US3590334A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Static economizer circuit for power contactors
Assignee: Individual
•
Filing: 1969-10-24
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Granted: 1971-06-29
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Expires: 1989-10-24
Abstract
Abstract An economizer circuit that can close a power contactor with high current through a relay coil quickly and then go to a state of low holding current with low power dissipation is provided using transistor switching elements of which a first responds to a DC control voltage to turn on when a voltage signal of predetermined polarity and magnitude is applied and at least a second transistor responds to the output current of the first transistor to apply a feedback signal to drive the first transistor rapidly to full saturation. A capacitor charging by the output current of the first transistor controls the period of saturation of the second transistor holding the second transistor on until the capacitor is almost fully charged. During the brief saturation period a pulse of high current is developed through the relay coil to effect accelerated closure of the power contactor. After closure, when the transistors are not in saturation, an economical holding current is provided through the relay coil.
Inventors
- 👤 Donal Eugene Baker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:47
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/06; H01F7/08; H01F7/18; H01F7/1805
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
245 words
An economizer circuit, suitable for closing a power contactor and maintaining the contactor closed with low power dissipation, comprising: a pair of control terminals for receiving a DC control voltage; a first transistor connected with said pair of control terminals through at least one level setting impedance element to turn-on and develop an output current when a voltage signal of predetermined polarity and magnitude appears at said pair of control terminals; at least a second transistor connected to receive output current from said first transistor and to develop an amplified output current applied through a feedback impedance back to said first transistor for fast, complete saturation of said first transistor; a capacitor connected to be charged by the output current of said first transistor and discharged when control voltage on said pair of control terminals drops below a predetermined level; impedance means to control charging and discharging time constants of said capacitor so said at least a second transistor is held in a fully saturated condition for a first time period; an operating coil for a power contactor, said coil connected to said pair of control terminals for carrying a closing current of a first magnitude when said at least a second transistor is in saturation; a current limiting impedance in series with said coil between said pair of control terminals for limiting current therethrough to a second magnitude less than said first magnitude when said at least a second transistor is not in saturation.
Claim 2
Dependent Claim
245 words
An economizer circuit, suitable for closing a power contactor and maintaining the contactor closed with low power dissipation, comprising: a pair of control terminals for receiving a DC control voltage; a first transistor connected with said pair of control terminals through at least one level setting impedance element to turn-on and develop an output current when a voltage signal of predetermined polarity and magnitude appears at said pair of control terminals; at least a second transistor connected to receive output current from said first transistor and to develop an amplified output current applied through a feedback impedance back to said first transistor for fast, complete saturation of said first transistor; a capacitor connected to be charged by the output current of said first transistor and discharged when control voltage on said pair of control terminals drops below a predetermined level; impedance means to control charging and discharging time constants of said capacitor so said at least a second transistor is held in a fully saturated condition for a first time period; an operating coil for a power contactor, said coil connected to said pair of control terminals for carrying a closing current of a first magnitude when said at least a second transistor is in saturation; a current limiting impedance in series with said coil between said pair of control terminals for limiting current therethrough to a second magnitude less than said first magnitude when said at least a second transistor is not in saturation.
Claim 3
Dependent Claim
35 words
The subject matter of claim 1 further comprising: first and second diodes connected respectively from each side of said capacitor to one of said control terminals to provide a rapid discharge path for said capacitor.
Claim 4
Dependent Claim
52 words
The subject matter of claim 2 further comprising a third diode connected from one side of said capacitor to a circuit point adjacent said at least one level setting impedance element to limit voltage across said capacitor and reduce circuit sensitiVity to any ripple as may appear in said DC control voltage.
References Cited (Backward Citations)
US3116441A
Cited
US3341748A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |