US3683253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
C.e.m.f. motor speed control system
Assignee: Western Reserve Electronics Inc
•
Filing: 1970-09-16
•
Granted: 1972-08-08
•
Expires: 1990-09-16
Abstract
Abstract A D.C. motor is connected to a current supply through a switch, the ''''on'''' time of which determines the motor speed. Exact speed control is effected by sampling the C.E.M.F. during the ''''off'''' time of the power switch, after the inductive jump has decayed, before the motor speed has decayed and before the next power ''''on'''' application occurs. The C.E.M.F. is compared with a reference voltage and the motor turned ''''on'''' or left ''''off'''' depending on whether the C.E.M.F. is higher or lower than the reference voltage. The reference voltage may be manually or automatically adjusted to determine ultimate motor speed.
Inventors
- 👤 Edward W Rummel
- 👤 Richard H Funk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:55
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; H02P7/2913; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/901; Y10S388/907; Y10S388/921
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
244 words
An apparatus for controlling the speed of a D.C. motor which includes a source of power for the motor, power switch means between the source of power and the motor to turn the motor on and off, a control means for controlling said power switch means including a C.E.M.F. sensing switch and means connected by the sensing switch to the motor when the power is off to receive the C.E.M.F. of the motor, a source of variable voltage and means for comparing the C.E.M.F. with the variable voltage source to provide a sensed difference voltage and for causing said power switch to close if the C.E.M.F. falls below the value set by the variable voltage source, delay means for the sensing switch to hold the sensing switch open until the decay of the inductive voltage jump due to opening the power switch, generator means for generating an alternating voltage of a predetermined value and the voltage difference between the C.E.M.F. and the variable control voltage is compared in said comparing means with said alternating voltage to cause said power switch to operate, said alternating voltage being of sawtooth waveform and the rising voltage of said sawtooth wave is used to control the turn on of the power switch and said sensed difference voltage is used to control the time the sawtooth turns on the switch and the flyback of said sawtooth waveform is used to control the turn on of the C.E.M.F. sensing switch.
Claim 2
Independent Claim
244 words
An apparatus for controlling the speed of a D.C. motor which includes a source of power for the motor, power switch means between the source of power and the motor to turn the motor on and off, a control means for controlling said power switch means including a C.E.M.F. sensing switch and means connected by the sensing switch to the motor when the power is off to receive the C.E.M.F. of the motor, a source of variable voltage and means for comparing the C.E.M.F. with the variable voltage source to provide a sensed difference voltage and for causing said power switch to close if the C.E.M.F. falls below the value set by the variable voltage source, delay means for the sensing switch to hold the sensing switch open until the decay of the inductive voltage jump due to opening the power switch, generator means for generating an alternating voltage of a predetermined value and the voltage difference between the C.E.M.F. and the variable control voltage is compared in said comparing means with said alternating voltage to cause said power switch to operate, said alternating voltage being of sawtooth waveform and the rising voltage of said sawtooth wave is used to control the turn on of the power switch and said sensed difference voltage is used to control the time the sawtooth turns on the switch and the flyback of said sawtooth waveform is used to control the turn on of the C.E.M.F. sensing switch.
Claim 3
Dependent Claim
69 words
An apparatus as described in claim 1, wherein power turn on delay means is connected between the comparing means and the power switch and said means for comparing is an error amplifier with an input connected to said C.E.M.F. sensing means and said source of variable voltage to amplify the difference between the two and having an output connected to said last mentioned delay means through said comparing 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) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |