US3812415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ferroresonant battery charger circuit
Assignee: C and D Power Systems Inc
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Filing: 1972-09-27
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Granted: 1974-05-21
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Expires: 1992-09-27
Abstract
Abstract A circuit for charging a storage battery is disclosed which uses a ferroresonant transformer in combination with a full-wave rectifier to supply direct current to charge the battery. The charging current is controlled by a single silicon controlled rectifier connected to substantially short circuit either all or a portion of one secondary winding of the transformer during increasing portions of half cycles of one polarity as the battery becomes charged. A voltage divider applies a preselected portion of the alternating current transformer output voltage, which is essentially the battery voltage, to gate the controlled rectifier. This preselected voltage is modified by the resistance varying characteristics of a thermistor which is responsive to heat produced by current through the controlled rectifier when it is conducting to reduce the current supplied to the battery. A lamp may be provided to visually indicate when the battery is charged.
Inventors
- 👤 Gilder B Van
- 👤 E Moyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:35
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/02; H02J7/04; H02J7/12; H02J7/90; H02J7/94; H02J7/947; H02J7/96; H02J2207/00; H02J2207/20; Y; Y10; Y10S; Y10S320/00; Y10S320/18; Y10S320/19; Y10S320/28
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
123 words
An improved circuit for charging a battery comprising, in combination, a ferroresonant transformer having an alternating current output, means for rectifying such alternating current output to obtain a direct current for charging a battery, a switch means including a controlled rectifier connected across said transformer output responsive to half-cycles of such alternating current output of one polarity, said half-cycles exceeding a predetermined voltage for triggering said controlled rectifier which substantially short circuits such alternating current output during the remainder of such half-cycles, means for modifying the level of voltage of said half-cycles including a thermistor, means responsive to an increasing average current through said controlled rectifier for heating said thermistor, and means decreasing the level of said voltage as said thermistor is heated.
Claim 2
Dependent Claim
123 words
An improved circuit for charging a battery comprising, in combination, a ferroresonant transformer having an alternating current output, means for rectifying such alternating current output to obtain a direct current for charging a battery, a switch means including a controlled rectifier connected across said transformer output responsive to half-cycles of such alternating current output of one polarity, said half-cycles exceeding a predetermined voltage for triggering said controlled rectifier which substantially short circuits such alternating current output during the remainder of such half-cycles, means for modifying the level of voltage of said half-cycles including a thermistor, means responsive to an increasing average current through said controlled rectifier for heating said thermistor, and means decreasing the level of said voltage as said thermistor is heated.
Claim 3
Dependent Claim
32 words
An improved battery charging circuit as set forth in claim 1, wherein the means for modifying the level of the voltage of said half-cycles includes a voltage divider cooperating with the thermistor.
Claim 4
Dependent Claim
65 words
An improved battery charging circuit, as set forth in claim 2, wherein said heating means includes an electric heater connected to heat said thermistor, and wherein said means connecting said controlled rectifier across said transformer output connects said heater in series with said controlled rectifier whereby an increased current flow through said controlled rectifier increases the temperature of said thermistor to decrease said predetermined voltage.
Claim 5
Dependent Claim
34 words
An improved battery charging circuit, as set forth in claim 3, and including an indicator lamp connected in parallel with said heater to visually indicate the level of the current through said controlled rectifier.
Claim 6
Dependent Claim
139 words
In combination with a high reactance alternating current power source, a full-wave rectifier to supply direct current to a load, a voltage divider shunting the power source and including a thermistor connected to vary the voltage at a tap in said voltage divider in response to temperature changes, a controlled rectifier, means connecting said controlled rectifier in shunt with the power source to substantially short said power source for the remainder of one half-cycle when gated to conductive condition, trigger means responsive to the tap voltage in said voltage divider to gate said controlled rectifier to conductive condition during such half-cycles when the tap exceeds a predetermined voltage, and means responsive to current flow in said controlled rectifier to vary the temperature of said thermistor to modify the voltage at said voltage divider tap applied to said trigger means.
Claim 7
Dependent Claim
139 words
In combination with a high reactance alternating current power source, a full-wave rectifier to supply direct current to a load, a voltage divider shunting the power source and including a thermistor connected to vary the voltage at a tap in said voltage divider in response to temperature changes, a controlled rectifier, means connecting said controlled rectifier in shunt with the power source to substantially short said power source for the remainder of one half-cycle when gated to conductive condition, trigger means responsive to the tap voltage in said voltage divider to gate said controlled rectifier to conductive condition during such half-cycles when the tap exceeds a predetermined voltage, and means responsive to current flow in said controlled rectifier to vary the temperature of said thermistor to modify the voltage at said voltage divider tap applied to said trigger means.
Claim 8
Dependent Claim
31 words
The device defined in claim 5 wherein said means responsive to current flow in said controlled rectifier includes an electric heater connected in the controlled rectifier circuit for heating said thermistor.
Claim 9
Dependent Claim
18 words
The device defined in claim 6 and including an indicating lamp connected in shunt with said heating coil.
Claim 10
Dependent Claim
26 words
The device defined in claim 5 wherein said alternating current power source includes a ferroresonant transformer with a power secondary windIng and a resonating secondary winding.
Claim 11
Dependent Claim
28 words
The device defined in claim 5 wherein said alternating current power source includes a ferroresonant transformer with a resonating secondary which also supplies the power to the load.
Claim 12
Dependent Claim
31 words
The device defined in claim 5 wherein said means responsive to current flow in said controlled rectifier includes means mounting said thermistor in a heat conducting relationship with said controlled rectifier.
Claim 13
Dependent Claim
18 words
The device defined in claim 9 wherein said mounting means includes an encapsulating body of heat conducting resin.
Claim 14
Dependent Claim
22 words
The device defined in claim 5 wherein said voltage divider includes a potentiometer for adjusting the voltage applied to said trigger means.
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) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |