Means and methods for ferro-resonant float charging circuits

Claim 2

A float charging device comprising a ferro-resonant transformer including a primary winding for supplying power and a first and second secondary winding, charging means operatively connected to said first winding for supplying charging power to a battery from said transformer, control means operatively connected to said second winding and including a capacitor and a switching means, and a triac in series with the secondary winding and also including a switching means, said switching means being operatively connected to the charging means and being responsive to the terminal voltage of the battery being charged, said switching means being adapted for automatically cutting off current flow in the second secondary winding when the battery terminal voltage attains a preselected magnitude, and for permitting current to flow through said second secondary winding at all other times.

Claim 3

The device of claim 1 in which the control means includes a capacitor and a triac in series with the second secondary winding.

Claim 4

The device of claim 1 in which the control means includes a capacitor and a triac in series with the second secondary winding and the switching means includes a first electronic switch which goes into conduction when the battery attains the preselected terminal voltage, and which conduction biases the triac into a state of non-conduction causing the secondary winding circuit to open and removing the capacitive load from the transformer.

Claim 5

The device of claim 1 in which the switching means also includes a second electronic switch which resets the first electronic switch each half cycle whereby to provide continuous monitoring of the battery terminal voltage.

Claim 6

A float charging device comprising a ferro-resonant transformer including a primary winding and first and second secondary windings, the first secondary winding being provided with a centertap, a positive bus and a negative bus, first and second rectifying diodes connected at their anodes respectively to opposing legs of the first secondary winding and at their cathodes to the positive bus, said centertap being connected to said negative bus, a voltage reference circuit including a Zener and a first resistor connected between the positive and negative bus, a voltage divider circuit operatively connected between the positive and negative bus and including a variable resistor and the gate to ground resistance of a triac, a triggering circuit operatively connected between one leg of the first secondary winding and the negative bus and including a voltage monitoring point, first switching means provided with a first lead connected to the Zener anode and a second lead connected to the negative bus and also being provided with a third lead connected to the voltage divider circuit, said first switching means for initiating conduction therein when the voltage differentials between the voltage at the three leads thereof indicates that the battery terminal voltage has attained a predetermined magnitude, second switching means including a first lead connected to the voltage divider circuit and a second lead connected to the negative bus and also including a third lead to the triggering circuit at the voltage monitoring point, said second switching means for going into conduction during every positive half cycle of voltage across the first secondary winding whereby to reduce the voltage presented to the third lead of the first switching means from the voltage divider circuit when the second switching means is in conduction, and a capacitor connected in series with the line leads of the triac and the second secondary winding, the voltage at the gate of the triac being such that the triac wilL be normally in conduction and will remain in conduction until the first switching means goes into conduction at which time the current drawn through the voltage divider circuit will cause the voltage at the triac gate to be biased below cutoff, said first and second secondary windings being so constructed and adapted that the second secondary winding will supply a resonant capacitive load to the transformer when the triac is in conduction, and the first secondary winding will supply battery charging power to the battery so long as the secondary windings are in resonant conduction.

Claim 7

A float charging device comprising a ferro-resonant transformer including a primary winding and first and second secondary windings, the first secondary winding being provided with a centertap, a positive bus and a negative bus, first and second rectifying diodes connected at their anodes respectively to opposing legs of the first secondary winding and at their cathodes to the positive bus, said centertap being connected to said negative bus, a voltage reference circuit including a Zener and a first resistor connected between the positive and negative bus, a voltage divider circuit operatively connected between the positive and negative bus and including a variable resistor and the gate to ground resistance of a triac, a triggering circuit operatively connected between one leg of the first secondary winding and the negative bus and including a voltage monitoring point, first switching means provided with a first lead connected to the Zener anode and a second lead connected to the negative bus and also being provided with a third lead connected to the voltage divider circuit, said first switching means for initiating conduction therein when the voltage differentials between the voltage at the three leads thereof indicates that the battery terminal voltage has attained a predetermined magnitude, second switching means including a first lead connected to the voltage divider circuit and a second lead connected to the negative bus and also including a third lead to the triggering circuit at the voltage monitoring point, said second switching means for going into conduction during every positive half cycle of voltage across the first secondary winding whereby to reduce the voltage presented to the third lead of the first switching means from the voltage divider circuit when the second switching means is in conduction, and a capacitor connected in series with the line leads of the triac and the second secondary winding, the voltage at the gate of the triac being such that the triac wilL be normally in conduction and will remain in conduction until the first switching means goes into conduction at which time the current drawn through the voltage divider circuit will cause the voltage at the triac gate to be biased below cutoff, said first and second secondary windings being so constructed and adapted that the second secondary winding will supply a resonant capacitive load to the transformer when the triac is in conduction, and the first secondary winding will supply battery charging power to the battery so long as the secondary windings are in resonant conduction.

Claim 8

The device of claim 5 wherein the first switching means is a primary unijunction transistor, the first lead being the gate thereof, the second lead being the cathode thereof, and the third lead being the anode thereof.

Claim 9

The device of claim 5 wherein the second switching means is a transistor, the first lead being the collector thereof, the second lead being the emitter thereof, and the third lead being the base thereof.

Claim 10

The device of claim 5 wherein the second switching means is a means for turning off conduction of the first switching means and simultaneously turning on conduction of the triac every half cycle.

Claim 11

A float charging device comprising a ferro-resonant transformer including a primary winding for supplying power and a first and second secondary winding, charging means operatively connected to the first winding for supplying charging power to a battery from the transformer, control means operatively connected to the second secondary winding for providing a capacitive load to the transformer during conduction of current in the second secondary winding, an automatic switching means for cutting off flow of current in the second secondary winding when the battery terminal voltage attains a preselected magnitude, said switching means including a first electronic switch which goes into conduction when the battery attains the preselected terminal voltage, and a second electronic switch which resets the first electronic switch each half cycle whereby to provide continuous monitoring of the battery terminal voltage.

Claim 12

A float charging device comprising a ferro-resonant transformer including a primary winding for supplying power and a first and second secondary winding, charging means operatively connected to the first winding for supplying charging power to a battery from the transformer, control means operatively connected to the second secondary winding for providing a capacitive load to the transformer during conduction of current in the second secondary winding, an automatic switching means for cutting off flow of current in the second secondary winding when the battery terminal voltage attains a preselected magnitude, said switching means including a first electronic switch which goes into conduction when the battery attains the preselected terminal voltage, and a second electronic switch which resets the first electronic switch each half cycle whereby to provide continuous monitoring of the battery terminal voltage.