotational speed of the motor and detecting the peak amplitude of said signal.
Claim 10
Dependent Claim
101 words
The method of claim 6 wherein the step of converting the output of the pulsating signal source into a d.c. bias signal further comprises the steps of converting the output of the pulsating signal source into a d.c. signal proportional to its average value; converting the d.c. signal to a signal having a constant frequency which is higher than the frequency of the signal generated by the pulsating signal source and having an amplitude proportional to the average value of the signal generated by the pulsating signal source; removing the average value of said high frequency signal and reducing the amplitude.
Claim 11
Dependent Claim
33 words
The method of claim 6 wherein the step of generating a d.c. bias signal further comprises the steps of smoothing the current signal drawn by said motor and amplifying the smoothed current signal.
Claim 12
Dependent Claim
82 words
The method of claim 6 wherein the step of converting the output of the pulsating signal source further comprises the steps of smoothing said signal source to generate a d.c. signal proportional to the average value of the pulsating signal; converting the d.c. signal to a signal having a constant frequency greater than the frequency of the signal generated by the pulsating signal source and an amplitude proportional to the average value thereof; and reducing the amplitude of the higher frequency signal.
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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |