Patent US3617847A successfully refreshed from Google Patents.
US3617847A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Speed regulating electronic circuit for dc motor control
Assignee: Eastman Kodak Co
•
Filing: 1970-02-24
•
Granted: 1971-11-02
•
Expires: 1990-02-24
Abstract
Abstract This invention relates to a speed regulating electronic circuit for a DC motor. A tachometer generator, driven by the armature shaft of the DC motor, provides a voltage signal which is a function of the instantaneous speed of the motor. The tachometer generator output voltage is combined with a reference voltage which is a function of the desired speed, and the difference is applied to a plurality of amplifiers in cascade to develop a DC potential level which is applied across n equal resistors connected in series to provide n voltage drops, where n is an integer selected from the series 2,3,4,........n. These n voltage drops are applied to a first set of n transistor amplifiers connected in cascode, and the n outputs which they provide are applied to a second set of n transistors connected in cascode and in series with the motor armature. This arrangement insures that each transistor of the second set of n transistors will dissipate equal power, regardless of armature load current demand, with concomitant advantages in increased efficiency and lower costs.
Inventors
- 👤 Frederick W Powell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:31
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/288; H02P7/2885; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/909
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
371 words
A circuit adapted to regulate the rotational velocity of an output shaft of a DC motor having an armature winding, said circuit comprising: a. a power supply for producing an AC output signal; b. a signal converter network connected to said power supply for converting the AC signal produced by said supply into a DC signal; c. variable circuit means for producing a reference signal having a predetermined value from said DC signal, said circuit means including means for regulating the magnitude of said reference signal to correspond to the desired rotational velocity of the output shaft; d. a transducer for generating a DC signal related to the rotational velocity of the shaft; e. means for comparing said reference signal generated by said variably circuit means to said DC signal generated by said transducer wherein a DC control signal having a magnitude equal to the difference between said reference signal and said DC signal is generated; f. a DC voltage-amplifying transistor network comprising an input transistor stage responsive to said DC control signal and an output transistor stage for producing a DC signal related to said DC control signal; g. n resistors of equal ohmic magnitude connected in series with said output transistor stage whereby n equal voltages are dropped across said n resistors whose magnitudes are related to said DC signal generated at the output of said transistor network, n being an integer selected from the series 2, 3, 4, ..., n; h. a first set of n transistor amplifiers connected in cascode and adapted to receive said n equal voltages as n inputs and to produce n voltage outputs respectively; and i. a second set of n transistor amplifiers connected in cascode and adapted to received as inputs said n voltage outputs from said first set of n transistor amplifiers and to produce n voltage outputs respectively, said second set of n transistors being connected in series with the armature winding so that each of said n transistor amplifiers in said second set can be utilized to its maximum power dissipation rating and whereby the power dissipated in each of said n transistors in said second set is substantially equal regardless of the load current through the armature winding.
Claim 2
Dependent Claim
371 words
A circuit adapted to regulate the rotational velocity of an output shaft of a DC motor having an armature winding, said circuit comprising: a. a power supply for producing an AC output signal; b. a signal converter network connected to said power supply for converting the AC signal produced by said supply into a DC signal; c. variable circuit means for producing a reference signal having a predetermined value from said DC signal, said circuit means including means for regulating the magnitude of said reference signal to correspond to the desired rotational velocity of the output shaft; d. a transducer for generating a DC signal related to the rotational velocity of the shaft; e. means for comparing said reference signal generated by said variably circuit means to said DC signal generated by said transducer wherein a DC control signal having a magnitude equal to the difference between said reference signal and said DC signal is generated; f. a DC voltage-amplifying transistor network comprising an input transistor stage responsive to said DC control signal and an output transistor stage for producing a DC signal related to said DC control signal; g. n resistors of equal ohmic magnitude connected in series with said output transistor stage whereby n equal voltages are dropped across said n resistors whose magnitudes are related to said DC signal generated at the output of said transistor network, n being an integer selected from the series 2, 3, 4, ..., n; h. a first set of n transistor amplifiers connected in cascode and adapted to receive said n equal voltages as n inputs and to produce n voltage outputs respectively; and i. a second set of n transistor amplifiers connected in cascode and adapted to received as inputs said n voltage outputs from said first set of n transistor amplifiers and to produce n voltage outputs respectively, said second set of n transistors being connected in series with the armature winding so that each of said n transistor amplifiers in said second set can be utilized to its maximum power dissipation rating and whereby the power dissipated in each of said n transistors in said second set is substantially equal regardless of the load current through the armature winding.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |